[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
(uint32_t)store_tokens.len, 0,
                   (uint32_t)ds4_session_ctx(s->session), now, now, payload_bytes);
    uint8_t tb[4];
    le_put32(tb, (uint32_t)text_len);
    uint64_t tool_map_bytes = 0;
    errno = 0;
    bool ok = fwrite(h, 1, sizeof(h), fp) == sizeof(h) &&
              fwrite(tb, 1, sizeof(tb), fp) == sizeof(tb) &&
              fwrite(text, 1, text_len, fp) == text_len &&
              ds4_session_save_payload(s->session, fp, err, sizeof(err)) == 0 &&
              kv_tool_map_write(s, fp, text, &tool_map_bytes) &&
              fflush(fp) == 0;
    int saved_errno = errno;
    if (fclose(fp) != 0) {
        if (!saved_errno) saved_errno = errno;
        ok = false;
    }
    uint64_t final_file_bytes = 0, final_required_bytes = 0;
    bool final_size_over_budget = false;
    if (ok && !kv_cache_file_size_fits(kc, (uint64_t)text_len, payload_bytes,
                                       tool_map_bytes,
                                       &final_file_bytes, &final_required_bytes))
    {
        final_size_over_budget = true;
        ok = false;
    }
    if (ok && rename(tmp, path) != 0) {
        saved_errno = errno;
        ok = false;
    }
    const double save_ms = (now_sec() - save_t0) * 1000.0;
    if (!ok) {
        if (final_size_over_budget) {
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache skipped tokens=%d reason=%s because final file size %.2f MiB (%.2f MiB with safety) exceeds budget %.2f MiB save=%.1f ms",
                       store_tokens.len,
                       reason,
                       (double)final_file_bytes / (1024.0 * 1024.0),
                       (double)final_required_bytes / (1024.0 * 1024.0),
                       (double)kc->budget_bytes / (1024.0 * 1024.0),
                       save_ms);
        } else {
            server_log(DS4_LOG_KVCACHE, "ds4-server: kv cache store failed (%s): %s save=%.1f ms",
                       reason,
                       saved_errno ? strerror(saved_errno) : (err[0] ? err : "unknown error"),
                       save_ms);
        }
        unlink(tmp);
    } else {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: kv cache stored tokens=%d trimmed=%d reason=%s key=%s size=%.2f MiB save=%.1f ms",
                   store_tokens.len,
                   original_len - store_tokens.len,
                   reason,
                   text_override ? (cache_text_key ? cache_text_key : "visible-transcript") : "token-text",
```

<｜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
(uint32_t)store_tokens.len, 0,
                   (uint32_t)ds4_session_ctx(s->session), now, now, payload_bytes);
    uint8_t tb[4];
    le_put32(tb, (uint32_t)text_len);
    uint64_t tool_map_bytes = 0;
    errno = 0;
    bool ok = fwrite(h, 1, sizeof(h), fp) == sizeof(h) &&
              fwrite(tb, 1, sizeof(tb), fp) == sizeof(tb) &&
              fwrite(text, 1, text_len, fp) == text_len &&
              ds4_session_save_payload(s->session, fp, err, sizeof(err)) == 0 &&
              kv_tool_map_write(s, fp, text, &tool_map_bytes) &&
              fflush(fp) == 0;
    int saved_errno = errno;
    if (fclose(fp) != 0) {
        if (!saved_errno) saved_errno = errno;
        ok = false;
    }
    uint64_t final_file_bytes = 0, final_required_bytes = 0;
    bool final_size_over_budget = false;
    if (ok && !kv_cache_file_size_fits(kc, (uint64_t)text_len, payload_bytes,
                                       tool_map_bytes,
                                       &final_file_bytes, &final_required_bytes))
    {
        final_size_over_budget = true;
        ok = false;
    }
    if (ok && rename(tmp, path) != 0) {
        saved_errno = errno;
        ok = false;
    }
    const double save_ms = (now_sec() - save_t0) * 1000.0;
    if (!ok) {
        if (final_size_over_budget) {
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache skipped tokens=%d reason=%s because final file size %.2f MiB (%.2f MiB with safety) exceeds budget %.2f MiB save=%.1f ms",
                       store_tokens.len,
                       reason,
                       (double)final_file_bytes / (1024.0 * 1024.0),
                       (double)final_required_bytes / (1024.0 * 1024.0),
                       (double)kc->budget_bytes / (1024.0 * 1024.0),
                       save_ms);
        } else {
            server_log(DS4_LOG_KVCACHE, "ds4-server: kv cache store failed (%s): %s save=%.1f ms",
                       reason,
                       saved_errno ? strerror(saved_errno) : (err[0] ? err : "unknown error"),
                       save_ms);
        }
        unlink(tmp);
    } else {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: kv cache stored tokens=%d trimmed=%d reason=%s key=%s size=%.2f MiB save=%.1f ms",
                   store_tokens.len,
                   original_len - store_tokens.len,
                   reason,
                   text_override ? (cache_text_key ? cache_text_key : "visible-transcript") : "token-text",
```<｜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
(uint32_t)store_tokens.len, 0,
                   (uint32_t)ds4_session_ctx(s->session), now, now, payload_bytes);
    uint8_t tb[4];
    le_put32(tb, (uint32_t)text_len);
    uint64_t tool_map_bytes = 0;
    errno = 0;
    bool ok = fwrite(h, 1, sizeof(h), fp) == sizeof(h) &&
              fwrite(tb, 1, sizeof(tb), fp) == sizeof(tb) &&
              fwrite(text, 1, text_len, fp) == text_len &&
              ds4_session_save_payload(s->session, fp, err, sizeof(err)) == 0 &&
              kv_tool_map_write(s, fp, text, &tool_map_bytes) &&
              fflush(fp) == 0;
    int saved_errno = errno;
    if (fclose(fp) != 0) {
        if (!saved_errno) saved_errno = errno;
        ok = false;
    }
    uint64_t final_file_bytes = 0, final_required_bytes = 0;
    bool final_size_over_budget = false;
    if (ok && !kv_cache_file_size_fits(kc, (uint64_t)text_len, payload_bytes,
                                       tool_map_bytes,
                                       &final_file_bytes, &final_required_bytes))
    {
        final_size_over_budget = true;
        ok = false;
    }
    if (ok && rename(tmp, path) != 0) {
        saved_errno = errno;
        ok = false;
    }
    const double save_ms = (now_sec() - save_t0) * 1000.0;
    if (!ok) {
        if (final_size_over_budget) {
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache skipped tokens=%d reason=%s because final file size %.2f MiB (%.2f MiB with safety) exceeds budget %.2f MiB save=%.1f ms",
                       store_tokens.len,
                       reason,
                       (double)final_file_bytes / (1024.0 * 1024.0),
                       (double)final_required_bytes / (1024.0 * 1024.0),
                       (double)kc->budget_bytes / (1024.0 * 1024.0),
                       save_ms);
        } else {
            server_log(DS4_LOG_KVCACHE, "ds4-server: kv cache store failed (%s): %s save=%.1f ms",
                       reason,
                       saved_errno ? strerror(saved_errno) : (err[0] ? err : "unknown error"),
                       save_ms);
        }
        unlink(tmp);
    } else {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: kv cache stored tokens=%d trimmed=%d reason=%s key=%s size=%.2f MiB save=%.1f ms",
                   store_tokens.len,
                   original_len - store_tokens.len,
                   reason,
                   text_override ? (cache_text_key ? cache_text_key : "visible-transcript") : "token-text",
```

<｜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
(uint32_t)store_tokens.len, 0,
                   (uint32_t)ds4_session_ctx(s->session), now, now, payload_bytes);
    uint8_t tb[4];
    le_put32(tb, (uint32_t)text_len);
    uint64_t tool_map_bytes = 0;
    errno = 0;
    bool ok = fwrite(h, 1, sizeof(h), fp) == sizeof(h) &&
              fwrite(tb, 1, sizeof(tb), fp) == sizeof(tb) &&
              fwrite(text, 1, text_len, fp) == text_len &&
              ds4_session_save_payload(s->session, fp, err, sizeof(err)) == 0 &&
              kv_tool_map_write(s, fp, text, &tool_map_bytes) &&
              fflush(fp) == 0;
    int saved_errno = errno;
    if (fclose(fp) != 0) {
        if (!saved_errno) saved_errno = errno;
        ok = false;
    }
    uint64_t final_file_bytes = 0, final_required_bytes = 0;
    bool final_size_over_budget = false;
    if (ok && !kv_cache_file_size_fits(kc, (uint64_t)text_len, payload_bytes,
                                       tool_map_bytes,
                                       &final_file_bytes, &final_required_bytes))
    {
        final_size_over_budget = true;
        ok = false;
    }
    if (ok && rename(tmp, path) != 0) {
        saved_errno = errno;
        ok = false;
    }
    const double save_ms = (now_sec() - save_t0) * 1000.0;
    if (!ok) {
        if (final_size_over_budget) {
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache skipped tokens=%d reason=%s because final file size %.2f MiB (%.2f MiB with safety) exceeds budget %.2f MiB save=%.1f ms",
                       store_tokens.len,
                       reason,
                       (double)final_file_bytes / (1024.0 * 1024.0),
                       (double)final_required_bytes / (1024.0 * 1024.0),
                       (double)kc->budget_bytes / (1024.0 * 1024.0),
                       save_ms);
        } else {
            server_log(DS4_LOG_KVCACHE, "ds4-server: kv cache store failed (%s): %s save=%.1f ms",
                       reason,
                       saved_errno ? strerror(saved_errno) : (err[0] ? err : "unknown error"),
                       save_ms);
        }
        unlink(tmp);
    } else {
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: kv cache stored tokens=%d trimmed=%d reason=%s key=%s size=%.2f MiB save=%.1f ms",
                   store_tokens.len,
                   original_len - store_tokens.len,
                   reason,
                   text_override ? (cache_text_key ? cache_text_key : "visible-transcript") : "token-text",
```<｜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
original_len - store_tokens.len,
                   reason,
                   text_override ? (cache_text_key ? cache_text_key : "visible-transcript") : "token-text",
                   (double)(KV_CACHE_FIXED_HEADER + 4ull + text_len + payload_bytes + tool_map_bytes) / (1024.0 * 1024.0),
                   save_ms);
        kv_cache_evict(kc, live_tokens, sha);
    }
    free(tmp);
    free(text);
    free(path);
    ds4_tokens_free(&store_tokens);
    return ok;
}

