[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Explain what this code does and identify the inference stage it belongs to.

File: ds4_server.c

```c
har flags[64];
    log_flags(flags, sizeof(flags), p->responses_protocol,
              p->has_tools, false, false, false);
    const char *phase = p->phase ? p->phase : "prefill";
    server_log(DS4_LOG_PREFILL,
               "ds4-server: %s ctx=%s%s%s %s chunk %d/%d (%.1f%%) chunk=%.2f t/s avg=%.2f t/s %.3fs",
               p->kind == REQ_CHAT ? "chat" : "completion",
               p->ctx,
               flags[0] ? " " : "",
               flags,
               phase,
               display_current,
               display_total,
               pct,
               chunk_tps,
               avg_tps,
               elapsed);
    if (p->srv && current > p->cached_tokens) {
        kv_cache_maybe_store_continued(p->srv);
    }
}

static char *build_tool_checkpoint_suffix(const request *r, const char *content,
                                          const char *reasoning, const tool_calls *calls) {
    buf suffix = {0};
    if (ds4_think_mode_enabled(r->think_mode)) {
        buf_puts(&suffix, reasoning ? reasoning : "");
        buf_puts(&suffix, "</think>");
    }
    buf_puts(&suffix, content ? content : "");
    append_dsml_tool_calls_text(&suffix, calls);
    buf_puts(&suffix, "<｜end▁of▁sentence｜>");
    return buf_take(&suffix);
}

static char *build_responses_visible_assistant_suffix(const request *r,
                                                      const char *content,
                                                      const char *reasoning,
                                                      const tool_calls *calls) {
    buf suffix = {0};
    /* This suffix mirrors what a Responses client can replay, not necessarily
     * every token in KV.  Hidden reasoning stays live in the session unless the
     * next client replay is expected to include it.  In practice, pi replays
     * reasoning summaries for tool-call turns, but not for final assistant
     * answers; Codex currently requests no summaries at all.  So only include
     * reasoning in the remembered visible prefix when this assistant turn ended
     * in tool calls.  A client that does replay final-answer reasoning will not
     * match this visible shortcut and can still use exact token-prefix replay. */
    if (ds4_think_mode_enabled(r->think_mode)) {
        if (r->reasoning_summary_emit && calls && calls->len > 0) {
            buf_puts(&suffix, reasoning ? reasoning : "");
        }
        buf_puts(&suffix, "</think>");
    }
    buf_puts(&suffix, content ? content : "");
    append_dsml_tool_calls_text(&suffix, calls);
    buf_puts(&suffix, "<｜end▁of▁sentence｜>");
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Explain what this code does and identify the inference stage it belongs to.

File: ds4_server.c

```c
har flags[64];
    log_flags(flags, sizeof(flags), p->responses_protocol,
              p->has_tools, false, false, false);
    const char *phase = p->phase ? p->phase : "prefill";
    server_log(DS4_LOG_PREFILL,
               "ds4-server: %s ctx=%s%s%s %s chunk %d/%d (%.1f%%) chunk=%.2f t/s avg=%.2f t/s %.3fs",
               p->kind == REQ_CHAT ? "chat" : "completion",
               p->ctx,
               flags[0] ? " " : "",
               flags,
               phase,
               display_current,
               display_total,
               pct,
               chunk_tps,
               avg_tps,
               elapsed);
    if (p->srv && current > p->cached_tokens) {
        kv_cache_maybe_store_continued(p->srv);
    }
}

static char *build_tool_checkpoint_suffix(const request *r, const char *content,
                                          const char *reasoning, const tool_calls *calls) {
    buf suffix = {0};
    if (ds4_think_mode_enabled(r->think_mode)) {
        buf_puts(&suffix, reasoning ? reasoning : "");
        buf_puts(&suffix, "</think>");
    }
    buf_puts(&suffix, content ? content : "");
    append_dsml_tool_calls_text(&suffix, calls);
    buf_puts(&suffix, "<｜end▁of▁sentence｜>");
    return buf_take(&suffix);
}

static char *build_responses_visible_assistant_suffix(const request *r,
                                                      const char *content,
                                                      const char *reasoning,
                                                      const tool_calls *calls) {
    buf suffix = {0};
    /* This suffix mirrors what a Responses client can replay, not necessarily
     * every token in KV.  Hidden reasoning stays live in the session unless the
     * next client replay is expected to include it.  In practice, pi replays
     * reasoning summaries for tool-call turns, but not for final assistant
     * answers; Codex currently requests no summaries at all.  So only include
     * reasoning in the remembered visible prefix when this assistant turn ended
     * in tool calls.  A client that does replay final-answer reasoning will not
     * match this visible shortcut and can still use exact token-prefix replay. */
    if (ds4_think_mode_enabled(r->think_mode)) {
        if (r->reasoning_summary_emit && calls && calls->len > 0) {
            buf_puts(&suffix, reasoning ? reasoning : "");
        }
        buf_puts(&suffix, "</think>");
    }
    buf_puts(&suffix, content ? content : "");
    append_dsml_tool_calls_text(&suffix, calls);
    buf_puts(&suffix, "<｜end▁of▁sentence｜>");
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Explain what this code does and identify the inference stage it belongs to.

File: ds4_server.c

```c
har flags[64];
    log_flags(flags, sizeof(flags), p->responses_protocol,
              p->has_tools, false, false, false);
    const char *phase = p->phase ? p->phase : "prefill";
    server_log(DS4_LOG_PREFILL,
               "ds4-server: %s ctx=%s%s%s %s chunk %d/%d (%.1f%%) chunk=%.2f t/s avg=%.2f t/s %.3fs",
               p->kind == REQ_CHAT ? "chat" : "completion",
               p->ctx,
               flags[0] ? " " : "",
               flags,
               phase,
               display_current,
               display_total,
               pct,
               chunk_tps,
               avg_tps,
               elapsed);
    if (p->srv && current > p->cached_tokens) {
        kv_cache_maybe_store_continued(p->srv);
    }
}

static char *build_tool_checkpoint_suffix(const request *r, const char *content,
                                          const char *reasoning, const tool_calls *calls) {
    buf suffix = {0};
    if (ds4_think_mode_enabled(r->think_mode)) {
        buf_puts(&suffix, reasoning ? reasoning : "");
        buf_puts(&suffix, "</think>");
    }
    buf_puts(&suffix, content ? content : "");
    append_dsml_tool_calls_text(&suffix, calls);
    buf_puts(&suffix, "<｜end▁of▁sentence｜>");
    return buf_take(&suffix);
}

static char *build_responses_visible_assistant_suffix(const request *r,
                                                      const char *content,
                                                      const char *reasoning,
                                                      const tool_calls *calls) {
    buf suffix = {0};
    /* This suffix mirrors what a Responses client can replay, not necessarily
     * every token in KV.  Hidden reasoning stays live in the session unless the
     * next client replay is expected to include it.  In practice, pi replays
     * reasoning summaries for tool-call turns, but not for final assistant
     * answers; Codex currently requests no summaries at all.  So only include
     * reasoning in the remembered visible prefix when this assistant turn ended
     * in tool calls.  A client that does replay final-answer reasoning will not
     * match this visible shortcut and can still use exact token-prefix replay. */
    if (ds4_think_mode_enabled(r->think_mode)) {
        if (r->reasoning_summary_emit && calls && calls->len > 0) {
            buf_puts(&suffix, reasoning ? reasoning : "");
        }
        buf_puts(&suffix, "</think>");
    }
    buf_puts(&suffix, content ? content : "");
    append_dsml_tool_calls_text(&suffix, calls);
    buf_puts(&suffix, "<｜end▁of▁sentence｜>");
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Explain what this code does and identify the inference stage it belongs to.

File: ds4_server.c

```c
har flags[64];
    log_flags(flags, sizeof(flags), p->responses_protocol,
              p->has_tools, false, false, false);
    const char *phase = p->phase ? p->phase : "prefill";
    server_log(DS4_LOG_PREFILL,
               "ds4-server: %s ctx=%s%s%s %s chunk %d/%d (%.1f%%) chunk=%.2f t/s avg=%.2f t/s %.3fs",
               p->kind == REQ_CHAT ? "chat" : "completion",
               p->ctx,
               flags[0] ? " " : "",
               flags,
               phase,
               display_current,
               display_total,
               pct,
               chunk_tps,
               avg_tps,
               elapsed);
    if (p->srv && current > p->cached_tokens) {
        kv_cache_maybe_store_continued(p->srv);
    }
}

static char *build_tool_checkpoint_suffix(const request *r, const char *content,
                                          const char *reasoning, const tool_calls *calls) {
    buf suffix = {0};
    if (ds4_think_mode_enabled(r->think_mode)) {
        buf_puts(&suffix, reasoning ? reasoning : "");
        buf_puts(&suffix, "</think>");
    }
    buf_puts(&suffix, content ? content : "");
    append_dsml_tool_calls_text(&suffix, calls);
    buf_puts(&suffix, "<｜end▁of▁sentence｜>");
    return buf_take(&suffix);
}

static char *build_responses_visible_assistant_suffix(const request *r,
                                                      const char *content,
                                                      const char *reasoning,
                                                      const tool_calls *calls) {
    buf suffix = {0};
    /* This suffix mirrors what a Responses client can replay, not necessarily
     * every token in KV.  Hidden reasoning stays live in the session unless the
     * next client replay is expected to include it.  In practice, pi replays
     * reasoning summaries for tool-call turns, but not for final assistant
     * answers; Codex currently requests no summaries at all.  So only include
     * reasoning in the remembered visible prefix when this assistant turn ended
     * in tool calls.  A client that does replay final-answer reasoning will not
     * match this visible shortcut and can still use exact token-prefix replay. */
    if (ds4_think_mode_enabled(r->think_mode)) {
        if (r->reasoning_summary_emit && calls && calls->len > 0) {
            buf_puts(&suffix, reasoning ? reasoning : "");
        }
        buf_puts(&suffix, "</think>");
    }
    buf_puts(&suffix, content ? content : "");
    append_dsml_tool_calls_text(&suffix, calls);
    buf_puts(&suffix, "<｜end▁of▁sentence｜>");
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Suggest a minimal correctness-preserving optimization for this excerpt.

