[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_cli.c

```c
prompt->len, cfg->gen.ctx_size, k);
    int generated = 0;
    int max_tokens = cfg->gen.n_predict;
    int room = ds4_session_ctx(session) - ds4_session_pos(session);
    if (room <= 1) max_tokens = 0;
    else if (max_tokens > room - 1) max_tokens = room - 1;
    for (; generated < max_tokens; generated++) {
        int n = ds4_session_top_logprobs(session, scores, k);
        int token = ds4_session_argmax(session);
        if (generated) fputs(",\n", fp);
        fprintf(fp, "    {\"step\":%d,\"selected\":", generated);
        json_write_token(fp, engine, token);
        fputs(",\"top_logprobs\":[", fp);
        for (int i = 0; i < n && scores[i].id >= 0; i++) {
            if (i) fputc(',', fp);
            fputs("{\"token\":", fp);
            json_write_token(fp, engine, scores[i].id);
            fprintf(fp, ",\"logit\":%.9g,\"logprob\":%.9g}", scores[i].logit, scores[i].logprob);
        }
        fputs("]}", fp);

        if (token == ds4_token_eos(engine)) break;
        if (ds4_session_eval(session, token, err, sizeof(err)) != 0) {
            fprintf(stderr, "ds4: decode failed while dumping logprobs: %s\n", err);
            free(scores);
            fclose(fp);
            ds4_session_free(session);
            return 1;
        }
    }
    fputs("\n  ]\n}\n", fp);
    if (fclose(fp) != 0) {
        fprintf(stderr, "ds4: failed to close --dump-logprobs file: %s\n", cfg->gen.dump_logprobs_path);
        free(scores);
        ds4_session_free(session);
        return 1;
    }
    free(scores);
    ds4_session_free(session);
    return 0;
}

static int run_generation(ds4_engine *engine, const cli_config *cfg) {
    ds4_tokens prompt = {0};
    build_prompt(engine, &cfg->gen, &prompt);

    int rc = 0;
    if (cfg->gen.metal_graph_test) {
        rc = ds4_engine_metal_graph_test(engine, &prompt);
        ds4_tokens_free(&prompt);
        return rc;
    }
    if (cfg->gen.metal_graph_full_test) {
        rc = ds4_engine_metal_graph_full_test(engine, &prompt);
        ds4_tokens_free(&prompt);
        return rc;
    }
    if (cfg->gen.metal_graph_prompt_test) {
        rc = ds4_engine_metal_graph_prompt_test(engine, &prompt, cfg->gen.ctx_size);
        ds4_tokens_free(&prompt);
        return rc;
    }
    if (cfg->gen.dump_logprobs_path) {
        rc = run_logprob_dump(engine, cfg, &prompt);
        ds4_tokens_free(&prompt);
        return rc;
    }

    const bool diagnostic = cfg->gen.dump_tokens ||
                            cfg->gen.head_test ||
                            cfg->gen.first_token_test;
```

<｜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_cli.c

```c
prompt->len, cfg->gen.ctx_size, k);
    int generated = 0;
    int max_tokens = cfg->gen.n_predict;
    int room = ds4_session_ctx(session) - ds4_session_pos(session);
    if (room <= 1) max_tokens = 0;
    else if (max_tokens > room - 1) max_tokens = room - 1;
    for (; generated < max_tokens; generated++) {
        int n = ds4_session_top_logprobs(session, scores, k);
        int token = ds4_session_argmax(session);
        if (generated) fputs(",\n", fp);
        fprintf(fp, "    {\"step\":%d,\"selected\":", generated);
        json_write_token(fp, engine, token);
        fputs(",\"top_logprobs\":[", fp);
        for (int i = 0; i < n && scores[i].id >= 0; i++) {
            if (i) fputc(',', fp);
            fputs("{\"token\":", fp);
            json_write_token(fp, engine, scores[i].id);
            fprintf(fp, ",\"logit\":%.9g,\"logprob\":%.9g}", scores[i].logit, scores[i].logprob);
        }
        fputs("]}", fp);

        if (token == ds4_token_eos(engine)) break;
        if (ds4_session_eval(session, token, err, sizeof(err)) != 0) {
            fprintf(stderr, "ds4: decode failed while dumping logprobs: %s\n", err);
            free(scores);
            fclose(fp);
            ds4_session_free(session);
            return 1;
        }
    }
    fputs("\n  ]\n}\n", fp);
    if (fclose(fp) != 0) {
        fprintf(stderr, "ds4: failed to close --dump-logprobs file: %s\n", cfg->gen.dump_logprobs_path);
        free(scores);
        ds4_session_free(session);
        return 1;
    }
    free(scores);
    ds4_session_free(session);
    return 0;
}

static int run_generation(ds4_engine *engine, const cli_config *cfg) {
    ds4_tokens prompt = {0};
    build_prompt(engine, &cfg->gen, &prompt);

    int rc = 0;
    if (cfg->gen.metal_graph_test) {
        rc = ds4_engine_metal_graph_test(engine, &prompt);
        ds4_tokens_free(&prompt);
        return rc;
    }
    if (cfg->gen.metal_graph_full_test) {
        rc = ds4_engine_metal_graph_full_test(engine, &prompt);
        ds4_tokens_free(&prompt);
        return rc;
    }
    if (cfg->gen.metal_graph_prompt_test) {
        rc = ds4_engine_metal_graph_prompt_test(engine, &prompt, cfg->gen.ctx_size);
        ds4_tokens_free(&prompt);
        return rc;
    }
    if (cfg->gen.dump_logprobs_path) {
        rc = run_logprob_dump(engine, cfg, &prompt);
        ds4_tokens_free(&prompt);