static bool kv_cache_store_live_prefix(server *s, const ds4_tokens *tokens,
                                       int store_len, const char *reason) {
    return kv_cache_store_live_prefix_text(s, tokens, store_len, reason,
                                           NULL, 0, NULL);
}

static void kv_cache_store_current(server *s, const char *reason) {
    const ds4_tokens *tokens = ds4_session_tokens(s->session);
    if (!tokens) return;

    char *visible_text = NULL;
    uint8_t visible_ext = 0;
    const char *visible_key = NULL;
    pthread_mutex_lock(&s->tool_mu);
    if (s->responses_live.valid &&
        s->responses_live.live_tokens == tokens->len &&
        s->responses_live.visible_text &&
        s->responses_live.visible_text[0])
    {
        visible_text = xstrdup(s->responses_live.visible_text);
        visible_ext = KV_EXT_RESPONSES_VISIBLE;
        visible_key = "responses-visible";
    } else if (s->thinking_live.valid &&
               s->thinking_live.live_tokens == tokens->len &&
               s->thinking_live.visible_text &&
               s->thinking_live.visible_text[0])
    {
        visible_text = xstrdup(s->thinking_live.visible_text);
        visible_ext = KV_EXT_THINKING_VISIBLE;
        visible_key = "thinking-visible";
    }
    pthread_mutex_unlock(&s->tool_mu);

    /* A visible live checkpoint can contain hidden reasoning that the client
     * intentionally does not replay.  For disk recovery after a session switch,
     * key that payload by the visible protocol transcript, not by rendering the
     * hidden sampled tokens.  On load, DS4 restores the hidden KV payload and
     * tokenizes only the visible suffix that follows this key. */
    if (visible_text) {
        kv_cache_store_live_prefix_text(s, tokens, tokens->len, reason,
                                        visible_text, visible_ext, visible_key);
        free(visible_text);
    } else {
        kv_cache_store_live_prefix(s, tokens, tokens->len, reason);
    }
}

static void kv_cache_note_store(kv_disk_cache *kc, int tokens) {
```

<｜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
original_len - store_tokens.len,
                   reason,
                   text_override ? (cache_text_key ? cache_text_key : "visible-transcript") : "token-text",
                   (double)(KV_CACHE_FIXED_HEADER + 4ull + text_len + payload_bytes + tool_map_bytes) / (1024.0 * 1024.0),
                   save_ms);
        kv_cache_evict(kc, live_tokens, sha);
    }
    free(tmp);
    free(text);
    free(path);
    ds4_tokens_free(&store_tokens);
    return ok;
}

static bool kv_cache_store_live_prefix(server *s, const ds4_tokens *tokens,
                                       int store_len, const char *reason) {
    return kv_cache_store_live_prefix_text(s, tokens, store_len, reason,
                                           NULL, 0, NULL);
}

static void kv_cache_store_current(server *s, const char *reason) {
    const ds4_tokens *tokens = ds4_session_tokens(s->session);
    if (!tokens) return;

    char *visible_text = NULL;
    uint8_t visible_ext = 0;
    const char *visible_key = NULL;
    pthread_mutex_lock(&s->tool_mu);
    if (s->responses_live.valid &&
        s->responses_live.live_tokens == tokens->len &&
        s->responses_live.visible_text &&
        s->responses_live.visible_text[0])
    {
        visible_text = xstrdup(s->responses_live.visible_text);
        visible_ext = KV_EXT_RESPONSES_VISIBLE;
        visible_key = "responses-visible";
    } else if (s->thinking_live.valid &&
               s->thinking_live.live_tokens == tokens->len &&
               s->thinking_live.visible_text &&
               s->thinking_live.visible_text[0])
    {
        visible_text = xstrdup(s->thinking_live.visible_text);
        visible_ext = KV_EXT_THINKING_VISIBLE;
        visible_key = "thinking-visible";
    }
    pthread_mutex_unlock(&s->tool_mu);

    /* A visible live checkpoint can contain hidden reasoning that the client
     * intentionally does not replay.  For disk recovery after a session switch,
     * key that payload by the visible protocol transcript, not by rendering the
     * hidden sampled tokens.  On load, DS4 restores the hidden KV payload and
     * tokenizes only the visible suffix that follows this key. */
    if (visible_text) {
        kv_cache_store_live_prefix_text(s, tokens, tokens->len, reason,
                                        visible_text, visible_ext, visible_key);
        free(visible_text);
    } else {
        kv_cache_store_live_prefix(s, tokens, tokens->len, reason);
    }
}

static void kv_cache_note_store(kv_disk_cache *kc, int tokens) {
```<｜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
original_len - store_tokens.len,
                   reason,
                   text_override ? (cache_text_key ? cache_text_key : "visible-transcript") : "token-text",
                   (double)(KV_CACHE_FIXED_HEADER + 4ull + text_len + payload_bytes + tool_map_bytes) / (1024.0 * 1024.0),
                   save_ms);
        kv_cache_evict(kc, live_tokens, sha);
    }
    free(tmp);
    free(text);
    free(path);
    ds4_tokens_free(&store_tokens);
    return ok;
}

static bool kv_cache_store_live_prefix(server *s, const ds4_tokens *tokens,
                                       int store_len, const char *reason) {
    return kv_cache_store_live_prefix_text(s, tokens, store_len, reason,
                                           NULL, 0, NULL);
}

static void kv_cache_store_current(server *s, const char *reason) {
    const ds4_tokens *tokens = ds4_session_tokens(s->session);
    if (!tokens) return;

    char *visible_text = NULL;
    uint8_t visible_ext = 0;
    const char *visible_key = NULL;
    pthread_mutex_lock(&s->tool_mu);
    if (s->responses_live.valid &&
        s->responses_live.live_tokens == tokens->len &&
        s->responses_live.visible_text &&
        s->responses_live.visible_text[0])
    {
        visible_text = xstrdup(s->responses_live.visible_text);
        visible_ext = KV_EXT_RESPONSES_VISIBLE;
        visible_key = "responses-visible";
    } else if (s->thinking_live.valid &&
               s->thinking_live.live_tokens == tokens->len &&
               s->thinking_live.visible_text &&
               s->thinking_live.visible_text[0])
    {
        visible_text = xstrdup(s->thinking_live.visible_text);
        visible_ext = KV_EXT_THINKING_VISIBLE;
        visible_key = "thinking-visible";
    }
    pthread_mutex_unlock(&s->tool_mu);

    /* A visible live checkpoint can contain hidden reasoning that the client
     * intentionally does not replay.  For disk recovery after a session switch,
     * key that payload by the visible protocol transcript, not by rendering the
     * hidden sampled tokens.  On load, DS4 restores the hidden KV payload and
     * tokenizes only the visible suffix that follows this key. */
    if (visible_text) {
        kv_cache_store_live_prefix_text(s, tokens, tokens->len, reason,
                                        visible_text, visible_ext, visible_key);
        free(visible_text);
    } else {
        kv_cache_store_live_prefix(s, tokens, tokens->len, reason);
    }
}

static void kv_cache_note_store(kv_disk_cache *kc, int tokens) {
```

<｜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
original_len - store_tokens.len,
                   reason,
                   text_override ? (cache_text_key ? cache_text_key : "visible-transcript") : "token-text",
                   (double)(KV_CACHE_FIXED_HEADER + 4ull + text_len + payload_bytes + tool_map_bytes) / (1024.0 * 1024.0),
                   save_ms);
        kv_cache_evict(kc, live_tokens, sha);
    }
    free(tmp);
    free(text);
    free(path);
    ds4_tokens_free(&store_tokens);
    return ok;
}

static bool kv_cache_store_live_prefix(server *s, const ds4_tokens *tokens,
                                       int store_len, const char *reason) {
    return kv_cache_store_live_prefix_text(s, tokens, store_len, reason,
                                           NULL, 0, NULL);
}

static void kv_cache_store_current(server *s, const char *reason) {
    const ds4_tokens *tokens = ds4_session_tokens(s->session);
    if (!tokens) return;

    char *visible_text = NULL;
    uint8_t visible_ext = 0;
    const char *visible_key = NULL;
    pthread_mutex_lock(&s->tool_mu);
    if (s->responses_live.valid &&
        s->responses_live.live_tokens == tokens->len &&
        s->responses_live.visible_text &&
        s->responses_live.visible_text[0])
    {
        visible_text = xstrdup(s->responses_live.visible_text);
        visible_ext = KV_EXT_RESPONSES_VISIBLE;
        visible_key = "responses-visible";
    } else if (s->thinking_live.valid &&
               s->thinking_live.live_tokens == tokens->len &&
               s->thinking_live.visible_text &&
               s->thinking_live.visible_text[0])
    {
        visible_text = xstrdup(s->thinking_live.visible_text);
        visible_ext = KV_EXT_THINKING_VISIBLE;
        visible_key = "thinking-visible";
    }
    pthread_mutex_unlock(&s->tool_mu);

    /* A visible live checkpoint can contain hidden reasoning that the client
     * intentionally does not replay.  For disk recovery after a session switch,
     * key that payload by the visible protocol transcript, not by rendering the
     * hidden sampled tokens.  On load, DS4 restores the hidden KV payload and
     * tokenizes only the visible suffix that follows this key. */
    if (visible_text) {
        kv_cache_store_live_prefix_text(s, tokens, tokens->len, reason,
                                        visible_text, visible_ext, visible_key);
        free(visible_text);
    } else {
        kv_cache_store_live_prefix(s, tokens, tokens->len, reason);
    }
}

static void kv_cache_note_store(kv_disk_cache *kc, int tokens) {
```<｜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
free(visible_text);
    } else {
        kv_cache_store_live_prefix(s, tokens, tokens->len, reason);
    }
}