File: ds4_server.c

```c
buf_puts(&suffix, "</think>");
    }
    buf_puts(&suffix, content ? content : "");
    append_dsml_tool_calls_text(&suffix, calls);
    buf_puts(&suffix, "<｜end▁of▁sentence｜>");
    return buf_take(&suffix);
}

/* In thinking mode without tools, old assistant reasoning is intentionally not
 * rendered back into later prompts.  The sampled live graph still contains the
 * reasoning bytes, so the next request would miss the session cache even though
 * the visible conversation prefix is logically the same.
 *
 *   prompt-without-final-<think> + </think> + visible-content + eos
 *
 * is exactly the visible prefix that render_chat_prompt_text() will produce on
 * the next turn.  Do not rebuild the KV cache to erase hidden reasoning here:
 * that caused long post-answer pauses and threw away useful sampled state.
 * Instead, remember the visible bytes as a key for the current sampled frontier.
 * The next request can then continue from live KV while tokenizing only the new
 * visible suffix. */
static char *build_toolless_thinking_visible_text(const request *r,
                                                  const char *content) {
    if (!r || !r->prompt_text) return NULL;
    if (!ds4_think_mode_enabled(r->think_mode)) return NULL;

    size_t pt_len = strlen(r->prompt_text);
    const char *think_tag = "<think>";
    size_t tag_len = strlen(think_tag);
    if (pt_len < tag_len ||
        memcmp(r->prompt_text + pt_len - tag_len, think_tag, tag_len) != 0) {
        return NULL;
    }

    buf visible = {0};
    buf_append(&visible, r->prompt_text, pt_len - tag_len);
    buf_puts(&visible, "</think>");
    buf_puts(&visible, content ? content : "");
    buf_puts(&visible, "<｜end▁of▁sentence｜>");
    return buf_take(&visible);
}

static void remember_thinking_checkpoint(server *s, const job *j, const char *ctx,
                                         uint64_t trace_id, const char *content) {
    char *visible = build_toolless_thinking_visible_text(&j->req, content);
    if (!visible) return;

    thinking_live_remember(s, visible);
    server_log(DS4_LOG_KVCACHE,
               "ds4-server: thinking live checkpoint remembered ctx=%s live=%d visible=%zu",
               ctx, ds4_session_pos(s->session), strlen(visible));
    trace_event(s, trace_id,
                "thinking live checkpoint remembered: live=%d visible=%zu",
                ds4_session_pos(s->session), strlen(visible));
    free(visible);
}

/* After a successful tool-call finish, make the live checkpoint match what the
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Suggest a minimal correctness-preserving optimization for this excerpt.

File: ds4_server.c

```c
buf_puts(&suffix, "</think>");
    }
    buf_puts(&suffix, content ? content : "");
    append_dsml_tool_calls_text(&suffix, calls);
    buf_puts(&suffix, "<｜end▁of▁sentence｜>");
    return buf_take(&suffix);
}

/* In thinking mode without tools, old assistant reasoning is intentionally not
 * rendered back into later prompts.  The sampled live graph still contains the
 * reasoning bytes, so the next request would miss the session cache even though
 * the visible conversation prefix is logically the same.
 *
 *   prompt-without-final-<think> + </think> + visible-content + eos
 *
 * is exactly the visible prefix that render_chat_prompt_text() will produce on
 * the next turn.  Do not rebuild the KV cache to erase hidden reasoning here:
 * that caused long post-answer pauses and threw away useful sampled state.
 * Instead, remember the visible bytes as a key for the current sampled frontier.
 * The next request can then continue from live KV while tokenizing only the new
 * visible suffix. */
static char *build_toolless_thinking_visible_text(const request *r,
                                                  const char *content) {
    if (!r || !r->prompt_text) return NULL;
    if (!ds4_think_mode_enabled(r->think_mode)) return NULL;

    size_t pt_len = strlen(r->prompt_text);
    const char *think_tag = "<think>";
    size_t tag_len = strlen(think_tag);
    if (pt_len < tag_len ||
        memcmp(r->prompt_text + pt_len - tag_len, think_tag, tag_len) != 0) {
        return NULL;
    }

    buf visible = {0};
    buf_append(&visible, r->prompt_text, pt_len - tag_len);
    buf_puts(&visible, "</think>");
    buf_puts(&visible, content ? content : "");
    buf_puts(&visible, "<｜end▁of▁sentence｜>");
    return buf_take(&visible);
}

static void remember_thinking_checkpoint(server *s, const job *j, const char *ctx,
                                         uint64_t trace_id, const char *content) {
    char *visible = build_toolless_thinking_visible_text(&j->req, content);
    if (!visible) return;

    thinking_live_remember(s, visible);
    server_log(DS4_LOG_KVCACHE,
               "ds4-server: thinking live checkpoint remembered ctx=%s live=%d visible=%zu",
               ctx, ds4_session_pos(s->session), strlen(visible));
    trace_event(s, trace_id,
                "thinking live checkpoint remembered: live=%d visible=%zu",
                ds4_session_pos(s->session), strlen(visible));
    free(visible);
}

/* After a successful tool-call finish, make the live checkpoint match what the
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Suggest a minimal correctness-preserving optimization for this excerpt.

File: ds4_server.c

```c
buf_puts(&suffix, "</think>");
    }
    buf_puts(&suffix, content ? content : "");
    append_dsml_tool_calls_text(&suffix, calls);
    buf_puts(&suffix, "<｜end▁of▁sentence｜>");
    return buf_take(&suffix);
}

/* In thinking mode without tools, old assistant reasoning is intentionally not
 * rendered back into later prompts.  The sampled live graph still contains the
 * reasoning bytes, so the next request would miss the session cache even though
 * the visible conversation prefix is logically the same.
 *
 *   prompt-without-final-<think> + </think> + visible-content + eos
 *
 * is exactly the visible prefix that render_chat_prompt_text() will produce on
 * the next turn.  Do not rebuild the KV cache to erase hidden reasoning here:
 * that caused long post-answer pauses and threw away useful sampled state.
 * Instead, remember the visible bytes as a key for the current sampled frontier.
 * The next request can then continue from live KV while tokenizing only the new
 * visible suffix. */
static char *build_toolless_thinking_visible_text(const request *r,
                                                  const char *content) {
    if (!r || !r->prompt_text) return NULL;
    if (!ds4_think_mode_enabled(r->think_mode)) return NULL;

    size_t pt_len = strlen(r->prompt_text);
    const char *think_tag = "<think>";
    size_t tag_len = strlen(think_tag);
    if (pt_len < tag_len ||
        memcmp(r->prompt_text + pt_len - tag_len, think_tag, tag_len) != 0) {
        return NULL;
    }

    buf visible = {0};
    buf_append(&visible, r->prompt_text, pt_len - tag_len);
    buf_puts(&visible, "</think>");
    buf_puts(&visible, content ? content : "");
    buf_puts(&visible, "<｜end▁of▁sentence｜>");
    return buf_take(&visible);
}

static void remember_thinking_checkpoint(server *s, const job *j, const char *ctx,
                                         uint64_t trace_id, const char *content) {
    char *visible = build_toolless_thinking_visible_text(&j->req, content);
    if (!visible) return;

    thinking_live_remember(s, visible);
    server_log(DS4_LOG_KVCACHE,
               "ds4-server: thinking live checkpoint remembered ctx=%s live=%d visible=%zu",
               ctx, ds4_session_pos(s->session), strlen(visible));
    trace_event(s, trace_id,
                "thinking live checkpoint remembered: live=%d visible=%zu",
                ds4_session_pos(s->session), strlen(visible));
    free(visible);
}

/* After a successful tool-call finish, make the live checkpoint match what the
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Suggest a minimal correctness-preserving optimization for this excerpt.

File: ds4_server.c

```c
buf_puts(&suffix, "</think>");
    }
    buf_puts(&suffix, content ? content : "");
    append_dsml_tool_calls_text(&suffix, calls);
    buf_puts(&suffix, "<｜end▁of▁sentence｜>");
    return buf_take(&suffix);
}

/* In thinking mode without tools, old assistant reasoning is intentionally not
 * rendered back into later prompts.  The sampled live graph still contains the
 * reasoning bytes, so the next request would miss the session cache even though
 * the visible conversation prefix is logically the same.
 *
 *   prompt-without-final-<think> + </think> + visible-content + eos
 *
 * is exactly the visible prefix that render_chat_prompt_text() will produce on
 * the next turn.  Do not rebuild the KV cache to erase hidden reasoning here:
 * that caused long post-answer pauses and threw away useful sampled state.
 * Instead, remember the visible bytes as a key for the current sampled frontier.
 * The next request can then continue from live KV while tokenizing only the new
 * visible suffix. */
static char *build_toolless_thinking_visible_text(const request *r,
                                                  const char *content) {
    if (!r || !r->prompt_text) return NULL;
    if (!ds4_think_mode_enabled(r->think_mode)) return NULL;

    size_t pt_len = strlen(r->prompt_text);
    const char *think_tag = "<think>";
    size_t tag_len = strlen(think_tag);
    if (pt_len < tag_len ||
        memcmp(r->prompt_text + pt_len - tag_len, think_tag, tag_len) != 0) {
        return NULL;
    }

    buf visible = {0};
    buf_append(&visible, r->prompt_text, pt_len - tag_len);
    buf_puts(&visible, "</think>");
    buf_puts(&visible, content ? content : "");
    buf_puts(&visible, "<｜end▁of▁sentence｜>");
    return buf_take(&visible);
}

static void remember_thinking_checkpoint(server *s, const job *j, const char *ctx,
                                         uint64_t trace_id, const char *content) {
    char *visible = build_toolless_thinking_visible_text(&j->req, content);
    if (!visible) return;

    thinking_live_remember(s, visible);
    server_log(DS4_LOG_KVCACHE,
               "ds4-server: thinking live checkpoint remembered ctx=%s live=%d visible=%zu",
               ctx, ds4_session_pos(s->session), strlen(visible));
    trace_event(s, trace_id,
                "thinking live checkpoint remembered: live=%d visible=%zu",
                ds4_session_pos(s->session), strlen(visible));
    free(visible);
}