        return rc;
    }

    const bool diagnostic = cfg->gen.dump_tokens ||
                            cfg->gen.head_test ||
                            cfg->gen.first_token_test;
```<｜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_cli.c

```c
prompt->len, cfg->gen.ctx_size, k);
    int generated = 0;
    int max_tokens = cfg->gen.n_predict;
    int room = ds4_session_ctx(session) - ds4_session_pos(session);
    if (room <= 1) max_tokens = 0;
    else if (max_tokens > room - 1) max_tokens = room - 1;
    for (; generated < max_tokens; generated++) {
        int n = ds4_session_top_logprobs(session, scores, k);
        int token = ds4_session_argmax(session);
        if (generated) fputs(",\n", fp);
        fprintf(fp, "    {\"step\":%d,\"selected\":", generated);
        json_write_token(fp, engine, token);
        fputs(",\"top_logprobs\":[", fp);
        for (int i = 0; i < n && scores[i].id >= 0; i++) {
            if (i) fputc(',', fp);
            fputs("{\"token\":", fp);
            json_write_token(fp, engine, scores[i].id);
            fprintf(fp, ",\"logit\":%.9g,\"logprob\":%.9g}", scores[i].logit, scores[i].logprob);
        }
        fputs("]}", fp);

        if (token == ds4_token_eos(engine)) break;
        if (ds4_session_eval(session, token, err, sizeof(err)) != 0) {
            fprintf(stderr, "ds4: decode failed while dumping logprobs: %s\n", err);
            free(scores);
            fclose(fp);
            ds4_session_free(session);
            return 1;
        }
    }
    fputs("\n  ]\n}\n", fp);
    if (fclose(fp) != 0) {
        fprintf(stderr, "ds4: failed to close --dump-logprobs file: %s\n", cfg->gen.dump_logprobs_path);
        free(scores);
        ds4_session_free(session);
        return 1;
    }
    free(scores);
    ds4_session_free(session);
    return 0;
}

static int run_generation(ds4_engine *engine, const cli_config *cfg) {
    ds4_tokens prompt = {0};
    build_prompt(engine, &cfg->gen, &prompt);

    int rc = 0;
    if (cfg->gen.metal_graph_test) {
        rc = ds4_engine_metal_graph_test(engine, &prompt);
        ds4_tokens_free(&prompt);
        return rc;
    }
    if (cfg->gen.metal_graph_full_test) {
        rc = ds4_engine_metal_graph_full_test(engine, &prompt);
        ds4_tokens_free(&prompt);
        return rc;
    }
    if (cfg->gen.metal_graph_prompt_test) {
        rc = ds4_engine_metal_graph_prompt_test(engine, &prompt, cfg->gen.ctx_size);
        ds4_tokens_free(&prompt);
        return rc;
    }
    if (cfg->gen.dump_logprobs_path) {
        rc = run_logprob_dump(engine, cfg, &prompt);
        ds4_tokens_free(&prompt);
        return rc;
    }

    const bool diagnostic = cfg->gen.dump_tokens ||
                            cfg->gen.head_test ||
                            cfg->gen.first_token_test;
```

<｜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_cli.c

```c
prompt->len, cfg->gen.ctx_size, k);
    int generated = 0;
    int max_tokens = cfg->gen.n_predict;
    int room = ds4_session_ctx(session) - ds4_session_pos(session);
    if (room <= 1) max_tokens = 0;
    else if (max_tokens > room - 1) max_tokens = room - 1;
    for (; generated < max_tokens; generated++) {
        int n = ds4_session_top_logprobs(session, scores, k);
        int token = ds4_session_argmax(session);
        if (generated) fputs(",\n", fp);
        fprintf(fp, "    {\"step\":%d,\"selected\":", generated);
        json_write_token(fp, engine, token);
        fputs(",\"top_logprobs\":[", fp);
        for (int i = 0; i < n && scores[i].id >= 0; i++) {
            if (i) fputc(',', fp);
            fputs("{\"token\":", fp);
            json_write_token(fp, engine, scores[i].id);
            fprintf(fp, ",\"logit\":%.9g,\"logprob\":%.9g}", scores[i].logit, scores[i].logprob);
        }
        fputs("]}", fp);

        if (token == ds4_token_eos(engine)) break;
        if (ds4_session_eval(session, token, err, sizeof(err)) != 0) {
            fprintf(stderr, "ds4: decode failed while dumping logprobs: %s\n", err);
            free(scores);
            fclose(fp);
            ds4_session_free(session);
            return 1;
        }
    }
    fputs("\n  ]\n}\n", fp);
    if (fclose(fp) != 0) {
        fprintf(stderr, "ds4: failed to close --dump-logprobs file: %s\n", cfg->gen.dump_logprobs_path);
        free(scores);
        ds4_session_free(session);
        return 1;
    }
    free(scores);
    ds4_session_free(session);
    return 0;
}

static int run_generation(ds4_engine *engine, const cli_config *cfg) {
    ds4_tokens prompt = {0};
    build_prompt(engine, &cfg->gen, &prompt);

    int rc = 0;
    if (cfg->gen.metal_graph_test) {
        rc = ds4_engine_metal_graph_test(engine, &prompt);
        ds4_tokens_free(&prompt);
        return rc;
    }
    if (cfg->gen.metal_graph_full_test) {
        rc = ds4_engine_metal_graph_full_test(engine, &prompt);
        ds4_tokens_free(&prompt);
        return rc;
    }
    if (cfg->gen.metal_graph_prompt_test) {
        rc = ds4_engine_metal_graph_prompt_test(engine, &prompt, cfg->gen.ctx_size);