static void kv_cache_note_store(kv_disk_cache *kc, int tokens) {
    if (tokens > kc->continued_last_store_tokens) {
        kc->continued_last_store_tokens = tokens;
    }
}

static int kv_cache_suppress_continued_store(kv_disk_cache *kc, int tokens) {
    if (kv_cache_continued_store_target(kc, tokens) != tokens) return -1;
    int old = kc->continued_last_store_tokens;
    kv_cache_note_store(kc, tokens);
    return old;
}

static void kv_cache_restore_suppressed_continued(kv_disk_cache *kc,
                                                  int old_tokens,
                                                  int suppressed_tokens) {
    if (old_tokens >= 0 && kc->continued_last_store_tokens == suppressed_tokens) {
        kc->continued_last_store_tokens = old_tokens;
    }
}

static void kv_cache_maybe_store_continued(server *s) {
    kv_disk_cache *kc = &s->kv;
    const ds4_tokens *tokens = ds4_session_tokens(s->session);
    if (!tokens) return;
    const int target = kv_cache_continued_store_target(kc, tokens->len);
    if (target == 0) return;
    if (kv_cache_store_live_prefix(s, tokens, target, "continued")) {
        kv_cache_note_store(kc, target);
    }
}

static int kv_cache_find_text_prefix(kv_disk_cache *kc, const char *prompt_text,
                                     int quant_bits, int ctx_size) {
    if (!prompt_text) return -1;
    const size_t prompt_bytes = strlen(prompt_text);
    kv_cache_refresh(kc);
    int best = -1;
    for (int i = 0; i < kc->len; i++) {
        kv_entry *e = &kc->entry[i];
        if (e->text_bytes > prompt_bytes || e->text_bytes > SIZE_MAX) continue;
        if ((int)e->tokens < kc->opt.min_tokens) continue;
        if ((uint32_t)ctx_size < e->ctx_size) continue;
        if (kc->reject_different_quant && e->quant_bits != (uint8_t)quant_bits) continue;
        if (best >= 0) {
            kv_entry *b = &kc->entry[best];
            if (e->text_bytes < b->text_bytes) continue;
            if (e->text_bytes == b->text_bytes && e->tokens <= b->tokens) continue;
        }
        char sha[41];
        sha1_bytes_hex(prompt_text, (size_t)e->text_bytes, sha);
        if (!strcmp(sha, e->sha)) best = i;
    }
    return best;
}

static int kv_cache_try_load_text(server *s, const char *prompt_text,
                                  ds4_tokens *effective_prompt,
                                  char **loaded_path_out,
                                  uint8_t *loaded_ext_flags_out,
```

<｜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
free(visible_text);
    } else {
        kv_cache_store_live_prefix(s, tokens, tokens->len, reason);
    }
}

static void kv_cache_note_store(kv_disk_cache *kc, int tokens) {
    if (tokens > kc->continued_last_store_tokens) {
        kc->continued_last_store_tokens = tokens;
    }
}

static int kv_cache_suppress_continued_store(kv_disk_cache *kc, int tokens) {
    if (kv_cache_continued_store_target(kc, tokens) != tokens) return -1;
    int old = kc->continued_last_store_tokens;
    kv_cache_note_store(kc, tokens);
    return old;
}

static void kv_cache_restore_suppressed_continued(kv_disk_cache *kc,
                                                  int old_tokens,
                                                  int suppressed_tokens) {
    if (old_tokens >= 0 && kc->continued_last_store_tokens == suppressed_tokens) {
        kc->continued_last_store_tokens = old_tokens;
    }
}

static void kv_cache_maybe_store_continued(server *s) {
    kv_disk_cache *kc = &s->kv;
    const ds4_tokens *tokens = ds4_session_tokens(s->session);
    if (!tokens) return;
    const int target = kv_cache_continued_store_target(kc, tokens->len);
    if (target == 0) return;
    if (kv_cache_store_live_prefix(s, tokens, target, "continued")) {
        kv_cache_note_store(kc, target);
    }
}

static int kv_cache_find_text_prefix(kv_disk_cache *kc, const char *prompt_text,
                                     int quant_bits, int ctx_size) {
    if (!prompt_text) return -1;
    const size_t prompt_bytes = strlen(prompt_text);
    kv_cache_refresh(kc);
    int best = -1;
    for (int i = 0; i < kc->len; i++) {
        kv_entry *e = &kc->entry[i];
        if (e->text_bytes > prompt_bytes || e->text_bytes > SIZE_MAX) continue;
        if ((int)e->tokens < kc->opt.min_tokens) continue;
        if ((uint32_t)ctx_size < e->ctx_size) continue;
        if (kc->reject_different_quant && e->quant_bits != (uint8_t)quant_bits) continue;
        if (best >= 0) {
            kv_entry *b = &kc->entry[best];
            if (e->text_bytes < b->text_bytes) continue;
            if (e->text_bytes == b->text_bytes && e->tokens <= b->tokens) continue;
        }
        char sha[41];
        sha1_bytes_hex(prompt_text, (size_t)e->text_bytes, sha);
        if (!strcmp(sha, e->sha)) best = i;
    }
    return best;
}

static int kv_cache_try_load_text(server *s, const char *prompt_text,
                                  ds4_tokens *effective_prompt,
                                  char **loaded_path_out,
                                  uint8_t *loaded_ext_flags_out,
```<｜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
free(visible_text);
    } else {
        kv_cache_store_live_prefix(s, tokens, tokens->len, reason);
    }
}

static void kv_cache_note_store(kv_disk_cache *kc, int tokens) {
    if (tokens > kc->continued_last_store_tokens) {
        kc->continued_last_store_tokens = tokens;
    }
}

static int kv_cache_suppress_continued_store(kv_disk_cache *kc, int tokens) {
    if (kv_cache_continued_store_target(kc, tokens) != tokens) return -1;
    int old = kc->continued_last_store_tokens;
    kv_cache_note_store(kc, tokens);
    return old;
}

static void kv_cache_restore_suppressed_continued(kv_disk_cache *kc,
                                                  int old_tokens,
                                                  int suppressed_tokens) {
    if (old_tokens >= 0 && kc->continued_last_store_tokens == suppressed_tokens) {
        kc->continued_last_store_tokens = old_tokens;
    }
}

static void kv_cache_maybe_store_continued(server *s) {
    kv_disk_cache *kc = &s->kv;
    const ds4_tokens *tokens = ds4_session_tokens(s->session);
    if (!tokens) return;
    const int target = kv_cache_continued_store_target(kc, tokens->len);
    if (target == 0) return;
    if (kv_cache_store_live_prefix(s, tokens, target, "continued")) {
        kv_cache_note_store(kc, target);
    }
}

static int kv_cache_find_text_prefix(kv_disk_cache *kc, const char *prompt_text,
                                     int quant_bits, int ctx_size) {
    if (!prompt_text) return -1;
    const size_t prompt_bytes = strlen(prompt_text);
    kv_cache_refresh(kc);
    int best = -1;
    for (int i = 0; i < kc->len; i++) {
        kv_entry *e = &kc->entry[i];
        if (e->text_bytes > prompt_bytes || e->text_bytes > SIZE_MAX) continue;
        if ((int)e->tokens < kc->opt.min_tokens) continue;
        if ((uint32_t)ctx_size < e->ctx_size) continue;
        if (kc->reject_different_quant && e->quant_bits != (uint8_t)quant_bits) continue;
        if (best >= 0) {
            kv_entry *b = &kc->entry[best];
            if (e->text_bytes < b->text_bytes) continue;
            if (e->text_bytes == b->text_bytes && e->tokens <= b->tokens) continue;
        }
        char sha[41];
        sha1_bytes_hex(prompt_text, (size_t)e->text_bytes, sha);
        if (!strcmp(sha, e->sha)) best = i;
    }
    return best;
}