/* After a successful tool-call finish, make the live checkpoint match what the
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4_server.c

```c
d visible=%zu",
                ds4_session_pos(s->session), strlen(visible));
    free(visible);
}

/* After a successful tool-call finish, make the live checkpoint match what the
 * next request will render.  Usually that is just the exact DSML remembered by
 * tool id.  If a client sends a tool call without an id we know, the fallback
 * renderer still builds valid DSML from JSON, and this function either rewrites
 * the short suffix in place or reloads an older disk checkpoint before replay. */
static void canonicalize_tool_checkpoint(server *s, const job *j, const char *ctx,
                                         uint64_t trace_id, const char *content,
                                         const char *reasoning, const tool_calls *calls) {
    if (!calls || calls->len == 0 || !j->req.prompt_text) return;

    char *suffix_text = build_tool_checkpoint_suffix(&j->req, content, reasoning, calls);

    buf rendered = {0};
    buf_puts(&rendered, j->req.prompt_text);
    buf_puts(&rendered, suffix_text);

    ds4_tokens canonical = {0};
    ds4_tokenize_rendered_chat(s->engine, rendered.ptr ? rendered.ptr : "", &canonical);
    const int live_len = ds4_session_pos(s->session);
    const int common = ds4_session_common_prefix(s->session, &canonical);
    if (common == live_len && canonical.len == live_len) goto done;

    size_t live_text_len = 0;
    char *live_text = render_tokens_text(s->engine, ds4_session_tokens(s->session), &live_text_len);
    if (live_text_len == rendered.len &&
        (live_text_len == 0 || memcmp(live_text, rendered.ptr, live_text_len) == 0))
    {
        /* The graph already represents the bytes the next request will render.
         * Token-level canonicalization would only replace a valid sampled
         * history with a different BPE spelling of the same transcript. */
        free(live_text);
        goto done;
    }
    free(live_text);

    if (common < j->req.prompt.len) {
        trace_event(s, trace_id,
                    "tool checkpoint canonicalization skipped: common=%d prompt=%d live=%d canonical=%d",
                    common, j->req.prompt.len, live_len, canonical.len);
        goto done;
    }

    char err[160] = {0};
    ds4_session_rewrite_result rr =
        ds4_session_rewrite_from_common(s->session, &canonical, common,
                                        err, sizeof(err));
    if (rr == DS4_SESSION_REWRITE_OK) {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalized ctx=%s common=%d live=%d canonical=%d",
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4_server.c

```c
d visible=%zu",
                ds4_session_pos(s->session), strlen(visible));
    free(visible);
}

/* After a successful tool-call finish, make the live checkpoint match what the
 * next request will render.  Usually that is just the exact DSML remembered by
 * tool id.  If a client sends a tool call without an id we know, the fallback
 * renderer still builds valid DSML from JSON, and this function either rewrites
 * the short suffix in place or reloads an older disk checkpoint before replay. */
static void canonicalize_tool_checkpoint(server *s, const job *j, const char *ctx,
                                         uint64_t trace_id, const char *content,
                                         const char *reasoning, const tool_calls *calls) {
    if (!calls || calls->len == 0 || !j->req.prompt_text) return;

    char *suffix_text = build_tool_checkpoint_suffix(&j->req, content, reasoning, calls);

    buf rendered = {0};
    buf_puts(&rendered, j->req.prompt_text);
    buf_puts(&rendered, suffix_text);

    ds4_tokens canonical = {0};
    ds4_tokenize_rendered_chat(s->engine, rendered.ptr ? rendered.ptr : "", &canonical);
    const int live_len = ds4_session_pos(s->session);
    const int common = ds4_session_common_prefix(s->session, &canonical);
    if (common == live_len && canonical.len == live_len) goto done;

    size_t live_text_len = 0;
    char *live_text = render_tokens_text(s->engine, ds4_session_tokens(s->session), &live_text_len);
    if (live_text_len == rendered.len &&
        (live_text_len == 0 || memcmp(live_text, rendered.ptr, live_text_len) == 0))
    {
        /* The graph already represents the bytes the next request will render.
         * Token-level canonicalization would only replace a valid sampled
         * history with a different BPE spelling of the same transcript. */
        free(live_text);
        goto done;
    }
    free(live_text);

    if (common < j->req.prompt.len) {
        trace_event(s, trace_id,
                    "tool checkpoint canonicalization skipped: common=%d prompt=%d live=%d canonical=%d",
                    common, j->req.prompt.len, live_len, canonical.len);
        goto done;
    }

    char err[160] = {0};
    ds4_session_rewrite_result rr =
        ds4_session_rewrite_from_common(s->session, &canonical, common,
                                        err, sizeof(err));
    if (rr == DS4_SESSION_REWRITE_OK) {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalized ctx=%s common=%d live=%d canonical=%d",
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4_server.c

```c
d visible=%zu",
                ds4_session_pos(s->session), strlen(visible));
    free(visible);
}

/* After a successful tool-call finish, make the live checkpoint match what the
 * next request will render.  Usually that is just the exact DSML remembered by
 * tool id.  If a client sends a tool call without an id we know, the fallback
 * renderer still builds valid DSML from JSON, and this function either rewrites
 * the short suffix in place or reloads an older disk checkpoint before replay. */
static void canonicalize_tool_checkpoint(server *s, const job *j, const char *ctx,
                                         uint64_t trace_id, const char *content,
                                         const char *reasoning, const tool_calls *calls) {
    if (!calls || calls->len == 0 || !j->req.prompt_text) return;

    char *suffix_text = build_tool_checkpoint_suffix(&j->req, content, reasoning, calls);

    buf rendered = {0};
    buf_puts(&rendered, j->req.prompt_text);
    buf_puts(&rendered, suffix_text);

    ds4_tokens canonical = {0};
    ds4_tokenize_rendered_chat(s->engine, rendered.ptr ? rendered.ptr : "", &canonical);
    const int live_len = ds4_session_pos(s->session);
    const int common = ds4_session_common_prefix(s->session, &canonical);
    if (common == live_len && canonical.len == live_len) goto done;

    size_t live_text_len = 0;
    char *live_text = render_tokens_text(s->engine, ds4_session_tokens(s->session), &live_text_len);
    if (live_text_len == rendered.len &&
        (live_text_len == 0 || memcmp(live_text, rendered.ptr, live_text_len) == 0))
    {
        /* The graph already represents the bytes the next request will render.
         * Token-level canonicalization would only replace a valid sampled
         * history with a different BPE spelling of the same transcript. */
        free(live_text);
        goto done;
    }
    free(live_text);

    if (common < j->req.prompt.len) {
        trace_event(s, trace_id,
                    "tool checkpoint canonicalization skipped: common=%d prompt=%d live=%d canonical=%d",
                    common, j->req.prompt.len, live_len, canonical.len);
        goto done;
    }

    char err[160] = {0};
    ds4_session_rewrite_result rr =
        ds4_session_rewrite_from_common(s->session, &canonical, common,
                                        err, sizeof(err));
    if (rr == DS4_SESSION_REWRITE_OK) {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalized ctx=%s common=%d live=%d canonical=%d",
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4_server.c

```c
d visible=%zu",
                ds4_session_pos(s->session), strlen(visible));
    free(visible);
}

/* After a successful tool-call finish, make the live checkpoint match what the
 * next request will render.  Usually that is just the exact DSML remembered by
 * tool id.  If a client sends a tool call without an id we know, the fallback
 * renderer still builds valid DSML from JSON, and this function either rewrites
 * the short suffix in place or reloads an older disk checkpoint before replay. */
static void canonicalize_tool_checkpoint(server *s, const job *j, const char *ctx,
                                         uint64_t trace_id, const char *content,
                                         const char *reasoning, const tool_calls *calls) {
    if (!calls || calls->len == 0 || !j->req.prompt_text) return;

    char *suffix_text = build_tool_checkpoint_suffix(&j->req, content, reasoning, calls);

    buf rendered = {0};
    buf_puts(&rendered, j->req.prompt_text);
    buf_puts(&rendered, suffix_text);

    ds4_tokens canonical = {0};
    ds4_tokenize_rendered_chat(s->engine, rendered.ptr ? rendered.ptr : "", &canonical);
    const int live_len = ds4_session_pos(s->session);
    const int common = ds4_session_common_prefix(s->session, &canonical);
    if (common == live_len && canonical.len == live_len) goto done;

    size_t live_text_len = 0;
    char *live_text = render_tokens_text(s->engine, ds4_session_tokens(s->session), &live_text_len);
    if (live_text_len == rendered.len &&
        (live_text_len == 0 || memcmp(live_text, rendered.ptr, live_text_len) == 0))
    {
        /* The graph already represents the bytes the next request will render.
         * Token-level canonicalization would only replace a valid sampled
         * history with a different BPE spelling of the same transcript. */
        free(live_text);
        goto done;
    }
    free(live_text);

    if (common < j->req.prompt.len) {
        trace_event(s, trace_id,
                    "tool checkpoint canonicalization skipped: common=%d prompt=%d live=%d canonical=%d",
                    common, j->req.prompt.len, live_len, canonical.len);
        goto done;
    }

    char err[160] = {0};
    ds4_session_rewrite_result rr =
        ds4_session_rewrite_from_common(s->session, &canonical, common,
                                        err, sizeof(err));
    if (rr == DS4_SESSION_REWRITE_OK) {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalized ctx=%s common=%d live=%d canonical=%d",
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4_server.c

```c
sh(order, prop);
                if (!json_skip_value(&p)) return false;
                json_ws(&p);
                if (*p == ',') p++;
                json_ws(&p);
            }
            if (*p != '}') return false;
            p++;
        } else {
            free(key);
            if (!json_skip_value(&p)) return false;
        }
        json_ws(&p);
        if (*p == ',') p++;
        json_ws(&p);
    }
    return *p == '}';
}

static void tool_schema_orders_add_json_wire(tool_schema_orders *orders,
                                             const char *json,
                                             const char *namespace,
                                             const char *wire_name,
                                             bool responses_tool_search) {
    if (!orders || !json) return;
    const char *p = json;
    json_ws(&p);
    if (*p != '{') return;
    p++;
    tool_schema_order order = {0};
    json_ws(&p);
    while (*p && *p != '}') {
        char *key = NULL;
        if (!json_string(&p, &key)) goto done;
        json_ws(&p);
        if (*p != ':') {
            free(key);
            goto done;
        }
        p++;
        if (!strcmp(key, "name")) {
            free(order.name);
            if (!json_string(&p, &order.name)) {
                free(key);
                goto done;
            }
        } else if (!strcmp(key, "input_schema") || !strcmp(key, "parameters")) {
            char *schema = NULL;
            if (!json_raw_value(&p, &schema)) {
                free(key);
                goto done;
            }
            parse_schema_properties(schema, &order);
            free(schema);
        } else if (!json_skip_value(&p)) {
            free(key);
            goto done;
        }
        free(key);
        json_ws(&p);
        if (*p == ',') p++;
        json_ws(&p);
    }
    if (order.name) {
        if (namespace && namespace[0]) order.namespace = xstrdup(namespace);
        if (wire_name && wire_name[0]) order.wire_name = xstrdup(wire_name);
        order.responses_tool_search = responses_tool_search;
        tool_schema_orders_push(orders, order);
        memset(&order, 0, sizeof(order));
    }
done:
    tool_schema_order_free(&order);
}

static void tool_schema_orders_add_json(tool_schema_orders *orders, const char *json) {
    tool_schema_orders_add_json_wire(orders, json, NULL, NULL, false);
}

static bool append_responses_namespace_tool_schemas(buf *schemas,
                                                    tool_schema_orders *orders,
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4_server.c