        ds4_tokens_free(&prompt);
        return rc;
    }
    if (cfg->gen.dump_logprobs_path) {
        rc = run_logprob_dump(engine, cfg, &prompt);
        ds4_tokens_free(&prompt);
        return rc;
    }

    const bool diagnostic = cfg->gen.dump_tokens ||
                            cfg->gen.head_test ||
                            cfg->gen.first_token_test;
```<｜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_cli.c

```c
return rc;
    }

    const bool diagnostic = cfg->gen.dump_tokens ||
                            cfg->gen.head_test ||
                            cfg->gen.first_token_test;
    if (cfg->gen.head_test) {
        rc = ds4_engine_head_test(engine, &prompt);
    }
    if (rc == 0 && cfg->gen.first_token_test) {
        rc = ds4_engine_first_token_test(engine, &prompt);
    }
    if (cfg->gen.dump_tokens) {
        ds4_engine_dump_tokens(engine, &prompt);
    }

    if (diagnostic) {
        if (rc == 0) {
            fprintf(stderr, "ds4: diagnostic run completed on the native %s path.\n",
                    ds4_backend_name(cfg->engine.backend));
        }
    } else if (cfg->gen.temperature > 0.0f || ds4_engine_mtp_draft_tokens(engine) > 1) {
        rc = run_sampled_generation(engine, cfg, &prompt);
    } else {
        token_printer printer = {
            .engine = engine,
            .fp = stdout,
            .format_thinking = ds4_think_mode_enabled(cli_effective_think_mode(&cfg->gen)),
            .in_think = ds4_think_mode_enabled(cli_effective_think_mode(&cfg->gen)),
            .use_color = isatty(fileno(stdout)) != 0,
            .last_output_newline = true,
        };
        cli_prefill_progress progress = {
            .base_tokens = 0,
            .input_tokens = prompt.len,
            .use_color = ds4_log_is_tty(stderr),
        };
        rc = ds4_engine_generate_argmax(engine, &prompt, cfg->gen.n_predict,
                                        cfg->gen.ctx_size,
                                        print_generated_token,
                                        generation_done,
                                        &printer,
                                        cli_prefill_progress_cb,
                                        &progress);
    }

    ds4_tokens_free(&prompt);
    return rc;
}

static char *trim_inplace(char *s) {
    while (*s && isspace((unsigned char)*s)) s++;
    char *end = s + strlen(s);
    while (end > s && isspace((unsigned char)end[-1])) end--;
    *end = '\0';
    return s;
}

static void print_repl_help(void) {
    puts("Commands:");
    puts("  /help          Show this help.");
    puts("  /think         Use normal thinking mode.");
    puts("  /think-max     Use Think Max only when context is at least 393216 tokens.");
    puts("  /nothink       Disable thinking mode.");
    puts("  /ctx N         Set context size for following prompts.");
    puts("  /read FILE     Read a prompt from FILE and run it.");
    puts("  /quit, /exit   Leave the prompt.");
```

<｜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_cli.c

```c
return rc;
    }

    const bool diagnostic = cfg->gen.dump_tokens ||
                            cfg->gen.head_test ||
                            cfg->gen.first_token_test;
    if (cfg->gen.head_test) {
        rc = ds4_engine_head_test(engine, &prompt);
    }
    if (rc == 0 && cfg->gen.first_token_test) {
        rc = ds4_engine_first_token_test(engine, &prompt);
    }
    if (cfg->gen.dump_tokens) {
        ds4_engine_dump_tokens(engine, &prompt);
    }

    if (diagnostic) {
        if (rc == 0) {
            fprintf(stderr, "ds4: diagnostic run completed on the native %s path.\n",
                    ds4_backend_name(cfg->engine.backend));
        }
    } else if (cfg->gen.temperature > 0.0f || ds4_engine_mtp_draft_tokens(engine) > 1) {
        rc = run_sampled_generation(engine, cfg, &prompt);
    } else {
        token_printer printer = {
            .engine = engine,
            .fp = stdout,
            .format_thinking = ds4_think_mode_enabled(cli_effective_think_mode(&cfg->gen)),
            .in_think = ds4_think_mode_enabled(cli_effective_think_mode(&cfg->gen)),
            .use_color = isatty(fileno(stdout)) != 0,
            .last_output_newline = true,
        };
        cli_prefill_progress progress = {
            .base_tokens = 0,
            .input_tokens = prompt.len,
            .use_color = ds4_log_is_tty(stderr),
        };
        rc = ds4_engine_generate_argmax(engine, &prompt, cfg->gen.n_predict,
                                        cfg->gen.ctx_size,
                                        print_generated_token,
                                        generation_done,
                                        &printer,
                                        cli_prefill_progress_cb,
                                        &progress);
    }

    ds4_tokens_free(&prompt);
    return rc;
}

static char *trim_inplace(char *s) {
    while (*s && isspace((unsigned char)*s)) s++;
    char *end = s + strlen(s);