static int kv_cache_try_load_text(server *s, const char *prompt_text,
                                  ds4_tokens *effective_prompt,
                                  char **loaded_path_out,
                                  uint8_t *loaded_ext_flags_out,
```

<｜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
free(visible_text);
    } else {
        kv_cache_store_live_prefix(s, tokens, tokens->len, reason);
    }
}

static void kv_cache_note_store(kv_disk_cache *kc, int tokens) {
    if (tokens > kc->continued_last_store_tokens) {
        kc->continued_last_store_tokens = tokens;
    }
}

static int kv_cache_suppress_continued_store(kv_disk_cache *kc, int tokens) {
    if (kv_cache_continued_store_target(kc, tokens) != tokens) return -1;
    int old = kc->continued_last_store_tokens;
    kv_cache_note_store(kc, tokens);
    return old;
}

static void kv_cache_restore_suppressed_continued(kv_disk_cache *kc,
                                                  int old_tokens,
                                                  int suppressed_tokens) {
    if (old_tokens >= 0 && kc->continued_last_store_tokens == suppressed_tokens) {
        kc->continued_last_store_tokens = old_tokens;
    }
}

static void kv_cache_maybe_store_continued(server *s) {
    kv_disk_cache *kc = &s->kv;
    const ds4_tokens *tokens = ds4_session_tokens(s->session);
    if (!tokens) return;
    const int target = kv_cache_continued_store_target(kc, tokens->len);
    if (target == 0) return;
    if (kv_cache_store_live_prefix(s, tokens, target, "continued")) {
        kv_cache_note_store(kc, target);
    }
}

static int kv_cache_find_text_prefix(kv_disk_cache *kc, const char *prompt_text,
                                     int quant_bits, int ctx_size) {
    if (!prompt_text) return -1;
    const size_t prompt_bytes = strlen(prompt_text);
    kv_cache_refresh(kc);
    int best = -1;
    for (int i = 0; i < kc->len; i++) {
        kv_entry *e = &kc->entry[i];
        if (e->text_bytes > prompt_bytes || e->text_bytes > SIZE_MAX) continue;
        if ((int)e->tokens < kc->opt.min_tokens) continue;
        if ((uint32_t)ctx_size < e->ctx_size) continue;
        if (kc->reject_different_quant && e->quant_bits != (uint8_t)quant_bits) continue;
        if (best >= 0) {
            kv_entry *b = &kc->entry[best];
            if (e->text_bytes < b->text_bytes) continue;
            if (e->text_bytes == b->text_bytes && e->tokens <= b->tokens) continue;
        }
        char sha[41];
        sha1_bytes_hex(prompt_text, (size_t)e->text_bytes, sha);
        if (!strcmp(sha, e->sha)) best = i;
    }
    return best;
}

static int kv_cache_try_load_text(server *s, const char *prompt_text,
                                  ds4_tokens *effective_prompt,
                                  char **loaded_path_out,
                                  uint8_t *loaded_ext_flags_out,
```<｜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
ds4_tokens *effective_prompt,
                                  char **loaded_path_out,
                                  uint8_t *loaded_ext_flags_out,
                                  bool responses_protocol) {
    if (loaded_path_out) *loaded_path_out = NULL;
    if (loaded_ext_flags_out) *loaded_ext_flags_out = 0;
    if (effective_prompt) effective_prompt->len = 0;
    kv_disk_cache *kc = &s->kv;
    if (!kc->enabled || !prompt_text) return 0;
    const int quant_bits = ds4_engine_routed_quant_bits(s->engine);
    if (quant_bits != 2 && quant_bits != 4) return 0;
    const size_t prompt_bytes = strlen(prompt_text);
    int idx = kv_cache_find_text_prefix(kc, prompt_text, quant_bits,
                                        ds4_session_ctx(s->session));
    if (idx < 0) return 0;

    kv_entry e = kc->entry[idx];
    char *path = xstrdup(e.path);
    const double load_t0 = now_sec();
    FILE *fp = fopen(path, "rb");
    if (!fp) {
        free(path);
        return 0;
    }
    uint32_t text_bytes = 0;
    kv_entry hdr = {0};
    const char *fail_reason = "invalid header";
    bool header_ok = kv_read_header(fp, &hdr, &text_bytes);
    char *cached_text = NULL;
    if (header_ok) {
        if ((uint64_t)text_bytes > prompt_bytes) {
            header_ok = false;
            fail_reason = "cached text is longer than prompt";
        } else {
            cached_text = xmalloc((size_t)text_bytes + 1);
            if (fread(cached_text, 1, text_bytes, fp) != text_bytes) {
                header_ok = false;
                fail_reason = "truncated cached text";
            } else {
                cached_text[text_bytes] = '\0';
                char text_sha[41];
                sha1_bytes_hex(cached_text, text_bytes, text_sha);
                if (strcmp(text_sha, e.sha)) {
                    header_ok = false;
                    fail_reason = "cached text hash mismatch";
                } else if (!byte_prefix_match(prompt_text, prompt_bytes,
                                              cached_text, text_bytes)) {
                    header_ok = false;
                    fail_reason = "cached text prefix mismatch";
                }
            }
        }
    }
    char err[160] = {0};
    int loaded = 0;
    if (header_ok && ds4_session_load_payload(s->session, fp, hdr.payload_bytes, err, sizeof(err)) == 0) {
        const ds4_tokens *loaded_tokens = ds4_session_tokens(s->session);
        if (loaded_tokens && loaded_tokens->len == (int)hdr.tokens) {
            loaded = (int)hdr.tokens;
```

<｜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
ds4_tokens *effective_prompt,
                                  char **loaded_path_out,
                                  uint8_t *loaded_ext_flags_out,
                                  bool responses_protocol) {
    if (loaded_path_out) *loaded_path_out = NULL;
    if (loaded_ext_flags_out) *loaded_ext_flags_out = 0;
    if (effective_prompt) effective_prompt->len = 0;
    kv_disk_cache *kc = &s->kv;
    if (!kc->enabled || !prompt_text) return 0;
    const int quant_bits = ds4_engine_routed_quant_bits(s->engine);
    if (quant_bits != 2 && quant_bits != 4) return 0;
    const size_t prompt_bytes = strlen(prompt_text);
    int idx = kv_cache_find_text_prefix(kc, prompt_text, quant_bits,
                                        ds4_session_ctx(s->session));
    if (idx < 0) return 0;

    kv_entry e = kc->entry[idx];
    char *path = xstrdup(e.path);
    const double load_t0 = now_sec();
    FILE *fp = fopen(path, "rb");
    if (!fp) {
        free(path);
        return 0;
    }
    uint32_t text_bytes = 0;
    kv_entry hdr = {0};
    const char *fail_reason = "invalid header";
    bool header_ok = kv_read_header(fp, &hdr, &text_bytes);
    char *cached_text = NULL;
    if (header_ok) {
        if ((uint64_t)text_bytes > prompt_bytes) {
            header_ok = false;
            fail_reason = "cached text is longer than prompt";
        } else {
            cached_text = xmalloc((size_t)text_bytes + 1);
            if (fread(cached_text, 1, text_bytes, fp) != text_bytes) {
                header_ok = false;
                fail_reason = "truncated cached text";
            } else {
                cached_text[text_bytes] = '\0';
                char text_sha[41];
                sha1_bytes_hex(cached_text, text_bytes, text_sha);
                if (strcmp(text_sha, e.sha)) {
                    header_ok = false;
                    fail_reason = "cached text hash mismatch";
                } else if (!byte_prefix_match(prompt_text, prompt_bytes,
                                              cached_text, text_bytes)) {
                    header_ok = false;
                    fail_reason = "cached text prefix mismatch";
                }
            }
        }
    }
    char err[160] = {0};
    int loaded = 0;
    if (header_ok && ds4_session_load_payload(s->session, fp, hdr.payload_bytes, err, sizeof(err)) == 0) {
        const ds4_tokens *loaded_tokens = ds4_session_tokens(s->session);
        if (loaded_tokens && loaded_tokens->len == (int)hdr.tokens) {
            loaded = (int)hdr.tokens;
```<｜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
ds4_tokens *effective_prompt,
                                  char **loaded_path_out,
                                  uint8_t *loaded_ext_flags_out,
                                  bool responses_protocol) {
    if (loaded_path_out) *loaded_path_out = NULL;
    if (loaded_ext_flags_out) *loaded_ext_flags_out = 0;
    if (effective_prompt) effective_prompt->len = 0;
    kv_disk_cache *kc = &s->kv;
    if (!kc->enabled || !prompt_text) return 0;
    const int quant_bits = ds4_engine_routed_quant_bits(s->engine);
    if (quant_bits != 2 && quant_bits != 4) return 0;
    const size_t prompt_bytes = strlen(prompt_text);
    int idx = kv_cache_find_text_prefix(kc, prompt_text, quant_bits,
                                        ds4_session_ctx(s->session));
    if (idx < 0) return 0;

    kv_entry e = kc->entry[idx];
    char *path = xstrdup(e.path);
    const double load_t0 = now_sec();
    FILE *fp = fopen(path, "rb");
    if (!fp) {
        free(path);
        return 0;
    }
    uint32_t text_bytes = 0;
    kv_entry hdr = {0};
    const char *fail_reason = "invalid header";
    bool header_ok = kv_read_header(fp, &hdr, &text_bytes);
    char *cached_text = NULL;
    if (header_ok) {
        if ((uint64_t)text_bytes > prompt_bytes) {
            header_ok = false;
            fail_reason = "cached text is longer than prompt";
        } else {
            cached_text = xmalloc((size_t)text_bytes + 1);
            if (fread(cached_text, 1, text_bytes, fp) != text_bytes) {
                header_ok = false;
                fail_reason = "truncated cached text";
            } else {
                cached_text[text_bytes] = '\0';
                char text_sha[41];
                sha1_bytes_hex(cached_text, text_bytes, text_sha);
                if (strcmp(text_sha, e.sha)) {
                    header_ok = false;
                    fail_reason = "cached text hash mismatch";
                } else if (!byte_prefix_match(prompt_text, prompt_bytes,
                                              cached_text, text_bytes)) {
                    header_ok = false;
                    fail_reason = "cached text prefix mismatch";
                }
            }
        }
    }
    char err[160] = {0};
    int loaded = 0;
    if (header_ok && ds4_session_load_payload(s->session, fp, hdr.payload_bytes, err, sizeof(err)) == 0) {
        const ds4_tokens *loaded_tokens = ds4_session_tokens(s->session);
        if (loaded_tokens && loaded_tokens->len == (int)hdr.tokens) {
            loaded = (int)hdr.tokens;
```

<｜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
ds4_tokens *effective_prompt,
                                  char **loaded_path_out,
                                  uint8_t *loaded_ext_flags_out,
                                  bool responses_protocol) {
    if (loaded_path_out) *loaded_path_out = NULL;
    if (loaded_ext_flags_out) *loaded_ext_flags_out = 0;
    if (effective_prompt) effective_prompt->len = 0;
    kv_disk_cache *kc = &s->kv;
    if (!kc->enabled || !prompt_text) return 0;
    const int quant_bits = ds4_engine_routed_quant_bits(s->engine);
    if (quant_bits != 2 && quant_bits != 4) return 0;
    const size_t prompt_bytes = strlen(prompt_text);
    int idx = kv_cache_find_text_prefix(kc, prompt_text, quant_bits,
                                        ds4_session_ctx(s->session));
    if (idx < 0) return 0;

    kv_entry e = kc->entry[idx];
    char *path = xstrdup(e.path);
    const double load_t0 = now_sec();
    FILE *fp = fopen(path, "rb");
    if (!fp) {
        free(path);
        return 0;
    }
    uint32_t text_bytes = 0;
    kv_entry hdr = {0};
    const char *fail_reason = "invalid header";
    bool header_ok = kv_read_header(fp, &hdr, &text_bytes);
    char *cached_text = NULL;
    if (header_ok) {
        if ((uint64_t)text_bytes > prompt_bytes) {
            header_ok = false;
            fail_reason = "cached text is longer than prompt";
        } else {
            cached_text = xmalloc((size_t)text_bytes + 1);
            if (fread(cached_text, 1, text_bytes, fp) != text_bytes) {
                header_ok = false;
                fail_reason = "truncated cached text";
            } else {
                cached_text[text_bytes] = '\0';
                char text_sha[41];
                sha1_bytes_hex(cached_text, text_bytes, text_sha);
                if (strcmp(text_sha, e.sha)) {
                    header_ok = false;
                    fail_reason = "cached text hash mismatch";
                } else if (!byte_prefix_match(prompt_text, prompt_bytes,
                                              cached_text, text_bytes)) {
                    header_ok = false;
                    fail_reason = "cached text prefix mismatch";
                }
            }
        }
    }
    char err[160] = {0};
    int loaded = 0;
    if (header_ok && ds4_session_load_payload(s->session, fp, hdr.payload_bytes, err, sizeof(err)) == 0) {
        const ds4_tokens *loaded_tokens = ds4_session_tokens(s->session);
        if (loaded_tokens && loaded_tokens->len == (int)hdr.tokens) {
            loaded = (int)hdr.tokens;
```<｜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
const ds4_tokens *loaded_tokens = ds4_session_tokens(s->session);
        if (loaded_tokens && loaded_tokens->len == (int)hdr.tokens) {
            loaded = (int)hdr.tokens;
            if (effective_prompt) {
                /* The cache lookup was by bytes, but the graph state is still
                 * the exact token history stored in the payload.  Build the
                 * prompt we give ds4_session_sync() from that exact history and
                 * tokenize only the text suffix after the byte prefix. */
                build_prompt_from_exact_prefix_and_text_suffix(
                    s->engine, loaded_tokens, prompt_text + text_bytes,
                    effective_prompt);
            }
            if (hdr.ext_flags & KV_EXT_TOOL_MAP) kv_tool_map_load_from_pos(s, fp, NULL);
        } else {
            ds4_session_invalidate(s->session);
            unlink(path);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache discarded corrupt text-prefix payload%s%s %s",
                       responses_protocol ? " " : "",
                       responses_protocol ? "RESPPROTO" : "",
                       path);
        }
    } else {
        if (header_ok) ds4_session_invalidate(s->session);
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: kv cache load failed%s%s %s: %s load=%.1f ms",
                   responses_protocol ? " " : "",
                   responses_protocol ? "RESPPROTO" : "",
                   path,
                   header_ok ? err : fail_reason,
                   (now_sec() - load_t0) * 1000.0);
    }
    fclose(fp);