```c
sh(order, prop);
                if (!json_skip_value(&p)) return false;
                json_ws(&p);
                if (*p == ',') p++;
                json_ws(&p);
            }
            if (*p != '}') return false;
            p++;
        } else {
            free(key);
            if (!json_skip_value(&p)) return false;
        }
        json_ws(&p);
        if (*p == ',') p++;
        json_ws(&p);
    }
    return *p == '}';
}

static void tool_schema_orders_add_json_wire(tool_schema_orders *orders,
                                             const char *json,
                                             const char *namespace,
                                             const char *wire_name,
                                             bool responses_tool_search) {
    if (!orders || !json) return;
    const char *p = json;
    json_ws(&p);
    if (*p != '{') return;
    p++;
    tool_schema_order order = {0};
    json_ws(&p);
    while (*p && *p != '}') {
        char *key = NULL;
        if (!json_string(&p, &key)) goto done;
        json_ws(&p);
        if (*p != ':') {
            free(key);
            goto done;
        }
        p++;
        if (!strcmp(key, "name")) {
            free(order.name);
            if (!json_string(&p, &order.name)) {
                free(key);
                goto done;
            }
        } else if (!strcmp(key, "input_schema") || !strcmp(key, "parameters")) {
            char *schema = NULL;
            if (!json_raw_value(&p, &schema)) {
                free(key);
                goto done;
            }
            parse_schema_properties(schema, &order);
            free(schema);
        } else if (!json_skip_value(&p)) {
            free(key);
            goto done;
        }
        free(key);
        json_ws(&p);
        if (*p == ',') p++;
        json_ws(&p);
    }
    if (order.name) {
        if (namespace && namespace[0]) order.namespace = xstrdup(namespace);
        if (wire_name && wire_name[0]) order.wire_name = xstrdup(wire_name);
        order.responses_tool_search = responses_tool_search;
        tool_schema_orders_push(orders, order);
        memset(&order, 0, sizeof(order));
    }
done:
    tool_schema_order_free(&order);
}

static void tool_schema_orders_add_json(tool_schema_orders *orders, const char *json) {
    tool_schema_orders_add_json_wire(orders, json, NULL, NULL, false);
}

static bool append_responses_namespace_tool_schemas(buf *schemas,
                                                    tool_schema_orders *orders,
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4_server.c

```c
sh(order, prop);
                if (!json_skip_value(&p)) return false;
                json_ws(&p);
                if (*p == ',') p++;
                json_ws(&p);
            }
            if (*p != '}') return false;
            p++;
        } else {
            free(key);
            if (!json_skip_value(&p)) return false;
        }
        json_ws(&p);
        if (*p == ',') p++;
        json_ws(&p);
    }
    return *p == '}';
}

static void tool_schema_orders_add_json_wire(tool_schema_orders *orders,
                                             const char *json,
                                             const char *namespace,
                                             const char *wire_name,
                                             bool responses_tool_search) {
    if (!orders || !json) return;
    const char *p = json;
    json_ws(&p);
    if (*p != '{') return;
    p++;
    tool_schema_order order = {0};
    json_ws(&p);
    while (*p && *p != '}') {
        char *key = NULL;
        if (!json_string(&p, &key)) goto done;
        json_ws(&p);
        if (*p != ':') {
            free(key);
            goto done;
        }
        p++;
        if (!strcmp(key, "name")) {
            free(order.name);
            if (!json_string(&p, &order.name)) {
                free(key);
                goto done;
            }
        } else if (!strcmp(key, "input_schema") || !strcmp(key, "parameters")) {
            char *schema = NULL;
            if (!json_raw_value(&p, &schema)) {
                free(key);
                goto done;
            }
            parse_schema_properties(schema, &order);
            free(schema);
        } else if (!json_skip_value(&p)) {
            free(key);
            goto done;
        }
        free(key);
        json_ws(&p);
        if (*p == ',') p++;
        json_ws(&p);
    }
    if (order.name) {
        if (namespace && namespace[0]) order.namespace = xstrdup(namespace);
        if (wire_name && wire_name[0]) order.wire_name = xstrdup(wire_name);
        order.responses_tool_search = responses_tool_search;
        tool_schema_orders_push(orders, order);
        memset(&order, 0, sizeof(order));
    }
done:
    tool_schema_order_free(&order);
}

static void tool_schema_orders_add_json(tool_schema_orders *orders, const char *json) {
    tool_schema_orders_add_json_wire(orders, json, NULL, NULL, false);
}

static bool append_responses_namespace_tool_schemas(buf *schemas,
                                                    tool_schema_orders *orders,
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4_server.c

```c
sh(order, prop);
                if (!json_skip_value(&p)) return false;
                json_ws(&p);
                if (*p == ',') p++;
                json_ws(&p);
            }
            if (*p != '}') return false;
            p++;
        } else {
            free(key);
            if (!json_skip_value(&p)) return false;
        }
        json_ws(&p);
        if (*p == ',') p++;
        json_ws(&p);
    }
    return *p == '}';
}

static void tool_schema_orders_add_json_wire(tool_schema_orders *orders,
                                             const char *json,
                                             const char *namespace,
                                             const char *wire_name,
                                             bool responses_tool_search) {
    if (!orders || !json) return;
    const char *p = json;
    json_ws(&p);
    if (*p != '{') return;
    p++;
    tool_schema_order order = {0};
    json_ws(&p);
    while (*p && *p != '}') {
        char *key = NULL;
        if (!json_string(&p, &key)) goto done;
        json_ws(&p);
        if (*p != ':') {
            free(key);
            goto done;
        }
        p++;
        if (!strcmp(key, "name")) {
            free(order.name);
            if (!json_string(&p, &order.name)) {
                free(key);
                goto done;
            }
        } else if (!strcmp(key, "input_schema") || !strcmp(key, "parameters")) {
            char *schema = NULL;
            if (!json_raw_value(&p, &schema)) {
                free(key);
                goto done;
            }
            parse_schema_properties(schema, &order);
            free(schema);
        } else if (!json_skip_value(&p)) {
            free(key);
            goto done;
        }
        free(key);
        json_ws(&p);
        if (*p == ',') p++;
        json_ws(&p);
    }
    if (order.name) {
        if (namespace && namespace[0]) order.namespace = xstrdup(namespace);
        if (wire_name && wire_name[0]) order.wire_name = xstrdup(wire_name);
        order.responses_tool_search = responses_tool_search;
        tool_schema_orders_push(orders, order);
        memset(&order, 0, sizeof(order));
    }
done:
    tool_schema_order_free(&order);
}

static void tool_schema_orders_add_json(tool_schema_orders *orders, const char *json) {
    tool_schema_orders_add_json_wire(orders, json, NULL, NULL, false);
}

static bool append_responses_namespace_tool_schemas(buf *schemas,
                                                    tool_schema_orders *orders,
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4_server.c

```c
);
    if (rr == DS4_SESSION_REWRITE_OK) {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalized ctx=%s common=%d live=%d canonical=%d",
                   ctx, common, live_len, canonical.len);
        trace_event(s, trace_id,
                    "tool checkpoint canonicalized: common=%d live=%d canonical=%d",
                    common, live_len, canonical.len);
    } else if (rr == DS4_SESSION_REWRITE_REBUILD_NEEDED) {
        /* The generated DSML suffix and the canonical prompt share a prefix,
         * but the generated tail is too large to overwrite safely inside the
         * live raw-window ring.  Prefer an older disk checkpoint over replaying
         * a very long conversation from token zero. */
        char *path = NULL;
        ds4_tokens effective = {0};
        int loaded = kv_cache_try_load_text(s, rendered.ptr ? rendered.ptr : "",
                                            &effective, &path, NULL, false);
        if (loaded == 0) ds4_session_invalidate(s->session);

        char sync_err[160] = {0};
        const ds4_tokens *sync_prompt = loaded > 0 ? &effective : &canonical;
        char rebuild_ctx[48];
        request_ctx_span(rebuild_ctx, sizeof(rebuild_ctx), loaded, sync_prompt->len);
        int replay_tokens = sync_prompt->len - loaded;
        if (replay_tokens < 0) replay_tokens = sync_prompt->len;
        int canonical_tail_tokens = canonical.len - common;
        if (canonical_tail_tokens < 0) canonical_tail_tokens = canonical.len;
        int discarded_live_tokens = live_len - common;
        if (discarded_live_tokens < 0) discarded_live_tokens = 0;
        const char *source = loaded > 0 ? "disk" : "full";
        const double rebuild_t0 = now_sec();
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalization needs %d tokens rebuild ctx=%s request_ctx=%s reason=canonical-tail-rewrite tail=%d discard=%d common=%d live=%d target=%d cached=%d source=%s%s%s",
                   replay_tokens,
                   rebuild_ctx,
                   ctx,
                   canonical_tail_tokens,
                   discarded_live_tokens,
                   common,
                   live_len,
                   canonical.len,
                   loaded,
                   source,
                   path ? " file=" : "",
                   path ? path : "");
        server_prefill_progress rebuild_progress = {
            .srv = s,
            .kind = j->req.kind,
            .prompt_tokens = sync_prompt->len,
            .cached_tokens = loaded,
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4_server.c