    while (end > s && isspace((unsigned char)end[-1])) end--;
    *end = '\0';
    return s;
}

static void print_repl_help(void) {
    puts("Commands:");
    puts("  /help          Show this help.");
    puts("  /think         Use normal thinking mode.");
    puts("  /think-max     Use Think Max only when context is at least 393216 tokens.");
    puts("  /nothink       Disable thinking mode.");
    puts("  /ctx N         Set context size for following prompts.");
    puts("  /read FILE     Read a prompt from FILE and run it.");
    puts("  /quit, /exit   Leave the prompt.");
```<｜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_cli.c

```c
return rc;
    }

    const bool diagnostic = cfg->gen.dump_tokens ||
                            cfg->gen.head_test ||
                            cfg->gen.first_token_test;
    if (cfg->gen.head_test) {
        rc = ds4_engine_head_test(engine, &prompt);
    }
    if (rc == 0 && cfg->gen.first_token_test) {
        rc = ds4_engine_first_token_test(engine, &prompt);
    }
    if (cfg->gen.dump_tokens) {
        ds4_engine_dump_tokens(engine, &prompt);
    }

    if (diagnostic) {
        if (rc == 0) {
            fprintf(stderr, "ds4: diagnostic run completed on the native %s path.\n",
                    ds4_backend_name(cfg->engine.backend));
        }
    } else if (cfg->gen.temperature > 0.0f || ds4_engine_mtp_draft_tokens(engine) > 1) {
        rc = run_sampled_generation(engine, cfg, &prompt);
    } else {
        token_printer printer = {
            .engine = engine,
            .fp = stdout,
            .format_thinking = ds4_think_mode_enabled(cli_effective_think_mode(&cfg->gen)),
            .in_think = ds4_think_mode_enabled(cli_effective_think_mode(&cfg->gen)),
            .use_color = isatty(fileno(stdout)) != 0,
            .last_output_newline = true,
        };
        cli_prefill_progress progress = {
            .base_tokens = 0,
            .input_tokens = prompt.len,
            .use_color = ds4_log_is_tty(stderr),
        };
        rc = ds4_engine_generate_argmax(engine, &prompt, cfg->gen.n_predict,
                                        cfg->gen.ctx_size,
                                        print_generated_token,
                                        generation_done,
                                        &printer,
                                        cli_prefill_progress_cb,
                                        &progress);
    }

    ds4_tokens_free(&prompt);
    return rc;
}

static char *trim_inplace(char *s) {
    while (*s && isspace((unsigned char)*s)) s++;
    char *end = s + strlen(s);
    while (end > s && isspace((unsigned char)end[-1])) end--;
    *end = '\0';
    return s;
}

static void print_repl_help(void) {
    puts("Commands:");
    puts("  /help          Show this help.");
    puts("  /think         Use normal thinking mode.");
    puts("  /think-max     Use Think Max only when context is at least 393216 tokens.");
    puts("  /nothink       Disable thinking mode.");
    puts("  /ctx N         Set context size for following prompts.");
    puts("  /read FILE     Read a prompt from FILE and run it.");
    puts("  /quit, /exit   Leave the prompt.");
```

<｜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_cli.c

```c
return rc;
    }

    const bool diagnostic = cfg->gen.dump_tokens ||
                            cfg->gen.head_test ||
                            cfg->gen.first_token_test;
    if (cfg->gen.head_test) {
        rc = ds4_engine_head_test(engine, &prompt);
    }
    if (rc == 0 && cfg->gen.first_token_test) {
        rc = ds4_engine_first_token_test(engine, &prompt);
    }
    if (cfg->gen.dump_tokens) {
        ds4_engine_dump_tokens(engine, &prompt);
    }

    if (diagnostic) {
        if (rc == 0) {
            fprintf(stderr, "ds4: diagnostic run completed on the native %s path.\n",
                    ds4_backend_name(cfg->engine.backend));
        }
    } else if (cfg->gen.temperature > 0.0f || ds4_engine_mtp_draft_tokens(engine) > 1) {
        rc = run_sampled_generation(engine, cfg, &prompt);
    } else {
        token_printer printer = {
            .engine = engine,
            .fp = stdout,
            .format_thinking = ds4_think_mode_enabled(cli_effective_think_mode(&cfg->gen)),
            .in_think = ds4_think_mode_enabled(cli_effective_think_mode(&cfg->gen)),
            .use_color = isatty(fileno(stdout)) != 0,
            .last_output_newline = true,
        };
        cli_prefill_progress progress = {
            .base_tokens = 0,
            .input_tokens = prompt.len,
            .use_color = ds4_log_is_tty(stderr),
        };
        rc = ds4_engine_generate_argmax(engine, &prompt, cfg->gen.n_predict,
                                        cfg->gen.ctx_size,
                                        print_generated_token,
                                        generation_done,
                                        &printer,
                                        cli_prefill_progress_cb,
                                        &progress);