    if (loaded > 0) {
        const double load_ms = (now_sec() - load_t0) * 1000.0;
        if (loaded_path_out) *loaded_path_out = xstrdup(path);
        if (loaded_ext_flags_out) *loaded_ext_flags_out = hdr.ext_flags;
        kc->continued_last_store_tokens = loaded;
        const char *key_kind = kv_cache_key_kind(hdr.ext_flags);
        if (kc->opt.cold_max_tokens > 0 && loaded > kc->opt.cold_max_tokens) {
            unlink(path);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache hit text%s%s tokens=%d text=%u quant=%u key=%s load=%.1f ms consumed file=%s",
                       responses_protocol ? " " : "",
                       responses_protocol ? "RESPPROTO" : "",
                       loaded, text_bytes, hdr.quant_bits, key_kind, load_ms, path);
        } else {
            kv_cache_touch_file(path, hdr.hits + 1);
            server_log(DS4_LOG_KVCACHE,
```

<｜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
const ds4_tokens *loaded_tokens = ds4_session_tokens(s->session);
        if (loaded_tokens && loaded_tokens->len == (int)hdr.tokens) {
            loaded = (int)hdr.tokens;
            if (effective_prompt) {
                /* The cache lookup was by bytes, but the graph state is still
                 * the exact token history stored in the payload.  Build the
                 * prompt we give ds4_session_sync() from that exact history and
                 * tokenize only the text suffix after the byte prefix. */
                build_prompt_from_exact_prefix_and_text_suffix(
                    s->engine, loaded_tokens, prompt_text + text_bytes,
                    effective_prompt);
            }
            if (hdr.ext_flags & KV_EXT_TOOL_MAP) kv_tool_map_load_from_pos(s, fp, NULL);
        } else {
            ds4_session_invalidate(s->session);
            unlink(path);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache discarded corrupt text-prefix payload%s%s %s",
                       responses_protocol ? " " : "",
                       responses_protocol ? "RESPPROTO" : "",
                       path);
        }
    } else {
        if (header_ok) ds4_session_invalidate(s->session);
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: kv cache load failed%s%s %s: %s load=%.1f ms",
                   responses_protocol ? " " : "",
                   responses_protocol ? "RESPPROTO" : "",
                   path,
                   header_ok ? err : fail_reason,
                   (now_sec() - load_t0) * 1000.0);
    }
    fclose(fp);

    if (loaded > 0) {
        const double load_ms = (now_sec() - load_t0) * 1000.0;
        if (loaded_path_out) *loaded_path_out = xstrdup(path);
        if (loaded_ext_flags_out) *loaded_ext_flags_out = hdr.ext_flags;
        kc->continued_last_store_tokens = loaded;
        const char *key_kind = kv_cache_key_kind(hdr.ext_flags);
        if (kc->opt.cold_max_tokens > 0 && loaded > kc->opt.cold_max_tokens) {
            unlink(path);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache hit text%s%s tokens=%d text=%u quant=%u key=%s load=%.1f ms consumed file=%s",
                       responses_protocol ? " " : "",
                       responses_protocol ? "RESPPROTO" : "",
                       loaded, text_bytes, hdr.quant_bits, key_kind, load_ms, path);
        } else {
            kv_cache_touch_file(path, hdr.hits + 1);
            server_log(DS4_LOG_KVCACHE,
```<｜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
const ds4_tokens *loaded_tokens = ds4_session_tokens(s->session);
        if (loaded_tokens && loaded_tokens->len == (int)hdr.tokens) {
            loaded = (int)hdr.tokens;
            if (effective_prompt) {
                /* The cache lookup was by bytes, but the graph state is still
                 * the exact token history stored in the payload.  Build the
                 * prompt we give ds4_session_sync() from that exact history and
                 * tokenize only the text suffix after the byte prefix. */
                build_prompt_from_exact_prefix_and_text_suffix(
                    s->engine, loaded_tokens, prompt_text + text_bytes,
                    effective_prompt);
            }
            if (hdr.ext_flags & KV_EXT_TOOL_MAP) kv_tool_map_load_from_pos(s, fp, NULL);
        } else {
            ds4_session_invalidate(s->session);
            unlink(path);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache discarded corrupt text-prefix payload%s%s %s",
                       responses_protocol ? " " : "",
                       responses_protocol ? "RESPPROTO" : "",
                       path);
        }
    } else {
        if (header_ok) ds4_session_invalidate(s->session);
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: kv cache load failed%s%s %s: %s load=%.1f ms",
                   responses_protocol ? " " : "",
                   responses_protocol ? "RESPPROTO" : "",
                   path,
                   header_ok ? err : fail_reason,
                   (now_sec() - load_t0) * 1000.0);
    }
    fclose(fp);

    if (loaded > 0) {
        const double load_ms = (now_sec() - load_t0) * 1000.0;
        if (loaded_path_out) *loaded_path_out = xstrdup(path);
        if (loaded_ext_flags_out) *loaded_ext_flags_out = hdr.ext_flags;
        kc->continued_last_store_tokens = loaded;
        const char *key_kind = kv_cache_key_kind(hdr.ext_flags);
        if (kc->opt.cold_max_tokens > 0 && loaded > kc->opt.cold_max_tokens) {
            unlink(path);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache hit text%s%s tokens=%d text=%u quant=%u key=%s load=%.1f ms consumed file=%s",
                       responses_protocol ? " " : "",
                       responses_protocol ? "RESPPROTO" : "",
                       loaded, text_bytes, hdr.quant_bits, key_kind, load_ms, path);
        } else {
            kv_cache_touch_file(path, hdr.hits + 1);
            server_log(DS4_LOG_KVCACHE,
```

<｜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
const ds4_tokens *loaded_tokens = ds4_session_tokens(s->session);
        if (loaded_tokens && loaded_tokens->len == (int)hdr.tokens) {
            loaded = (int)hdr.tokens;
            if (effective_prompt) {
                /* The cache lookup was by bytes, but the graph state is still
                 * the exact token history stored in the payload.  Build the
                 * prompt we give ds4_session_sync() from that exact history and
                 * tokenize only the text suffix after the byte prefix. */
                build_prompt_from_exact_prefix_and_text_suffix(
                    s->engine, loaded_tokens, prompt_text + text_bytes,
                    effective_prompt);
            }
            if (hdr.ext_flags & KV_EXT_TOOL_MAP) kv_tool_map_load_from_pos(s, fp, NULL);
        } else {
            ds4_session_invalidate(s->session);
            unlink(path);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache discarded corrupt text-prefix payload%s%s %s",
                       responses_protocol ? " " : "",
                       responses_protocol ? "RESPPROTO" : "",
                       path);
        }
    } else {
        if (header_ok) ds4_session_invalidate(s->session);
        server_log(DS4_LOG_KVCACHE,
                   "ds4-server: kv cache load failed%s%s %s: %s load=%.1f ms",
                   responses_protocol ? " " : "",
                   responses_protocol ? "RESPPROTO" : "",
                   path,
                   header_ok ? err : fail_reason,
                   (now_sec() - load_t0) * 1000.0);
    }
    fclose(fp);

    if (loaded > 0) {
        const double load_ms = (now_sec() - load_t0) * 1000.0;
        if (loaded_path_out) *loaded_path_out = xstrdup(path);
        if (loaded_ext_flags_out) *loaded_ext_flags_out = hdr.ext_flags;
        kc->continued_last_store_tokens = loaded;
        const char *key_kind = kv_cache_key_kind(hdr.ext_flags);
        if (kc->opt.cold_max_tokens > 0 && loaded > kc->opt.cold_max_tokens) {
            unlink(path);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache hit text%s%s tokens=%d text=%u quant=%u key=%s load=%.1f ms consumed file=%s",
                       responses_protocol ? " " : "",
                       responses_protocol ? "RESPPROTO" : "",
                       loaded, text_bytes, hdr.quant_bits, key_kind, load_ms, path);
        } else {
            kv_cache_touch_file(path, hdr.hits + 1);
            server_log(DS4_LOG_KVCACHE,
```<｜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
loaded, text_bytes, hdr.quant_bits, key_kind, load_ms, path);
        } else {
            kv_cache_touch_file(path, hdr.hits + 1);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache hit text%s%s tokens=%d text=%u quant=%u key=%s load=%.1f ms file=%s",
                       responses_protocol ? " " : "",
                       responses_protocol ? "RESPPROTO" : "",
                       loaded, text_bytes, hdr.quant_bits, key_kind, load_ms, path);
        }
    }
    free(cached_text);
    free(path);
    return loaded;
}