```c
);
    if (rr == DS4_SESSION_REWRITE_OK) {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalized ctx=%s common=%d live=%d canonical=%d",
                   ctx, common, live_len, canonical.len);
        trace_event(s, trace_id,
                    "tool checkpoint canonicalized: common=%d live=%d canonical=%d",
                    common, live_len, canonical.len);
    } else if (rr == DS4_SESSION_REWRITE_REBUILD_NEEDED) {
        /* The generated DSML suffix and the canonical prompt share a prefix,
         * but the generated tail is too large to overwrite safely inside the
         * live raw-window ring.  Prefer an older disk checkpoint over replaying
         * a very long conversation from token zero. */
        char *path = NULL;
        ds4_tokens effective = {0};
        int loaded = kv_cache_try_load_text(s, rendered.ptr ? rendered.ptr : "",
                                            &effective, &path, NULL, false);
        if (loaded == 0) ds4_session_invalidate(s->session);

        char sync_err[160] = {0};
        const ds4_tokens *sync_prompt = loaded > 0 ? &effective : &canonical;
        char rebuild_ctx[48];
        request_ctx_span(rebuild_ctx, sizeof(rebuild_ctx), loaded, sync_prompt->len);
        int replay_tokens = sync_prompt->len - loaded;
        if (replay_tokens < 0) replay_tokens = sync_prompt->len;
        int canonical_tail_tokens = canonical.len - common;
        if (canonical_tail_tokens < 0) canonical_tail_tokens = canonical.len;
        int discarded_live_tokens = live_len - common;
        if (discarded_live_tokens < 0) discarded_live_tokens = 0;
        const char *source = loaded > 0 ? "disk" : "full";
        const double rebuild_t0 = now_sec();
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalization needs %d tokens rebuild ctx=%s request_ctx=%s reason=canonical-tail-rewrite tail=%d discard=%d common=%d live=%d target=%d cached=%d source=%s%s%s",
                   replay_tokens,
                   rebuild_ctx,
                   ctx,
                   canonical_tail_tokens,
                   discarded_live_tokens,
                   common,
                   live_len,
                   canonical.len,
                   loaded,
                   source,
                   path ? " file=" : "",
                   path ? path : "");
        server_prefill_progress rebuild_progress = {
            .srv = s,
            .kind = j->req.kind,
            .prompt_tokens = sync_prompt->len,
            .cached_tokens = loaded,
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4_server.c

```c
);
    if (rr == DS4_SESSION_REWRITE_OK) {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalized ctx=%s common=%d live=%d canonical=%d",
                   ctx, common, live_len, canonical.len);
        trace_event(s, trace_id,
                    "tool checkpoint canonicalized: common=%d live=%d canonical=%d",
                    common, live_len, canonical.len);
    } else if (rr == DS4_SESSION_REWRITE_REBUILD_NEEDED) {
        /* The generated DSML suffix and the canonical prompt share a prefix,
         * but the generated tail is too large to overwrite safely inside the
         * live raw-window ring.  Prefer an older disk checkpoint over replaying
         * a very long conversation from token zero. */
        char *path = NULL;
        ds4_tokens effective = {0};
        int loaded = kv_cache_try_load_text(s, rendered.ptr ? rendered.ptr : "",
                                            &effective, &path, NULL, false);
        if (loaded == 0) ds4_session_invalidate(s->session);

        char sync_err[160] = {0};
        const ds4_tokens *sync_prompt = loaded > 0 ? &effective : &canonical;
        char rebuild_ctx[48];
        request_ctx_span(rebuild_ctx, sizeof(rebuild_ctx), loaded, sync_prompt->len);
        int replay_tokens = sync_prompt->len - loaded;
        if (replay_tokens < 0) replay_tokens = sync_prompt->len;
        int canonical_tail_tokens = canonical.len - common;
        if (canonical_tail_tokens < 0) canonical_tail_tokens = canonical.len;
        int discarded_live_tokens = live_len - common;
        if (discarded_live_tokens < 0) discarded_live_tokens = 0;
        const char *source = loaded > 0 ? "disk" : "full";
        const double rebuild_t0 = now_sec();
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalization needs %d tokens rebuild ctx=%s request_ctx=%s reason=canonical-tail-rewrite tail=%d discard=%d common=%d live=%d target=%d cached=%d source=%s%s%s",
                   replay_tokens,
                   rebuild_ctx,
                   ctx,
                   canonical_tail_tokens,
                   discarded_live_tokens,
                   common,
                   live_len,
                   canonical.len,
                   loaded,
                   source,
                   path ? " file=" : "",
                   path ? path : "");
        server_prefill_progress rebuild_progress = {
            .srv = s,
            .kind = j->req.kind,
            .prompt_tokens = sync_prompt->len,
            .cached_tokens = loaded,
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4_server.c

```c
);
    if (rr == DS4_SESSION_REWRITE_OK) {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalized ctx=%s common=%d live=%d canonical=%d",
                   ctx, common, live_len, canonical.len);
        trace_event(s, trace_id,
                    "tool checkpoint canonicalized: common=%d live=%d canonical=%d",
                    common, live_len, canonical.len);
    } else if (rr == DS4_SESSION_REWRITE_REBUILD_NEEDED) {
        /* The generated DSML suffix and the canonical prompt share a prefix,
         * but the generated tail is too large to overwrite safely inside the
         * live raw-window ring.  Prefer an older disk checkpoint over replaying
         * a very long conversation from token zero. */
        char *path = NULL;
        ds4_tokens effective = {0};
        int loaded = kv_cache_try_load_text(s, rendered.ptr ? rendered.ptr : "",
                                            &effective, &path, NULL, false);
        if (loaded == 0) ds4_session_invalidate(s->session);

        char sync_err[160] = {0};
        const ds4_tokens *sync_prompt = loaded > 0 ? &effective : &canonical;
        char rebuild_ctx[48];
        request_ctx_span(rebuild_ctx, sizeof(rebuild_ctx), loaded, sync_prompt->len);
        int replay_tokens = sync_prompt->len - loaded;
        if (replay_tokens < 0) replay_tokens = sync_prompt->len;
        int canonical_tail_tokens = canonical.len - common;
        if (canonical_tail_tokens < 0) canonical_tail_tokens = canonical.len;
        int discarded_live_tokens = live_len - common;
        if (discarded_live_tokens < 0) discarded_live_tokens = 0;
        const char *source = loaded > 0 ? "disk" : "full";
        const double rebuild_t0 = now_sec();
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalization needs %d tokens rebuild ctx=%s request_ctx=%s reason=canonical-tail-rewrite tail=%d discard=%d common=%d live=%d target=%d cached=%d source=%s%s%s",
                   replay_tokens,
                   rebuild_ctx,
                   ctx,
                   canonical_tail_tokens,
                   discarded_live_tokens,
                   common,
                   live_len,
                   canonical.len,
                   loaded,
                   source,
                   path ? " file=" : "",
                   path ? path : "");
        server_prefill_progress rebuild_progress = {
            .srv = s,
            .kind = j->req.kind,
            .prompt_tokens = sync_prompt->len,
            .cached_tokens = loaded,
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Explain what this code does and identify the inference stage it belongs to.

File: ds4_server.c

```c
ver_prefill_progress rebuild_progress = {
            .srv = s,
            .kind = j->req.kind,
            .prompt_tokens = sync_prompt->len,
            .cached_tokens = loaded,
            .phase = "tool checkpoint rebuild",
            .has_tools = j->req.has_tools,
            .t0 = rebuild_t0,
        };
        snprintf(rebuild_progress.ctx, sizeof(rebuild_progress.ctx), "%s", rebuild_ctx);
        ds4_session_set_progress(s->session, server_progress_cb, &rebuild_progress);
        if (ds4_session_sync(s->session, sync_prompt, sync_err, sizeof(sync_err)) == 0) {
            ds4_session_set_progress(s->session, NULL, NULL);
            const double rebuild_sec = now_sec() - rebuild_t0;
            if (loaded > 0) {
                server_log(DS4_LOG_KVCACHE,
                           "ds4-server: tool checkpoint rebuild done ctx=%s request_ctx=%s source=disk cached=%d replay=%d target=%d %.3fs",
                           rebuild_ctx, ctx, loaded, replay_tokens, canonical.len, rebuild_sec);
                trace_event(s, trace_id,
                            "tool checkpoint canonicalized via disk: common=%d live=%d canonical=%d cached=%d file=%s",
                            common, live_len, canonical.len, loaded, path ? path : "");
            } else {
                server_log(DS4_LOG_KVCACHE,
                           "ds4-server: tool checkpoint rebuild done ctx=%s request_ctx=%s source=full cached=0 replay=%d target=%d %.3fs",
                           rebuild_ctx, ctx, replay_tokens, canonical.len, rebuild_sec);
                trace_event(s, trace_id,
                            "tool checkpoint canonicalized via rebuild: common=%d live=%d canonical=%d reason=%s",
                            common, live_len, canonical.len, err);
            }
        } else {
            ds4_session_set_progress(s->session, NULL, NULL);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: tool checkpoint rebuild failed ctx=%s request_ctx=%s source=%s cached=%d replay=%d target=%d error=\"%s\"",
                       rebuild_ctx, ctx, source, loaded, replay_tokens,
                       canonical.len, sync_err);
            trace_event(s, trace_id, "tool checkpoint canonicalization failed after rebuild request: %s", sync_err);
        }
        ds4_tokens_free(&effective);
        free(path);
    } else {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalization failed ctx=%s common=%d live=%d canonical=%d error=\"%s\"",
                   ctx, common, live_len, canonical.len, err);
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Explain what this code does and identify the inference stage it belongs to.

File: ds4_server.c