    }

    ds4_tokens_free(&prompt);
    return rc;
}

static char *trim_inplace(char *s) {
    while (*s && isspace((unsigned char)*s)) s++;
    char *end = s + strlen(s);
    while (end > s && isspace((unsigned char)end[-1])) end--;
    *end = '\0';
    return s;
}

static void print_repl_help(void) {
    puts("Commands:");
    puts("  /help          Show this help.");
    puts("  /think         Use normal thinking mode.");
    puts("  /think-max     Use Think Max only when context is at least 393216 tokens.");
    puts("  /nothink       Disable thinking mode.");
    puts("  /ctx N         Set context size for following prompts.");
    puts("  /read FILE     Read a prompt from FILE and run it.");
    puts("  /quit, /exit   Leave the prompt.");
```<｜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_cli.c

```c
puts("  /ctx N         Set context size for following prompts.");
    puts("  /read FILE     Read a prompt from FILE and run it.");
    puts("  /quit, /exit   Leave the prompt.");
    puts("  Ctrl+C         Stop generation and return to the prompt.");
}

static void history_file_path(char *buf, size_t len) {
    const char *home = getenv("HOME");
    if (!home || !home[0]) home = ".";
    snprintf(buf, len, "%s/.ds4_history", home);
}

typedef struct {
    ds4_session *session;
    ds4_tokens transcript;
    int ctx_size;
    int max_prefix_tokens;
} repl_chat;

static void tokens_insert(ds4_tokens *dst, int pos, const ds4_tokens *src) {
    if (!src || src->len <= 0) return;
    if (pos < 0) pos = 0;
    if (pos > dst->len) pos = dst->len;
    while (dst->len + src->len > dst->cap) {
        dst->cap = dst->cap ? dst->cap * 2 : 64;
        int *next = realloc(dst->v, (size_t)dst->cap * sizeof(dst->v[0]));
        if (!next) {
            perror("ds4: realloc");
            exit(1);
        }
        dst->v = next;
    }
    memmove(dst->v + pos + src->len, dst->v + pos,
            (size_t)(dst->len - pos) * sizeof(dst->v[0]));
    memcpy(dst->v + pos, src->v, (size_t)src->len * sizeof(src->v[0]));
    dst->len += src->len;
}

static void tokens_remove(ds4_tokens *dst, int pos, int n) {
    if (n <= 0 || pos < 0 || pos >= dst->len) return;
    if (pos + n > dst->len) n = dst->len - pos;
    memmove(dst->v + pos, dst->v + pos + n,
            (size_t)(dst->len - pos - n) * sizeof(dst->v[0]));
    dst->len -= n;
}

/* Insert/remove the Think Max prefix inside the existing transcript.  The
 * prefix lives after BOS, before any system/developer text, which mirrors the
 * API rendering path.  Changing it invalidates the session because every later
 * token position would otherwise refer to the wrong prefix. */
static void repl_chat_apply_max_prefix(ds4_engine *engine, repl_chat *chat, bool enable) {
    if (enable && chat->max_prefix_tokens == 0) {
        ds4_tokens prefix = {0};
        ds4_chat_append_max_effort_prefix(engine, &prefix);
        tokens_insert(&chat->transcript, 1, &prefix);
        chat->max_prefix_tokens = prefix.len;
        ds4_tokens_free(&prefix);
        if (chat->session) ds4_session_invalidate(chat->session);
    } else if (!enable && chat->max_prefix_tokens > 0) {
        tokens_remove(&chat->transcript, 1, chat->max_prefix_tokens);
        chat->max_prefix_tokens = 0;
        if (chat->session) ds4_session_invalidate(chat->session);
    }
}
```

<｜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_cli.c

```c
puts("  /ctx N         Set context size for following prompts.");
    puts("  /read FILE     Read a prompt from FILE and run it.");
    puts("  /quit, /exit   Leave the prompt.");
    puts("  Ctrl+C         Stop generation and return to the prompt.");
}

static void history_file_path(char *buf, size_t len) {
    const char *home = getenv("HOME");
    if (!home || !home[0]) home = ".";
    snprintf(buf, len, "%s/.ds4_history", home);
}

typedef struct {
    ds4_session *session;
    ds4_tokens transcript;
    int ctx_size;
    int max_prefix_tokens;
} repl_chat;

static void tokens_insert(ds4_tokens *dst, int pos, const ds4_tokens *src) {
    if (!src || src->len <= 0) return;
    if (pos < 0) pos = 0;
    if (pos > dst->len) pos = dst->len;
    while (dst->len + src->len > dst->cap) {
        dst->cap = dst->cap ? dst->cap * 2 : 64;
        int *next = realloc(dst->v, (size_t)dst->cap * sizeof(dst->v[0]));
        if (!next) {
            perror("ds4: realloc");
            exit(1);
        }
        dst->v = next;
    }
    memmove(dst->v + pos + src->len, dst->v + pos,
            (size_t)(dst->len - pos) * sizeof(dst->v[0]));
    memcpy(dst->v + pos, src->v, (size_t)src->len * sizeof(src->v[0]));
    dst->len += src->len;
}

static void tokens_remove(ds4_tokens *dst, int pos, int n) {
    if (n <= 0 || pos < 0 || pos >= dst->len) return;
    if (pos + n > dst->len) n = dst->len - pos;
    memmove(dst->v + pos, dst->v + pos + n,
            (size_t)(dst->len - pos - n) * sizeof(dst->v[0]));
    dst->len -= n;
}

/* Insert/remove the Think Max prefix inside the existing transcript.  The