static int kv_cache_try_load(server *s, const request *req,
                             ds4_tokens *effective_prompt,
                             char **loaded_path_out,
                             uint8_t *loaded_ext_flags_out) {
    return kv_cache_try_load_text(s, req ? req->prompt_text : NULL,
                                  effective_prompt,
                                  loaded_path_out,
                                  loaded_ext_flags_out,
                                  req && req->api == API_RESPONSES);
}

static int live_text_prefix_prompt(server *s, const request *req,
                                   ds4_tokens *effective_prompt) {
    if (!s || !req || !req->prompt_text || !effective_prompt) return 0;
    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len <= 0) return 0;

    size_t live_text_len = 0;
    char *live_text = render_tokens_text(s->engine, live_tokens, &live_text_len);
    const size_t prompt_text_len = strlen(req->prompt_text);
    if (!byte_prefix_match(req->prompt_text, prompt_text_len,
                           live_text, live_text_len))
    {
        free(live_text);
        return 0;
    }

    /* This is the core text-prefix case.  The live graph is authoritative, so
     * keep its sampled tokenization and tokenize only the request bytes that
     * come after it.  Reusing req->prompt's token suffix would be wrong: full
     * prompt BPE may have merged across this byte boundary. */
    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->prompt_text + live_text_len,
        effective_prompt);
    free(live_text);
    return live_tokens->len;
}

/* Tool-output-only Responses continuation.
 *
 * Some clients send just the new tool outputs after a tool call.  There is no
 * long visible prefix to match in that shape; the call_id itself is the
 * protocol binding to the previous live assistant output.  Use it only when 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
loaded, text_bytes, hdr.quant_bits, key_kind, load_ms, path);
        } else {
            kv_cache_touch_file(path, hdr.hits + 1);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache hit text%s%s tokens=%d text=%u quant=%u key=%s load=%.1f ms file=%s",
                       responses_protocol ? " " : "",
                       responses_protocol ? "RESPPROTO" : "",
                       loaded, text_bytes, hdr.quant_bits, key_kind, load_ms, path);
        }
    }
    free(cached_text);
    free(path);
    return loaded;
}

static int kv_cache_try_load(server *s, const request *req,
                             ds4_tokens *effective_prompt,
                             char **loaded_path_out,
                             uint8_t *loaded_ext_flags_out) {
    return kv_cache_try_load_text(s, req ? req->prompt_text : NULL,
                                  effective_prompt,
                                  loaded_path_out,
                                  loaded_ext_flags_out,
                                  req && req->api == API_RESPONSES);
}

static int live_text_prefix_prompt(server *s, const request *req,
                                   ds4_tokens *effective_prompt) {
    if (!s || !req || !req->prompt_text || !effective_prompt) return 0;
    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len <= 0) return 0;

    size_t live_text_len = 0;
    char *live_text = render_tokens_text(s->engine, live_tokens, &live_text_len);
    const size_t prompt_text_len = strlen(req->prompt_text);
    if (!byte_prefix_match(req->prompt_text, prompt_text_len,
                           live_text, live_text_len))
    {
        free(live_text);
        return 0;
    }

    /* This is the core text-prefix case.  The live graph is authoritative, so
     * keep its sampled tokenization and tokenize only the request bytes that
     * come after it.  Reusing req->prompt's token suffix would be wrong: full
     * prompt BPE may have merged across this byte boundary. */
    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->prompt_text + live_text_len,
        effective_prompt);
    free(live_text);
    return live_tokens->len;
}

/* Tool-output-only Responses continuation.
 *
 * Some clients send just the new tool outputs after a tool call.  There is no
 * long visible prefix to match in that shape; the call_id itself is the
 * protocol binding to the previous live assistant output.  Use it only when 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
loaded, text_bytes, hdr.quant_bits, key_kind, load_ms, path);
        } else {
            kv_cache_touch_file(path, hdr.hits + 1);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache hit text%s%s tokens=%d text=%u quant=%u key=%s load=%.1f ms file=%s",
                       responses_protocol ? " " : "",
                       responses_protocol ? "RESPPROTO" : "",
                       loaded, text_bytes, hdr.quant_bits, key_kind, load_ms, path);
        }
    }
    free(cached_text);
    free(path);
    return loaded;
}

static int kv_cache_try_load(server *s, const request *req,
                             ds4_tokens *effective_prompt,
                             char **loaded_path_out,
                             uint8_t *loaded_ext_flags_out) {
    return kv_cache_try_load_text(s, req ? req->prompt_text : NULL,
                                  effective_prompt,
                                  loaded_path_out,
                                  loaded_ext_flags_out,
                                  req && req->api == API_RESPONSES);
}

static int live_text_prefix_prompt(server *s, const request *req,
                                   ds4_tokens *effective_prompt) {
    if (!s || !req || !req->prompt_text || !effective_prompt) return 0;
    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len <= 0) return 0;

    size_t live_text_len = 0;
    char *live_text = render_tokens_text(s->engine, live_tokens, &live_text_len);
    const size_t prompt_text_len = strlen(req->prompt_text);
    if (!byte_prefix_match(req->prompt_text, prompt_text_len,
                           live_text, live_text_len))
    {
        free(live_text);
        return 0;
    }

    /* This is the core text-prefix case.  The live graph is authoritative, so
     * keep its sampled tokenization and tokenize only the request bytes that
     * come after it.  Reusing req->prompt's token suffix would be wrong: full
     * prompt BPE may have merged across this byte boundary. */
    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->prompt_text + live_text_len,
        effective_prompt);
    free(live_text);
    return live_tokens->len;
}

/* Tool-output-only Responses continuation.
 *
 * Some clients send just the new tool outputs after a tool call.  There is no
 * long visible prefix to match in that shape; the call_id itself is the
 * protocol binding to the previous live assistant output.  Use it only when 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
loaded, text_bytes, hdr.quant_bits, key_kind, load_ms, path);
        } else {
            kv_cache_touch_file(path, hdr.hits + 1);
            server_log(DS4_LOG_KVCACHE,
                       "ds4-server: kv cache hit text%s%s tokens=%d text=%u quant=%u key=%s load=%.1f ms file=%s",
                       responses_protocol ? " " : "",
                       responses_protocol ? "RESPPROTO" : "",
                       loaded, text_bytes, hdr.quant_bits, key_kind, load_ms, path);
        }
    }
    free(cached_text);
    free(path);
    return loaded;
}

static int kv_cache_try_load(server *s, const request *req,
                             ds4_tokens *effective_prompt,
                             char **loaded_path_out,
                             uint8_t *loaded_ext_flags_out) {
    return kv_cache_try_load_text(s, req ? req->prompt_text : NULL,
                                  effective_prompt,
                                  loaded_path_out,
                                  loaded_ext_flags_out,
                                  req && req->api == API_RESPONSES);
}

static int live_text_prefix_prompt(server *s, const request *req,
                                   ds4_tokens *effective_prompt) {
    if (!s || !req || !req->prompt_text || !effective_prompt) return 0;
    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len <= 0) return 0;

    size_t live_text_len = 0;
    char *live_text = render_tokens_text(s->engine, live_tokens, &live_text_len);
    const size_t prompt_text_len = strlen(req->prompt_text);
    if (!byte_prefix_match(req->prompt_text, prompt_text_len,
                           live_text, live_text_len))
    {
        free(live_text);
        return 0;
    }

    /* This is the core text-prefix case.  The live graph is authoritative, so
     * keep its sampled tokenization and tokenize only the request bytes that
     * come after it.  Reusing req->prompt's token suffix would be wrong: full
     * prompt BPE may have merged across this byte boundary. */
    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->prompt_text + live_text_len,
        effective_prompt);
    free(live_text);
    return live_tokens->len;
}

/* Tool-output-only Responses continuation.
 *
 * Some clients send just the new tool outputs after a tool call.  There is no
 * long visible prefix to match in that shape; the call_id itself is the
 * protocol binding to the previous live assistant output.  Use it only when 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
a tool call.  There is no
 * long visible prefix to match in that shape; the call_id itself is the
 * protocol binding to the previous live assistant output.  Use it only when the
 * remembered live frontier and call-id set match exactly. */
static int responses_live_continuation_prompt(server *s, const request *req,
                                              int live_pos,
                                              ds4_tokens *effective_prompt,
                                              int *matched_ids) {
    if (!s || !req || !effective_prompt) return 0;
    if (req->api != API_RESPONSES || !req->responses_live_suffix_text) return 0;
    if (req->responses_live_call_ids.len == 0) return 0;
    if (!responses_live_matches_request(s, &req->responses_live_call_ids,
                                        live_pos)) return 0;