```c
ver_prefill_progress rebuild_progress = {
            .srv = s,
            .kind = j->req.kind,
            .prompt_tokens = sync_prompt->len,
            .cached_tokens = loaded,
            .phase = "tool checkpoint rebuild",
            .has_tools = j->req.has_tools,
            .t0 = rebuild_t0,
        };
        snprintf(rebuild_progress.ctx, sizeof(rebuild_progress.ctx), "%s", rebuild_ctx);
        ds4_session_set_progress(s->session, server_progress_cb, &rebuild_progress);
        if (ds4_session_sync(s->session, sync_prompt, sync_err, sizeof(sync_err)) == 0) {
            ds4_session_set_progress(s->session, NULL, NULL);
            const double rebuild_sec = now_sec() - rebuild_t0;
            if (loaded > 0) {
                server_log(DS4_LOG_KVCACHE,
                           "ds4-server: tool checkpoint rebuild done ctx=%s request_ctx=%s source=disk cached=%d replay=%d target=%d %.3fs",
                           rebuild_ctx, ctx, loaded, replay_tokens, canonical.len, rebuild_sec);
                trace_event(s, trace_id,
                            "tool checkpoint canonicalized via disk: common=%d live=%d canonical=%d cached=%d file=%s",
                            common, live_len, canonical.len, loaded, path ? path : "");
            } else {
                server_log(DS4_LOG_KVCACHE,
                           "ds4-server: tool checkpoint rebuild done ctx=%s request_ctx=%s source=full cached=0 replay=%d target=%d %.3fs",
                           rebuild_ctx, ctx, replay_tokens, canonical.len, rebuild_sec);
                trace_event(s, trace_id,
                            "tool checkpoint canonicalized via rebuild: common=%d live=%d canonical=%d reason=%s",
                            common, live_len, canonical.len, err);
            }
        } else {
            ds4_session_set_progress(s->session, NULL, NULL);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: tool checkpoint rebuild failed ctx=%s request_ctx=%s source=%s cached=%d replay=%d target=%d error=\"%s\"",
                       rebuild_ctx, ctx, source, loaded, replay_tokens,
                       canonical.len, sync_err);
            trace_event(s, trace_id, "tool checkpoint canonicalization failed after rebuild request: %s", sync_err);
        }
        ds4_tokens_free(&effective);
        free(path);
    } else {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalization failed ctx=%s common=%d live=%d canonical=%d error=\"%s\"",
                   ctx, common, live_len, canonical.len, err);
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Explain what this code does and identify the inference stage it belongs to.

File: ds4_server.c

```c
ver_prefill_progress rebuild_progress = {
            .srv = s,
            .kind = j->req.kind,
            .prompt_tokens = sync_prompt->len,
            .cached_tokens = loaded,
            .phase = "tool checkpoint rebuild",
            .has_tools = j->req.has_tools,
            .t0 = rebuild_t0,
        };
        snprintf(rebuild_progress.ctx, sizeof(rebuild_progress.ctx), "%s", rebuild_ctx);
        ds4_session_set_progress(s->session, server_progress_cb, &rebuild_progress);
        if (ds4_session_sync(s->session, sync_prompt, sync_err, sizeof(sync_err)) == 0) {
            ds4_session_set_progress(s->session, NULL, NULL);
            const double rebuild_sec = now_sec() - rebuild_t0;
            if (loaded > 0) {
                server_log(DS4_LOG_KVCACHE,
                           "ds4-server: tool checkpoint rebuild done ctx=%s request_ctx=%s source=disk cached=%d replay=%d target=%d %.3fs",
                           rebuild_ctx, ctx, loaded, replay_tokens, canonical.len, rebuild_sec);
                trace_event(s, trace_id,
                            "tool checkpoint canonicalized via disk: common=%d live=%d canonical=%d cached=%d file=%s",
                            common, live_len, canonical.len, loaded, path ? path : "");
            } else {
                server_log(DS4_LOG_KVCACHE,
                           "ds4-server: tool checkpoint rebuild done ctx=%s request_ctx=%s source=full cached=0 replay=%d target=%d %.3fs",
                           rebuild_ctx, ctx, replay_tokens, canonical.len, rebuild_sec);
                trace_event(s, trace_id,
                            "tool checkpoint canonicalized via rebuild: common=%d live=%d canonical=%d reason=%s",
                            common, live_len, canonical.len, err);
            }
        } else {
            ds4_session_set_progress(s->session, NULL, NULL);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: tool checkpoint rebuild failed ctx=%s request_ctx=%s source=%s cached=%d replay=%d target=%d error=\"%s\"",
                       rebuild_ctx, ctx, source, loaded, replay_tokens,
                       canonical.len, sync_err);
            trace_event(s, trace_id, "tool checkpoint canonicalization failed after rebuild request: %s", sync_err);
        }
        ds4_tokens_free(&effective);
        free(path);
    } else {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalization failed ctx=%s common=%d live=%d canonical=%d error=\"%s\"",
                   ctx, common, live_len, canonical.len, err);
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Explain what this code does and identify the inference stage it belongs to.

File: ds4_server.c

```c
ver_prefill_progress rebuild_progress = {
            .srv = s,
            .kind = j->req.kind,
            .prompt_tokens = sync_prompt->len,
            .cached_tokens = loaded,
            .phase = "tool checkpoint rebuild",
            .has_tools = j->req.has_tools,
            .t0 = rebuild_t0,
        };
        snprintf(rebuild_progress.ctx, sizeof(rebuild_progress.ctx), "%s", rebuild_ctx);
        ds4_session_set_progress(s->session, server_progress_cb, &rebuild_progress);
        if (ds4_session_sync(s->session, sync_prompt, sync_err, sizeof(sync_err)) == 0) {
            ds4_session_set_progress(s->session, NULL, NULL);
            const double rebuild_sec = now_sec() - rebuild_t0;
            if (loaded > 0) {
                server_log(DS4_LOG_KVCACHE,
                           "ds4-server: tool checkpoint rebuild done ctx=%s request_ctx=%s source=disk cached=%d replay=%d target=%d %.3fs",
                           rebuild_ctx, ctx, loaded, replay_tokens, canonical.len, rebuild_sec);
                trace_event(s, trace_id,
                            "tool checkpoint canonicalized via disk: common=%d live=%d canonical=%d cached=%d file=%s",
                            common, live_len, canonical.len, loaded, path ? path : "");
            } else {
                server_log(DS4_LOG_KVCACHE,
                           "ds4-server: tool checkpoint rebuild done ctx=%s request_ctx=%s source=full cached=0 replay=%d target=%d %.3fs",
                           rebuild_ctx, ctx, replay_tokens, canonical.len, rebuild_sec);
                trace_event(s, trace_id,
                            "tool checkpoint canonicalized via rebuild: common=%d live=%d canonical=%d reason=%s",
                            common, live_len, canonical.len, err);
            }
        } else {
            ds4_session_set_progress(s->session, NULL, NULL);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: tool checkpoint rebuild failed ctx=%s request_ctx=%s source=%s cached=%d replay=%d target=%d error=\"%s\"",
                       rebuild_ctx, ctx, source, loaded, replay_tokens,
                       canonical.len, sync_err);
            trace_event(s, trace_id, "tool checkpoint canonicalization failed after rebuild request: %s", sync_err);
        }
        ds4_tokens_free(&effective);
        free(path);
    } else {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: tool checkpoint canonicalization failed ctx=%s common=%d live=%d canonical=%d error=\"%s\"",
                   ctx, common, live_len, canonical.len, err);
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Suggest a minimal correctness-preserving optimization for this excerpt.

File: ds4_server.c

```c
"ds4-server: tool checkpoint canonicalization failed ctx=%s common=%d live=%d canonical=%d error=\"%s\"",
                   ctx, common, live_len, canonical.len, err);
        trace_event(s, trace_id, "tool checkpoint canonicalization failed: %s", err);
    }

done:
    ds4_tokens_free(&canonical);
    buf_free(&rendered);
    free(suffix_text);
}

static bool should_canonicalize_tool_checkpoint(const server *s, const tool_calls *calls) {
    if (!calls || calls->len == 0) return false;
    if (s && !s->disable_exact_dsml_tool_replay &&
        calls->raw_dsml && calls->raw_dsml[0])
    {
        return false;
    }
    return true;
}

/* Execute one request on the worker-owned session.
 *
 * Clients resend full prompts as text.  The worker first tries the old exact
 * token-prefix hit, then a rendered-text prefix hit for the live checkpoint,
 * then disk text-prefix restart snapshots, then a cold prefill.  On text-prefix
 * hits we build a fresh effective prompt from the checkpoint's exact token
 * history plus a newly tokenized string suffix; the canonical full-prompt
 * tokens are not sliced because BPE may merge across the byte boundary.  Cold
 * prompt caching is handled before generation: if the stable checkpoint is
 * shorter than the full prompt, we prefill to that boundary, store it, and
 * immediately continue to the real prompt.  The live graph therefore always
 * moves forward. */
static void generate_job(server *s, job *j) {
    char err[160];
    err[0] = '\0';
    const int old_pos = ds4_session_pos(s->session);
    const int common = ds4_session_common_prefix(s->session, &j->req.prompt);
    trace_cache_diag cache_diag = {0};
    trace_cache_capture(&cache_diag, ds4_session_tokens(s->session),
                        &j->req.prompt, old_pos, common);
    ds4_tokens effective_prompt = {0};
    const ds4_tokens *prompt_for_sync = &j->req.prompt;
    const bool responses_protocol = j->req.api == API_RESPONSES;
    bool responses_live_continuation = false;
    bool anthropic_live_continuation = false;
    bool thinking_live_continuation = false;
    const char *responses_live_match = NULL;
    int responses_live_match_ids = 0;
    int anthropic_live_match_ids = 0;
    /* Responses gets the first chance to continue from live state.  This is
     * the whole point of the API shape: a request that is bound to prior live
     * output by visible transcript or tool call ids does not need to prove an
     * exact token-prefix match.  Exact token/text/disk matching remains the
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Suggest a minimal correctness-preserving optimization for this excerpt.

File: ds4_server.c

```c
"ds4-server: tool checkpoint canonicalization failed ctx=%s common=%d live=%d canonical=%d error=\"%s\"",
                   ctx, common, live_len, canonical.len, err);
        trace_event(s, trace_id, "tool checkpoint canonicalization failed: %s", err);
    }

done:
    ds4_tokens_free(&canonical);
    buf_free(&rendered);
    free(suffix_text);
}

static bool should_canonicalize_tool_checkpoint(const server *s, const tool_calls *calls) {
    if (!calls || calls->len == 0) return false;
    if (s && !s->disable_exact_dsml_tool_replay &&
        calls->raw_dsml && calls->raw_dsml[0])
    {
        return false;
    }
    return true;
}