 * prefix lives after BOS, before any system/developer text, which mirrors the
 * API rendering path.  Changing it invalidates the session because every later
 * token position would otherwise refer to the wrong prefix. */
static void repl_chat_apply_max_prefix(ds4_engine *engine, repl_chat *chat, bool enable) {
    if (enable && chat->max_prefix_tokens == 0) {
        ds4_tokens prefix = {0};
        ds4_chat_append_max_effort_prefix(engine, &prefix);
        tokens_insert(&chat->transcript, 1, &prefix);
        chat->max_prefix_tokens = prefix.len;
        ds4_tokens_free(&prefix);
        if (chat->session) ds4_session_invalidate(chat->session);
    } else if (!enable && chat->max_prefix_tokens > 0) {
        tokens_remove(&chat->transcript, 1, chat->max_prefix_tokens);
        chat->max_prefix_tokens = 0;
        if (chat->session) ds4_session_invalidate(chat->session);
    }
}
```<｜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_cli.c

```c
puts("  /ctx N         Set context size for following prompts.");
    puts("  /read FILE     Read a prompt from FILE and run it.");
    puts("  /quit, /exit   Leave the prompt.");
    puts("  Ctrl+C         Stop generation and return to the prompt.");
}

static void history_file_path(char *buf, size_t len) {
    const char *home = getenv("HOME");
    if (!home || !home[0]) home = ".";
    snprintf(buf, len, "%s/.ds4_history", home);
}

typedef struct {
    ds4_session *session;
    ds4_tokens transcript;
    int ctx_size;
    int max_prefix_tokens;
} repl_chat;

static void tokens_insert(ds4_tokens *dst, int pos, const ds4_tokens *src) {
    if (!src || src->len <= 0) return;
    if (pos < 0) pos = 0;
    if (pos > dst->len) pos = dst->len;
    while (dst->len + src->len > dst->cap) {
        dst->cap = dst->cap ? dst->cap * 2 : 64;
        int *next = realloc(dst->v, (size_t)dst->cap * sizeof(dst->v[0]));
        if (!next) {
            perror("ds4: realloc");
            exit(1);
        }
        dst->v = next;
    }
    memmove(dst->v + pos + src->len, dst->v + pos,
            (size_t)(dst->len - pos) * sizeof(dst->v[0]));
    memcpy(dst->v + pos, src->v, (size_t)src->len * sizeof(src->v[0]));
    dst->len += src->len;
}

static void tokens_remove(ds4_tokens *dst, int pos, int n) {
    if (n <= 0 || pos < 0 || pos >= dst->len) return;
    if (pos + n > dst->len) n = dst->len - pos;
    memmove(dst->v + pos, dst->v + pos + n,
            (size_t)(dst->len - pos - n) * sizeof(dst->v[0]));
    dst->len -= n;
}

/* Insert/remove the Think Max prefix inside the existing transcript.  The
 * prefix lives after BOS, before any system/developer text, which mirrors the
 * API rendering path.  Changing it invalidates the session because every later
 * token position would otherwise refer to the wrong prefix. */
static void repl_chat_apply_max_prefix(ds4_engine *engine, repl_chat *chat, bool enable) {
    if (enable && chat->max_prefix_tokens == 0) {
        ds4_tokens prefix = {0};
        ds4_chat_append_max_effort_prefix(engine, &prefix);
        tokens_insert(&chat->transcript, 1, &prefix);
        chat->max_prefix_tokens = prefix.len;
        ds4_tokens_free(&prefix);
        if (chat->session) ds4_session_invalidate(chat->session);
    } else if (!enable && chat->max_prefix_tokens > 0) {
        tokens_remove(&chat->transcript, 1, chat->max_prefix_tokens);
        chat->max_prefix_tokens = 0;
        if (chat->session) ds4_session_invalidate(chat->session);
    }
}
```

<｜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_cli.c

```c
puts("  /ctx N         Set context size for following prompts.");
    puts("  /read FILE     Read a prompt from FILE and run it.");
    puts("  /quit, /exit   Leave the prompt.");
    puts("  Ctrl+C         Stop generation and return to the prompt.");
}

static void history_file_path(char *buf, size_t len) {
    const char *home = getenv("HOME");
    if (!home || !home[0]) home = ".";
    snprintf(buf, len, "%s/.ds4_history", home);
}

typedef struct {
    ds4_session *session;
    ds4_tokens transcript;
    int ctx_size;
    int max_prefix_tokens;
} repl_chat;

static void tokens_insert(ds4_tokens *dst, int pos, const ds4_tokens *src) {
    if (!src || src->len <= 0) return;
    if (pos < 0) pos = 0;
    if (pos > dst->len) pos = dst->len;
    while (dst->len + src->len > dst->cap) {
        dst->cap = dst->cap ? dst->cap * 2 : 64;
        int *next = realloc(dst->v, (size_t)dst->cap * sizeof(dst->v[0]));
        if (!next) {
            perror("ds4: realloc");
            exit(1);
        }
        dst->v = next;
    }
    memmove(dst->v + pos + src->len, dst->v + pos,
            (size_t)(dst->len - pos) * sizeof(dst->v[0]));
    memcpy(dst->v + pos, src->v, (size_t)src->len * sizeof(src->v[0]));
    dst->len += src->len;
}

static void tokens_remove(ds4_tokens *dst, int pos, int n) {
    if (n <= 0 || pos < 0 || pos >= dst->len) return;
    if (pos + n > dst->len) n = dst->len - pos;
    memmove(dst->v + pos, dst->v + pos + n,
            (size_t)(dst->len - pos - n) * sizeof(dst->v[0]));
    dst->len -= n;
}