    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len != live_pos) return 0;

    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->responses_live_suffix_text,
        effective_prompt);
    if (matched_ids) *matched_ids = req->responses_live_call_ids.len;
    return live_tokens->len;
}

/* Tool-result Anthropic continuation.
 *
 * /v1/messages has no server-side response object like the OpenAI Responses
 * API, but its tool_use_id is still a precise continuation handle inside a live
 * local agent loop.  When the IDs and live token frontier match, continue from
 * the sampled DSML state and append only the user tool_result suffix. */
static int anthropic_live_continuation_prompt(server *s, const request *req,
                                              int live_pos,
                                              ds4_tokens *effective_prompt,
                                              int *matched_ids) {
    if (!s || !req || !effective_prompt) return 0;
    if (req->api != API_ANTHROPIC || !req->anthropic_live_suffix_text) return 0;
    if (req->anthropic_live_call_ids.len == 0) return 0;
    if (!anthropic_live_matches_request(s, &req->anthropic_live_call_ids,
                                        live_pos)) return 0;

    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len != live_pos) return 0;

    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->anthropic_live_suffix_text,
        effective_prompt);
    if (matched_ids) *matched_ids = req->anthropic_live_call_ids.len;
    return live_tokens->len;
}
```

<｜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
a tool call.  There is no
 * long visible prefix to match in that shape; the call_id itself is the
 * protocol binding to the previous live assistant output.  Use it only when the
 * remembered live frontier and call-id set match exactly. */
static int responses_live_continuation_prompt(server *s, const request *req,
                                              int live_pos,
                                              ds4_tokens *effective_prompt,
                                              int *matched_ids) {
    if (!s || !req || !effective_prompt) return 0;
    if (req->api != API_RESPONSES || !req->responses_live_suffix_text) return 0;
    if (req->responses_live_call_ids.len == 0) return 0;
    if (!responses_live_matches_request(s, &req->responses_live_call_ids,
                                        live_pos)) return 0;

    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len != live_pos) return 0;

    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->responses_live_suffix_text,
        effective_prompt);
    if (matched_ids) *matched_ids = req->responses_live_call_ids.len;
    return live_tokens->len;
}

/* Tool-result Anthropic continuation.
 *
 * /v1/messages has no server-side response object like the OpenAI Responses
 * API, but its tool_use_id is still a precise continuation handle inside a live
 * local agent loop.  When the IDs and live token frontier match, continue from
 * the sampled DSML state and append only the user tool_result suffix. */
static int anthropic_live_continuation_prompt(server *s, const request *req,
                                              int live_pos,
                                              ds4_tokens *effective_prompt,
                                              int *matched_ids) {
    if (!s || !req || !effective_prompt) return 0;
    if (req->api != API_ANTHROPIC || !req->anthropic_live_suffix_text) return 0;
    if (req->anthropic_live_call_ids.len == 0) return 0;
    if (!anthropic_live_matches_request(s, &req->anthropic_live_call_ids,
                                        live_pos)) return 0;

    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len != live_pos) return 0;

    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->anthropic_live_suffix_text,
        effective_prompt);
    if (matched_ids) *matched_ids = req->anthropic_live_call_ids.len;
    return live_tokens->len;
}
```<｜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
a tool call.  There is no
 * long visible prefix to match in that shape; the call_id itself is the
 * protocol binding to the previous live assistant output.  Use it only when the
 * remembered live frontier and call-id set match exactly. */
static int responses_live_continuation_prompt(server *s, const request *req,
                                              int live_pos,
                                              ds4_tokens *effective_prompt,
                                              int *matched_ids) {
    if (!s || !req || !effective_prompt) return 0;
    if (req->api != API_RESPONSES || !req->responses_live_suffix_text) return 0;
    if (req->responses_live_call_ids.len == 0) return 0;
    if (!responses_live_matches_request(s, &req->responses_live_call_ids,
                                        live_pos)) return 0;

    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len != live_pos) return 0;

    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->responses_live_suffix_text,
        effective_prompt);
    if (matched_ids) *matched_ids = req->responses_live_call_ids.len;
    return live_tokens->len;
}

/* Tool-result Anthropic continuation.
 *
 * /v1/messages has no server-side response object like the OpenAI Responses
 * API, but its tool_use_id is still a precise continuation handle inside a live
 * local agent loop.  When the IDs and live token frontier match, continue from
 * the sampled DSML state and append only the user tool_result suffix. */
static int anthropic_live_continuation_prompt(server *s, const request *req,
                                              int live_pos,
                                              ds4_tokens *effective_prompt,
                                              int *matched_ids) {
    if (!s || !req || !effective_prompt) return 0;
    if (req->api != API_ANTHROPIC || !req->anthropic_live_suffix_text) return 0;
    if (req->anthropic_live_call_ids.len == 0) return 0;
    if (!anthropic_live_matches_request(s, &req->anthropic_live_call_ids,
                                        live_pos)) return 0;

    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len != live_pos) return 0;

    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->anthropic_live_suffix_text,
        effective_prompt);
    if (matched_ids) *matched_ids = req->anthropic_live_call_ids.len;
    return live_tokens->len;
}
```

<｜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
a tool call.  There is no
 * long visible prefix to match in that shape; the call_id itself is the
 * protocol binding to the previous live assistant output.  Use it only when the
 * remembered live frontier and call-id set match exactly. */
static int responses_live_continuation_prompt(server *s, const request *req,
                                              int live_pos,
                                              ds4_tokens *effective_prompt,
                                              int *matched_ids) {
    if (!s || !req || !effective_prompt) return 0;
    if (req->api != API_RESPONSES || !req->responses_live_suffix_text) return 0;
    if (req->responses_live_call_ids.len == 0) return 0;
    if (!responses_live_matches_request(s, &req->responses_live_call_ids,
                                        live_pos)) return 0;

    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len != live_pos) return 0;

    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->responses_live_suffix_text,
        effective_prompt);
    if (matched_ids) *matched_ids = req->responses_live_call_ids.len;
    return live_tokens->len;
}

/* Tool-result Anthropic continuation.
 *
 * /v1/messages has no server-side response object like the OpenAI Responses
 * API, but its tool_use_id is still a precise continuation handle inside a live
 * local agent loop.  When the IDs and live token frontier match, continue from
 * the sampled DSML state and append only the user tool_result suffix. */
static int anthropic_live_continuation_prompt(server *s, const request *req,
                                              int live_pos,
                                              ds4_tokens *effective_prompt,
                                              int *matched_ids) {
    if (!s || !req || !effective_prompt) return 0;
    if (req->api != API_ANTHROPIC || !req->anthropic_live_suffix_text) return 0;
    if (req->anthropic_live_call_ids.len == 0) return 0;
    if (!anthropic_live_matches_request(s, &req->anthropic_live_call_ids,
                                        live_pos)) return 0;

    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len != live_pos) return 0;

    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->anthropic_live_suffix_text,
        effective_prompt);
    if (matched_ids) *matched_ids = req->anthropic_live_call_ids.len;
    return live_tokens->len;
}
```<｜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
gine, live_tokens, req->anthropic_live_suffix_text,
        effective_prompt);
    if (matched_ids) *matched_ids = req->anthropic_live_call_ids.len;
    return live_tokens->len;
}

/* Visible-replay Responses continuation.
 *
 * Other clients send the full visible transcript on every turn even though the
 * API semantics still make the request a continuation.  For Responses, exact
 * token-prefix matching is the wrong first question: hidden reasoning may be
 * live in KV but absent from the replay by design.  Instead, verify that the
 * request's rendered text begins with the visible transcript remembered at the
 * live frontier.  If it does, continue from the live token prefix and tokenize
 * only the bytes after that visible boundary.
 *
 * If this check fails, DS4 has no special Responses state to trust.  The caller
 * then uses normal token/text/disk matching, which is the correct fallback for
 * cold starts, edits, restarts, or cross-client replays. */
static int responses_live_visible_prefix_prompt(server *s, const request *req,
                                                int live_pos,
                                                ds4_tokens *effective_prompt) {
    if (!s || !req || !req->prompt_text || !effective_prompt) return 0;
    if (req->api != API_RESPONSES) return 0;

    const size_t prompt_len = strlen(req->prompt_text);
    size_t visible_len = 0;
    pthread_mutex_lock(&s->tool_mu);
    bool ok = s->responses_live.valid &&
              s->responses_live.live_tokens == live_pos &&
              s->responses_live.visible_text &&
              s->responses_live.visible_len < prompt_len &&
              byte_prefix_match(req->prompt_text, prompt_len,
                                s->responses_live.visible_text,
                                s->responses_live.visible_len);
    if (ok) visible_len = s->responses_live.visible_len;
    pthread_mutex_unlock(&s->tool_mu);
    if (!ok) return 0;

    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len != live_pos) return 0;

    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->prompt_text + visible_len,
        effective_prompt);
    return live_tokens->len;
}