/* Execute one request on the worker-owned session.
 *
 * Clients resend full prompts as text.  The worker first tries the old exact
 * token-prefix hit, then a rendered-text prefix hit for the live checkpoint,
 * then disk text-prefix restart snapshots, then a cold prefill.  On text-prefix
 * hits we build a fresh effective prompt from the checkpoint's exact token
 * history plus a newly tokenized string suffix; the canonical full-prompt
 * tokens are not sliced because BPE may merge across the byte boundary.  Cold
 * prompt caching is handled before generation: if the stable checkpoint is
 * shorter than the full prompt, we prefill to that boundary, store it, and
 * immediately continue to the real prompt.  The live graph therefore always
 * moves forward. */
static void generate_job(server *s, job *j) {
    char err[160];
    err[0] = '\0';
    const int old_pos = ds4_session_pos(s->session);
    const int common = ds4_session_common_prefix(s->session, &j->req.prompt);
    trace_cache_diag cache_diag = {0};
    trace_cache_capture(&cache_diag, ds4_session_tokens(s->session),
                        &j->req.prompt, old_pos, common);
    ds4_tokens effective_prompt = {0};
    const ds4_tokens *prompt_for_sync = &j->req.prompt;
    const bool responses_protocol = j->req.api == API_RESPONSES;
    bool responses_live_continuation = false;
    bool anthropic_live_continuation = false;
    bool thinking_live_continuation = false;
    const char *responses_live_match = NULL;
    int responses_live_match_ids = 0;
    int anthropic_live_match_ids = 0;
    /* Responses gets the first chance to continue from live state.  This is
     * the whole point of the API shape: a request that is bound to prior live
     * output by visible transcript or tool call ids does not need to prove an
     * exact token-prefix match.  Exact token/text/disk matching remains the
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Suggest a minimal correctness-preserving optimization for this excerpt.

File: ds4_server.c

```c
"ds4-server: tool checkpoint canonicalization failed ctx=%s common=%d live=%d canonical=%d error=\"%s\"",
                   ctx, common, live_len, canonical.len, err);
        trace_event(s, trace_id, "tool checkpoint canonicalization failed: %s", err);
    }

done:
    ds4_tokens_free(&canonical);
    buf_free(&rendered);
    free(suffix_text);
}

static bool should_canonicalize_tool_checkpoint(const server *s, const tool_calls *calls) {
    if (!calls || calls->len == 0) return false;
    if (s && !s->disable_exact_dsml_tool_replay &&
        calls->raw_dsml && calls->raw_dsml[0])
    {
        return false;
    }
    return true;
}

/* Execute one request on the worker-owned session.
 *
 * Clients resend full prompts as text.  The worker first tries the old exact
 * token-prefix hit, then a rendered-text prefix hit for the live checkpoint,
 * then disk text-prefix restart snapshots, then a cold prefill.  On text-prefix
 * hits we build a fresh effective prompt from the checkpoint's exact token
 * history plus a newly tokenized string suffix; the canonical full-prompt
 * tokens are not sliced because BPE may merge across the byte boundary.  Cold
 * prompt caching is handled before generation: if the stable checkpoint is
 * shorter than the full prompt, we prefill to that boundary, store it, and
 * immediately continue to the real prompt.  The live graph therefore always
 * moves forward. */
static void generate_job(server *s, job *j) {
    char err[160];
    err[0] = '\0';
    const int old_pos = ds4_session_pos(s->session);
    const int common = ds4_session_common_prefix(s->session, &j->req.prompt);
    trace_cache_diag cache_diag = {0};
    trace_cache_capture(&cache_diag, ds4_session_tokens(s->session),
                        &j->req.prompt, old_pos, common);
    ds4_tokens effective_prompt = {0};
    const ds4_tokens *prompt_for_sync = &j->req.prompt;
    const bool responses_protocol = j->req.api == API_RESPONSES;
    bool responses_live_continuation = false;
    bool anthropic_live_continuation = false;
    bool thinking_live_continuation = false;
    const char *responses_live_match = NULL;
    int responses_live_match_ids = 0;
    int anthropic_live_match_ids = 0;
    /* Responses gets the first chance to continue from live state.  This is
     * the whole point of the API shape: a request that is bound to prior live
     * output by visible transcript or tool call ids does not need to prove an
     * exact token-prefix match.  Exact token/text/disk matching remains the
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Suggest a minimal correctness-preserving optimization for this excerpt.

File: ds4_server.c

```c
"ds4-server: tool checkpoint canonicalization failed ctx=%s common=%d live=%d canonical=%d error=\"%s\"",
                   ctx, common, live_len, canonical.len, err);
        trace_event(s, trace_id, "tool checkpoint canonicalization failed: %s", err);
    }

done:
    ds4_tokens_free(&canonical);
    buf_free(&rendered);
    free(suffix_text);
}

static bool should_canonicalize_tool_checkpoint(const server *s, const tool_calls *calls) {
    if (!calls || calls->len == 0) return false;
    if (s && !s->disable_exact_dsml_tool_replay &&
        calls->raw_dsml && calls->raw_dsml[0])
    {
        return false;
    }
    return true;
}

/* Execute one request on the worker-owned session.
 *
 * Clients resend full prompts as text.  The worker first tries the old exact
 * token-prefix hit, then a rendered-text prefix hit for the live checkpoint,
 * then disk text-prefix restart snapshots, then a cold prefill.  On text-prefix
 * hits we build a fresh effective prompt from the checkpoint's exact token
 * history plus a newly tokenized string suffix; the canonical full-prompt
 * tokens are not sliced because BPE may merge across the byte boundary.  Cold
 * prompt caching is handled before generation: if the stable checkpoint is
 * shorter than the full prompt, we prefill to that boundary, store it, and
 * immediately continue to the real prompt.  The live graph therefore always
 * moves forward. */
static void generate_job(server *s, job *j) {
    char err[160];
    err[0] = '\0';
    const int old_pos = ds4_session_pos(s->session);
    const int common = ds4_session_common_prefix(s->session, &j->req.prompt);
    trace_cache_diag cache_diag = {0};
    trace_cache_capture(&cache_diag, ds4_session_tokens(s->session),
                        &j->req.prompt, old_pos, common);
    ds4_tokens effective_prompt = {0};
    const ds4_tokens *prompt_for_sync = &j->req.prompt;
    const bool responses_protocol = j->req.api == API_RESPONSES;
    bool responses_live_continuation = false;
    bool anthropic_live_continuation = false;
    bool thinking_live_continuation = false;
    const char *responses_live_match = NULL;
    int responses_live_match_ids = 0;
    int anthropic_live_match_ids = 0;
    /* Responses gets the first chance to continue from live state.  This is
     * the whole point of the API shape: a request that is bound to prior live
     * output by visible transcript or tool call ids does not need to prove an
     * exact token-prefix match.  Exact token/text/disk matching remains the
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4_server.c

```c
t is bound to prior live
     * output by visible transcript or tool call ids does not need to prove an
     * exact token-prefix match.  Exact token/text/disk matching remains the
     * fallback when the live state is absent or no longer describes the
     * request. */
    int cached = responses_live_visible_prefix_prompt(s, &j->req, old_pos,
                                                      &effective_prompt);
    const char *cache_source = cached > 0 ? "responses-visible" : "none";
    if (cached > 0) {
        responses_live_match = "visible-prefix";
        if (responses_live_matches_request(s, &j->req.responses_live_call_ids,
                                           old_pos))
        {
            responses_live_match_ids = j->req.responses_live_call_ids.len;
        }
    }
    if (cached == 0) {
        cached = responses_live_continuation_prompt(s, &j->req, old_pos,
                                                    &effective_prompt,
                                                    &responses_live_match_ids);
        cache_source = cached > 0 ? "responses-tool-output" : "none";
        if (cached > 0) responses_live_match = "tool-output-ids";
    }
    if (cached > 0) {
        responses_live_continuation = true;
        prompt_for_sync = &effective_prompt;
    } else {
        cached = anthropic_live_continuation_prompt(s, &j->req, old_pos,
                                                    &effective_prompt,
                                                    &anthropic_live_match_ids);
        if (cached > 0) {
            anthropic_live_continuation = true;
            cache_source = "anthropic-tool-output";
            prompt_for_sync = &effective_prompt;
        }
    }
    if (cached == 0 && responses_protocol &&
        j->req.responses_requires_live_tool_state)
    {
        /* The parser saw a valid live call_id, but by worker execution time the
         * live frontier no longer matches.  Since the request did not replay
         * the prior assistant call, there is no stateless prefix to match and
         * no disk key to search by. */
        ds4_tokens_free(&effective_prompt);
        http_error(j->fd, s->enable_cors, 409,
                   "Responses continuation state is not available; retry by replaying the full input history");
        return;
    } else if (cached == 0 && j->req.api == API_ANTHROPIC &&
               j->req.anthropic_requires_live_tool_state)
    {
        ds4_tokens_free(&effective_prompt);
        http_error(j->fd, s->enable_cors, 409,
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4_server.c

```c
t is bound to prior live
     * output by visible transcript or tool call ids does not need to prove an
     * exact token-prefix match.  Exact token/text/disk matching remains the
     * fallback when the live state is absent or no longer describes the
     * request. */
    int cached = responses_live_visible_prefix_prompt(s, &j->req, old_pos,
                                                      &effective_prompt);
    const char *cache_source = cached > 0 ? "responses-visible" : "none";
    if (cached > 0) {
        responses_live_match = "visible-prefix";
        if (responses_live_matches_request(s, &j->req.responses_live_call_ids,
                                           old_pos))
        {
            responses_live_match_ids = j->req.responses_live_call_ids.len;
        }
    }
    if (cached == 0) {
        cached = responses_live_continuation_prompt(s, &j->req, old_pos,
                                                    &effective_prompt,
                                                    &responses_live_match_ids);
        cache_source = cached > 0 ? "responses-tool-output" : "none";
        if (cached > 0) responses_live_match = "tool-output-ids";
    }
    if (cached > 0) {
        responses_live_continuation = true;
        prompt_for_sync = &effective_prompt;
    } else {
        cached = anthropic_live_continuation_prompt(s, &j->req, old_pos,
                                                    &effective_prompt,
                                                    &anthropic_live_match_ids);
        if (cached > 0) {
            anthropic_live_continuation = true;
            cache_source = "anthropic-tool-output";
            prompt_for_sync = &effective_prompt;
        }
    }
    if (cached == 0 && responses_protocol &&
        j->req.responses_requires_live_tool_state)
    {
        /* The parser saw a valid live call_id, but by worker execution time the
         * live frontier no longer matches.  Since the request did not replay
         * the prior assistant call, there is no stateless prefix to match and
         * no disk key to search by. */
        ds4_tokens_free(&effective_prompt);
        http_error(j->fd, s->enable_cors, 409,
                   "Responses continuation state is not available; retry by replaying the full input history");
        return;
    } else if (cached == 0 && j->req.api == API_ANTHROPIC &&
               j->req.anthropic_requires_live_tool_state)
    {
        ds4_tokens_free(&effective_prompt);
        http_error(j->fd, s->enable_cors, 409,
```<｜Assistant｜></think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4_server.c