/* Insert/remove the Think Max prefix inside the existing transcript.  The
 * prefix lives after BOS, before any system/developer text, which mirrors the
 * API rendering path.  Changing it invalidates the session because every later
 * token position would otherwise refer to the wrong prefix. */
static void repl_chat_apply_max_prefix(ds4_engine *engine, repl_chat *chat, bool enable) {
    if (enable && chat->max_prefix_tokens == 0) {
        ds4_tokens prefix = {0};
        ds4_chat_append_max_effort_prefix(engine, &prefix);
        tokens_insert(&chat->transcript, 1, &prefix);
        chat->max_prefix_tokens = prefix.len;
        ds4_tokens_free(&prefix);
        if (chat->session) ds4_session_invalidate(chat->session);
    } else if (!enable && chat->max_prefix_tokens > 0) {
        tokens_remove(&chat->transcript, 1, chat->max_prefix_tokens);
        chat->max_prefix_tokens = 0;
        if (chat->session) ds4_session_invalidate(chat->session);
    }
}
```<｜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_cli.c

```c
tokens_remove(&chat->transcript, 1, chat->max_prefix_tokens);
        chat->max_prefix_tokens = 0;
        if (chat->session) ds4_session_invalidate(chat->session);
    }
}

static int repl_chat_create_session(ds4_engine *engine, repl_chat *chat, int ctx_size) {
    ds4_session *session = NULL;
    if (ds4_session_create(&session, engine, ctx_size) != 0) {
        fprintf(stderr, "ds4: interactive chat KV cache requires a session backend\n");
        return 1;
    }
    if (chat->session) ds4_session_free(chat->session);
    chat->session = session;
    chat->ctx_size = ctx_size;
    return 0;
}

static int repl_chat_init(ds4_engine *engine, repl_chat *chat, const cli_config *cfg) {
    memset(chat, 0, sizeof(*chat));
    ds4_chat_begin(engine, &chat->transcript);
    repl_chat_apply_max_prefix(engine, chat,
                               cli_effective_think_mode(&cfg->gen) == DS4_THINK_MAX);
    if (cfg->gen.system && cfg->gen.system[0]) {
        ds4_chat_append_message(engine, &chat->transcript, "system", cfg->gen.system);
    }
    return repl_chat_create_session(engine, chat, cfg->gen.ctx_size);
}

static void repl_chat_free(repl_chat *chat) {
    if (!chat) return;
    ds4_session_free(chat->session);
    ds4_tokens_free(&chat->transcript);
    memset(chat, 0, sizeof(*chat));
}

static int repl_chat_set_ctx(ds4_engine *engine, repl_chat *chat, int ctx_size) {
    ds4_session_free(chat->session);
    chat->session = NULL;
    chat->ctx_size = 0;
    return repl_chat_create_session(engine, chat, ctx_size);
}

/* Run one interactive turn.  The transcript is tentatively extended with user
 * and assistant markers, then ds4_session_sync() decides whether this is a KV
 * continuation.  If prompt processing fails, the transcript rolls back before
 * returning to the prompt. */
static int run_chat_turn(ds4_engine *engine, cli_config *cfg, repl_chat *chat, const char *user_text) {
    if (!chat->session) {
        fprintf(stderr, "ds4: no active interactive KV cache\n");
        return 1;
    }

    ds4_think_mode think_mode = ds4_think_mode_for_context(cfg->gen.think_mode,
                                                           chat->ctx_size);
    repl_chat_apply_max_prefix(engine, chat, think_mode == DS4_THINK_MAX);
    const int rollback_len = chat->transcript.len;
    ds4_chat_append_message(engine, &chat->transcript, "user", user_text);
    ds4_chat_append_assistant_prefix(engine, &chat->transcript, think_mode);

    const int old_pos = ds4_session_pos(chat->session);
```

<｜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_cli.c

```c
tokens_remove(&chat->transcript, 1, chat->max_prefix_tokens);
        chat->max_prefix_tokens = 0;
        if (chat->session) ds4_session_invalidate(chat->session);
    }
}

static int repl_chat_create_session(ds4_engine *engine, repl_chat *chat, int ctx_size) {
    ds4_session *session = NULL;
    if (ds4_session_create(&session, engine, ctx_size) != 0) {
        fprintf(stderr, "ds4: interactive chat KV cache requires a session backend\n");
        return 1;
    }
    if (chat->session) ds4_session_free(chat->session);
    chat->session = session;
    chat->ctx_size = ctx_size;
    return 0;
}

static int repl_chat_init(ds4_engine *engine, repl_chat *chat, const cli_config *cfg) {
    memset(chat, 0, sizeof(*chat));
    ds4_chat_begin(engine, &chat->transcript);
    repl_chat_apply_max_prefix(engine, chat,
                               cli_effective_think_mode(&cfg->gen) == DS4_THINK_MAX);
    if (cfg->gen.system && cfg->gen.system[0]) {
        ds4_chat_append_message(engine, &chat->transcript, "system", cfg->gen.system);
    }
    return repl_chat_create_session(engine, chat, cfg->gen.ctx_size);
}

static void repl_chat_free(repl_chat *chat) {
    if (!chat) return;
    ds4_session_free(chat->session);
    ds4_tokens_free(&chat->transcript);
    memset(chat, 0, sizeof(*chat));
}

static int repl_chat_set_ctx(ds4_engine *engine, repl_chat *chat, int ctx_size) {
    ds4_session_free(chat->session);
    chat->session = NULL;