/* Tool-less thinking continuation.
 *
 * Chat/completions and Anthropic do not have a previous_response_id object that
 * binds a later request to the last sampled turn.  Still, after a normal
 * tool-less thinking answer, the next prompt renderer intentionally omits that
```

<｜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
gine, live_tokens, req->anthropic_live_suffix_text,
        effective_prompt);
    if (matched_ids) *matched_ids = req->anthropic_live_call_ids.len;
    return live_tokens->len;
}

/* Visible-replay Responses continuation.
 *
 * Other clients send the full visible transcript on every turn even though the
 * API semantics still make the request a continuation.  For Responses, exact
 * token-prefix matching is the wrong first question: hidden reasoning may be
 * live in KV but absent from the replay by design.  Instead, verify that the
 * request's rendered text begins with the visible transcript remembered at the
 * live frontier.  If it does, continue from the live token prefix and tokenize
 * only the bytes after that visible boundary.
 *
 * If this check fails, DS4 has no special Responses state to trust.  The caller
 * then uses normal token/text/disk matching, which is the correct fallback for
 * cold starts, edits, restarts, or cross-client replays. */
static int responses_live_visible_prefix_prompt(server *s, const request *req,
                                                int live_pos,
                                                ds4_tokens *effective_prompt) {
    if (!s || !req || !req->prompt_text || !effective_prompt) return 0;
    if (req->api != API_RESPONSES) return 0;

    const size_t prompt_len = strlen(req->prompt_text);
    size_t visible_len = 0;
    pthread_mutex_lock(&s->tool_mu);
    bool ok = s->responses_live.valid &&
              s->responses_live.live_tokens == live_pos &&
              s->responses_live.visible_text &&
              s->responses_live.visible_len < prompt_len &&
              byte_prefix_match(req->prompt_text, prompt_len,
                                s->responses_live.visible_text,
                                s->responses_live.visible_len);
    if (ok) visible_len = s->responses_live.visible_len;
    pthread_mutex_unlock(&s->tool_mu);
    if (!ok) return 0;

    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len != live_pos) return 0;

    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->prompt_text + visible_len,
        effective_prompt);
    return live_tokens->len;
}

/* Tool-less thinking continuation.
 *
 * Chat/completions and Anthropic do not have a previous_response_id object that
 * binds a later request to the last sampled turn.  Still, after a normal
 * tool-less thinking answer, the next prompt renderer intentionally omits that
```<｜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
gine, live_tokens, req->anthropic_live_suffix_text,
        effective_prompt);
    if (matched_ids) *matched_ids = req->anthropic_live_call_ids.len;
    return live_tokens->len;
}

/* Visible-replay Responses continuation.
 *
 * Other clients send the full visible transcript on every turn even though the
 * API semantics still make the request a continuation.  For Responses, exact
 * token-prefix matching is the wrong first question: hidden reasoning may be
 * live in KV but absent from the replay by design.  Instead, verify that the
 * request's rendered text begins with the visible transcript remembered at the
 * live frontier.  If it does, continue from the live token prefix and tokenize
 * only the bytes after that visible boundary.
 *
 * If this check fails, DS4 has no special Responses state to trust.  The caller
 * then uses normal token/text/disk matching, which is the correct fallback for
 * cold starts, edits, restarts, or cross-client replays. */
static int responses_live_visible_prefix_prompt(server *s, const request *req,
                                                int live_pos,
                                                ds4_tokens *effective_prompt) {
    if (!s || !req || !req->prompt_text || !effective_prompt) return 0;
    if (req->api != API_RESPONSES) return 0;

    const size_t prompt_len = strlen(req->prompt_text);
    size_t visible_len = 0;
    pthread_mutex_lock(&s->tool_mu);
    bool ok = s->responses_live.valid &&
              s->responses_live.live_tokens == live_pos &&
              s->responses_live.visible_text &&
              s->responses_live.visible_len < prompt_len &&
              byte_prefix_match(req->prompt_text, prompt_len,
                                s->responses_live.visible_text,
                                s->responses_live.visible_len);
    if (ok) visible_len = s->responses_live.visible_len;
    pthread_mutex_unlock(&s->tool_mu);
    if (!ok) return 0;

    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len != live_pos) return 0;

    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->prompt_text + visible_len,
        effective_prompt);
    return live_tokens->len;
}

/* Tool-less thinking continuation.
 *
 * Chat/completions and Anthropic do not have a previous_response_id object that
 * binds a later request to the last sampled turn.  Still, after a normal
 * tool-less thinking answer, the next prompt renderer intentionally omits that
```

<｜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
gine, live_tokens, req->anthropic_live_suffix_text,
        effective_prompt);
    if (matched_ids) *matched_ids = req->anthropic_live_call_ids.len;
    return live_tokens->len;
}

/* Visible-replay Responses continuation.
 *
 * Other clients send the full visible transcript on every turn even though the
 * API semantics still make the request a continuation.  For Responses, exact
 * token-prefix matching is the wrong first question: hidden reasoning may be
 * live in KV but absent from the replay by design.  Instead, verify that the
 * request's rendered text begins with the visible transcript remembered at the
 * live frontier.  If it does, continue from the live token prefix and tokenize
 * only the bytes after that visible boundary.
 *
 * If this check fails, DS4 has no special Responses state to trust.  The caller
 * then uses normal token/text/disk matching, which is the correct fallback for
 * cold starts, edits, restarts, or cross-client replays. */
static int responses_live_visible_prefix_prompt(server *s, const request *req,
                                                int live_pos,
                                                ds4_tokens *effective_prompt) {
    if (!s || !req || !req->prompt_text || !effective_prompt) return 0;
    if (req->api != API_RESPONSES) return 0;

    const size_t prompt_len = strlen(req->prompt_text);
    size_t visible_len = 0;
    pthread_mutex_lock(&s->tool_mu);
    bool ok = s->responses_live.valid &&
              s->responses_live.live_tokens == live_pos &&
              s->responses_live.visible_text &&
              s->responses_live.visible_len < prompt_len &&
              byte_prefix_match(req->prompt_text, prompt_len,
                                s->responses_live.visible_text,
                                s->responses_live.visible_len);
    if (ok) visible_len = s->responses_live.visible_len;
    pthread_mutex_unlock(&s->tool_mu);
    if (!ok) return 0;

    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len != live_pos) return 0;

    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->prompt_text + visible_len,
        effective_prompt);
    return live_tokens->len;
}

/* Tool-less thinking continuation.
 *
 * Chat/completions and Anthropic do not have a previous_response_id object that
 * binds a later request to the last sampled turn.  Still, after a normal
 * tool-less thinking answer, the next prompt renderer intentionally omits that
```<｜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
us_response_id object that
 * binds a later request to the last sampled turn.  Still, after a normal
 * tool-less thinking answer, the next prompt renderer intentionally omits that
 * hidden reasoning.  The live KV state is richer than the visible transcript.
 *
 * Remembering the visible transcript as a key lets us keep the sampled hidden
 * KV when the next request clearly extends that same visible history.  This is
 * the same byte-prefix idea used by the disk cache: the client-visible text
 * selects the checkpoint, while the payload stays the exact sampled token
 * frontier.  If the visible key does not match, callers fall back to ordinary
 * token/text/disk matching. */
static int thinking_live_visible_prefix_prompt(server *s, const request *req,
                                               int live_pos,
                                               ds4_tokens *effective_prompt) {
    if (!s || !req || !req->prompt_text || !effective_prompt) return 0;
    if (req->kind != REQ_CHAT || req->api == API_RESPONSES) return 0;

    const size_t prompt_len = strlen(req->prompt_text);
    size_t visible_len = 0;
    pthread_mutex_lock(&s->tool_mu);
    bool ok = s->thinking_live.valid &&
              s->thinking_live.live_tokens == live_pos &&
              s->thinking_live.visible_text &&
              s->thinking_live.visible_len < prompt_len &&
              byte_prefix_match(req->prompt_text, prompt_len,
                                s->thinking_live.visible_text,
                                s->thinking_live.visible_len);
    if (ok) visible_len = s->thinking_live.visible_len;
    pthread_mutex_unlock(&s->tool_mu);
    if (!ok) return 0;

    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len != live_pos) return 0;

    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->prompt_text + visible_len,
        effective_prompt);
    return live_tokens->len;
}

/* =========================================================================
 * Trace Diagnostics.
 * =========================================================================
 *
 * The human transcript is not enough to debug prompt-cache misses.  The model
 * may generate text that is semantically accepted as a tool call, while the
 * next OpenAI request re-renders a slightly different canonical DSML block.
 * That creates a token mismatch even if the conversation "looks" continuous.
 *
 * When --trace is enabled we therefore record the exact cache decision and a
```

<｜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
us_response_id object that
 * binds a later request to the last sampled turn.  Still, after a normal
 * tool-less thinking answer, the next prompt renderer intentionally omits that
 * hidden reasoning.  The live KV state is richer than the visible transcript.
 *
 * Remembering the visible transcript as a key lets us keep the sampled hidden
 * KV when the next request clearly extends that same visible history.  This is
 * the same byte-prefix idea used by the disk cache: the client-visible text
 * selects the checkpoint, while the payload stays the exact sampled token
 * frontier.  If the visible key does not match, callers fall back to ordinary
 * token/text/disk matching. */
static int thinking_live_visible_prefix_prompt(server *s, const request *req,
                                               int live_pos,
                                               ds4_tokens *effective_prompt) {
    if (!s || !req || !req->prompt_text || !effective_prompt) return 0;
    if (req->kind != REQ_CHAT || req->api == API_RESPONSES) return 0;

    const size_t prompt_len = strlen(req->prompt_text);
    size_t visible_len = 0;
    pthread_mutex_lock(&s->tool_mu);
    bool ok = s->thinking_live.valid &&
              s->thinking_live.live_tokens == live_pos &&
              s->thinking_live.visible_text &&
              s->thinking_live.visible_len < prompt_len &&
              byte_prefix_match(req->prompt_text, prompt_len,
                                s->thinking_live.visible_text,
                                s->thinking_live.visible_len);
    if (ok) visible_len = s->thinking_live.visible_len;
    pthread_mutex_unlock(&s->tool_mu);
    if (!ok) return 0;

    const ds4_tokens *live_tokens = ds4_session_tokens(s->session);
    if (!live_tokens || live_tokens->len != live_pos) return 0;

    build_prompt_from_exact_prefix_and_text_suffix(
        s->engine, live_tokens, req->prompt_text + visible_len,
        effective_prompt);
    return live_tokens->len;
}

/* =========================================================================
 * Trace Diagnostics.
 * =========================================================================
 *
 * The human transcript is not enough to debug prompt-cache misses.  The model
 * may generate text that is semantically accepted as a tool call, while the
 * next OpenAI request re-renders a slightly different canonical DSML block.
 * That creates a token mismatch even if the conversation "looks" continuous.
 *
 * When --trace is enabled we therefore record the exact cache decision and a
```<｜Assistant｜></think>