```c
t is bound to prior live
     * output by visible transcript or tool call ids does not need to prove an
     * exact token-prefix match.  Exact token/text/disk matching remains the
     * fallback when the live state is absent or no longer describes the
     * request. */
    int cached = responses_live_visible_prefix_prompt(s, &j->req, old_pos,
                                                      &effective_prompt);
    const char *cache_source = cached > 0 ? "responses-visible" : "none";
    if (cached > 0) {
        responses_live_match = "visible-prefix";
        if (responses_live_matches_request(s, &j->req.responses_live_call_ids,
                                           old_pos))
        {
            responses_live_match_ids = j->req.responses_live_call_ids.len;
        }
    }
    if (cached == 0) {
        cached = responses_live_continuation_prompt(s, &j->req, old_pos,
                                                    &effective_prompt,
                                                    &responses_live_match_ids);
        cache_source = cached > 0 ? "responses-tool-output" : "none";
        if (cached > 0) responses_live_match = "tool-output-ids";
    }
    if (cached > 0) {
        responses_live_continuation = true;
        prompt_for_sync = &effective_prompt;
    } else {
        cached = anthropic_live_continuation_prompt(s, &j->req, old_pos,
                                                    &effective_prompt,
                                                    &anthropic_live_match_ids);
        if (cached > 0) {
            anthropic_live_continuation = true;
            cache_source = "anthropic-tool-output";
            prompt_for_sync = &effective_prompt;
        }
    }
    if (cached == 0 && responses_protocol &&
        j->req.responses_requires_live_tool_state)
    {
        /* The parser saw a valid live call_id, but by worker execution time the
         * live frontier no longer matches.  Since the request did not replay
         * the prior assistant call, there is no stateless prefix to match and
         * no disk key to search by. */
        ds4_tokens_free(&effective_prompt);
        http_error(j->fd, s->enable_cors, 409,
                   "Responses continuation state is not available; retry by replaying the full input history");
        return;
    } else if (cached == 0 && j->req.api == API_ANTHROPIC &&
               j->req.anthropic_requires_live_tool_state)
    {
        ds4_tokens_free(&effective_prompt);
        http_error(j->fd, s->enable_cors, 409,
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Trova bug sottili e spiega quali invarianti dell'inferenza possono rompersi.

File: ds4_server.c

```c
t is bound to prior live
     * output by visible transcript or tool call ids does not need to prove an
     * exact token-prefix match.  Exact token/text/disk matching remains the
     * fallback when the live state is absent or no longer describes the
     * request. */
    int cached = responses_live_visible_prefix_prompt(s, &j->req, old_pos,
                                                      &effective_prompt);
    const char *cache_source = cached > 0 ? "responses-visible" : "none";
    if (cached > 0) {
        responses_live_match = "visible-prefix";
        if (responses_live_matches_request(s, &j->req.responses_live_call_ids,
                                           old_pos))
        {
            responses_live_match_ids = j->req.responses_live_call_ids.len;
        }
    }
    if (cached == 0) {
        cached = responses_live_continuation_prompt(s, &j->req, old_pos,
                                                    &effective_prompt,
                                                    &responses_live_match_ids);
        cache_source = cached > 0 ? "responses-tool-output" : "none";
        if (cached > 0) responses_live_match = "tool-output-ids";
    }
    if (cached > 0) {
        responses_live_continuation = true;
        prompt_for_sync = &effective_prompt;
    } else {
        cached = anthropic_live_continuation_prompt(s, &j->req, old_pos,
                                                    &effective_prompt,
                                                    &anthropic_live_match_ids);
        if (cached > 0) {
            anthropic_live_continuation = true;
            cache_source = "anthropic-tool-output";
            prompt_for_sync = &effective_prompt;
        }
    }
    if (cached == 0 && responses_protocol &&
        j->req.responses_requires_live_tool_state)
    {
        /* The parser saw a valid live call_id, but by worker execution time the
         * live frontier no longer matches.  Since the request did not replay
         * the prior assistant call, there is no stateless prefix to match and
         * no disk key to search by. */
        ds4_tokens_free(&effective_prompt);
        http_error(j->fd, s->enable_cors, 409,
                   "Responses continuation state is not available; retry by replaying the full input history");
        return;
    } else if (cached == 0 && j->req.api == API_ANTHROPIC &&
               j->req.anthropic_requires_live_tool_state)
    {
        ds4_tokens_free(&effective_prompt);
        http_error(j->fd, s->enable_cors, 409,
```<｜Assistant｜><think>


[System] You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.

[User]
Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4_server.c

```c
q.api == API_ANTHROPIC &&
               j->req.anthropic_requires_live_tool_state)
    {
        ds4_tokens_free(&effective_prompt);
        http_error(j->fd, s->enable_cors, 409,
                   "Anthropic continuation state is not available; retry by replaying the full messages history");
        return;
    } else if (cached == 0) {
        cached = common == old_pos && j->req.prompt.len >= old_pos ? common : 0;
        cache_source = cached > 0 ? "memory-token" : "none";
    }
    if (cached == 0) {
        int thinking_cached =
            thinking_live_visible_prefix_prompt(s, &j->req, old_pos,
                                                &effective_prompt);
        if (thinking_cached > 0) {
            cached = thinking_cached;
            cache_source = "thinking-visible";
            thinking_live_continuation = true;
            prompt_for_sync = &effective_prompt;
        }
    }
    int disk_cached = 0;
    char *disk_cache_path = NULL;
    uint8_t disk_cache_ext_flags = 0;
    if (cached == 0) {
        int text_cached = live_text_prefix_prompt(s, &j->req, &effective_prompt);
        if (text_cached > 0) {
            cached = text_cached;
            cache_source = "memory-text";
            prompt_for_sync = &effective_prompt;
        }
    }
    if (cached == 0 && old_pos > 0) {
        server_log(DS4_LOG_WARNING,
                   "ds4-server: live kv cache miss%s live=%d prompt=%d common=%d reason=%s",
                   responses_protocol ? " RESPPROTO" : "",
                   old_pos, j->req.prompt.len, common,
                   trace_cache_miss_reason(&cache_diag));
    }
    if (cached == 0) s->kv.continued_last_store_tokens = 0;
    if (s->kv.enabled && cached == 0 && old_pos >= s->kv.opt.min_tokens) {
        /* Loading a disk snapshot replaces the live Metal session.  Persist the
         * current checkpoint first, otherwise a cache hit for an older prefix
         * would silently discard the newer conversation state. */
        kv_cache_store_current(s, "evict");
    }
    if (cached == 0) {
        disk_cached = kv_cache_try_load(s, &j->req, &effective_prompt,
                                        &disk_cache_path,
                                        &disk_cache_ext_flags);
        if (disk_cached > 0) {
            cached = disk_cached;
            cache_source = "disk-text";
            prompt_for_sync = &effective_prompt;
        }
    }
    const bool responses_reasoning_state_preserved =
        cached > 0 &&
        ((!strcmp(cache_source, "responses-visible") ||
```

<｜begin▁of▁sentence｜>You are DeepSeek V4 Flash running locally. Answer accurately, preserve technical details, and use tools only when the prompt asks for tool use.<｜User｜>Review this excerpt for correctness risks, memory lifetime issues, and performance bottlenecks.

File: ds4_server.c

```c
q.api == API_ANTHROPIC &&
               j->req.anthropic_requires_live_tool_state)
    {
        ds4_tokens_free(&effective_prompt);
        http_error(j->fd, s->enable_cors, 409,
                   "Anthropic continuation state is not available; retry by replaying the full messages history");
        return;
    } else if (cached == 0) {
        cached = common == old_pos && j->req.prompt.len >= old_pos ? common : 0;
        cache_source = cached > 0 ? "memory-token" : "none";
    }
    if (cached == 0) {
        int thinking_cached =
            thinking_live_visible_prefix_prompt(s, &j->req, old_pos,
                                                &effective_prompt);
        if (thinking_cached > 0) {
            cached = thinking_cached;
            cache_source = "thinking-visible";
            thinking_live_continuation = true;
            prompt_for_sync = &effective_prompt;
        }
    }
    int disk_cached = 0;
    char *disk_cache_path = NULL;
    uint8_t disk_cache_ext_flags = 0;
    if (cached == 0) {
        int text_cached = live_text_prefix_prompt(s, &j->req, &effective_prompt);
        if (text_cached > 0) {
            cached = text_cached;
            cache_source = "memory-text";
            prompt_for_sync = &effective_prompt;
        }
    }
    if (cached == 0 && old_pos > 0) {
        server_log(DS4_LOG_WARNING,
                   "ds4-server: live kv cache miss%s live=%d prompt=%d common=%d reason=%s",
                   responses_protocol ? " RESPPROTO" : "",
                   old_pos, j->req.prompt.len, common,
                   trace_cache_miss_reason(&cache_diag));
    }
    if (cached == 0) s->kv.continued_last_store_tokens = 0;
    if (s->kv.enabled && cached == 0 && old_pos >= s->kv.opt.min_tokens) {
        /* Loading a disk snapshot replaces the live Metal session.  Persist the
         * current checkpoint first, otherwise a cache hit for an older prefix
         * would silently discard the newer conversation state. */
        kv_cache_store_current(s, "evict");
    }
    if (cached == 0) {
        disk_cached = kv_cache_try_load(s, &j->req, &effective_prompt,
                                        &disk_cache_path,
                                        &disk_cache_ext_flags);
        if (disk_cached > 0) {
            cached = disk_cached;
            cache_source = "disk-text";
            prompt_for_sync = &effective_prompt;
        }
    }
    const bool responses_reasoning_state_preserved =
        cached > 0 &&
        ((!strcmp(cache_source, "responses-visible") ||
```<｜Assistant｜></think>