    chat->ctx_size = 0;
    return repl_chat_create_session(engine, chat, ctx_size);
}

/* Run one interactive turn.  The transcript is tentatively extended with user
 * and assistant markers, then ds4_session_sync() decides whether this is a KV
 * continuation.  If prompt processing fails, the transcript rolls back before
 * returning to the prompt. */
static int run_chat_turn(ds4_engine *engine, cli_config *cfg, repl_chat *chat, const char *user_text) {
    if (!chat->session) {
        fprintf(stderr, "ds4: no active interactive KV cache\n");
        return 1;
    }

    ds4_think_mode think_mode = ds4_think_mode_for_context(cfg->gen.think_mode,
                                                           chat->ctx_size);
    repl_chat_apply_max_prefix(engine, chat, think_mode == DS4_THINK_MAX);
    const int rollback_len = chat->transcript.len;
    ds4_chat_append_message(engine, &chat->transcript, "user", user_text);
    ds4_chat_append_assistant_prefix(engine, &chat->transcript, think_mode);

    const int old_pos = ds4_session_pos(chat->session);
```<｜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_cli.c

```c
tokens_remove(&chat->transcript, 1, chat->max_prefix_tokens);
        chat->max_prefix_tokens = 0;
        if (chat->session) ds4_session_invalidate(chat->session);
    }
}

static int repl_chat_create_session(ds4_engine *engine, repl_chat *chat, int ctx_size) {
    ds4_session *session = NULL;
    if (ds4_session_create(&session, engine, ctx_size) != 0) {
        fprintf(stderr, "ds4: interactive chat KV cache requires a session backend\n");
        return 1;
    }
    if (chat->session) ds4_session_free(chat->session);
    chat->session = session;
    chat->ctx_size = ctx_size;
    return 0;
}

static int repl_chat_init(ds4_engine *engine, repl_chat *chat, const cli_config *cfg) {
    memset(chat, 0, sizeof(*chat));
    ds4_chat_begin(engine, &chat->transcript);
    repl_chat_apply_max_prefix(engine, chat,
                               cli_effective_think_mode(&cfg->gen) == DS4_THINK_MAX);
    if (cfg->gen.system && cfg->gen.system[0]) {
        ds4_chat_append_message(engine, &chat->transcript, "system", cfg->gen.system);
    }
    return repl_chat_create_session(engine, chat, cfg->gen.ctx_size);
}

static void repl_chat_free(repl_chat *chat) {
    if (!chat) return;
    ds4_session_free(chat->session);
    ds4_tokens_free(&chat->transcript);
    memset(chat, 0, sizeof(*chat));
}

static int repl_chat_set_ctx(ds4_engine *engine, repl_chat *chat, int ctx_size) {
    ds4_session_free(chat->session);
    chat->session = NULL;
    chat->ctx_size = 0;
    return repl_chat_create_session(engine, chat, ctx_size);
}

/* Run one interactive turn.  The transcript is tentatively extended with user
 * and assistant markers, then ds4_session_sync() decides whether this is a KV
 * continuation.  If prompt processing fails, the transcript rolls back before
 * returning to the prompt. */
static int run_chat_turn(ds4_engine *engine, cli_config *cfg, repl_chat *chat, const char *user_text) {
    if (!chat->session) {
        fprintf(stderr, "ds4: no active interactive KV cache\n");
        return 1;
    }

    ds4_think_mode think_mode = ds4_think_mode_for_context(cfg->gen.think_mode,
                                                           chat->ctx_size);
    repl_chat_apply_max_prefix(engine, chat, think_mode == DS4_THINK_MAX);
    const int rollback_len = chat->transcript.len;
    ds4_chat_append_message(engine, &chat->transcript, "user", user_text);
    ds4_chat_append_assistant_prefix(engine, &chat->transcript, think_mode);

    const int old_pos = ds4_session_pos(chat->session);
```

<｜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_cli.c

```c
tokens_remove(&chat->transcript, 1, chat->max_prefix_tokens);
        chat->max_prefix_tokens = 0;
        if (chat->session) ds4_session_invalidate(chat->session);
    }
}

static int repl_chat_create_session(ds4_engine *engine, repl_chat *chat, int ctx_size) {
    ds4_session *session = NULL;
    if (ds4_session_create(&session, engine, ctx_size) != 0) {
        fprintf(stderr, "ds4: interactive chat KV cache requires a session backend\n");
        return 1;
    }
    if (chat->session) ds4_session_free(chat->session);
    chat->session = session;
    chat->ctx_size = ctx_size;
    return 0;
}

static int repl_chat_init(ds4_engine *engine, repl_chat *chat, const cli_config *cfg) {
    memset(chat, 0, sizeof(*chat));
    ds4_chat_begin(engine, &chat->transcript);
    repl_chat_apply_max_prefix(engine, chat,
                               cli_effective_think_mode(&cfg->gen) == DS4_THINK_MAX);
    if (cfg->gen.system && cfg->gen.system[0]) {
        ds4_chat_append_message(engine, &chat->transcript, "system", cfg->gen.system);
    }
    return repl_chat_create_session(engine, chat, cfg->gen.ctx_size);
}

static void repl_chat_free(repl_chat *chat) {
    if (!chat) return;
    ds4_session_free(chat->session);
    ds4_tokens_free(&chat->transcript);
    memset(chat, 0, sizeof(*chat));
}

static int repl_chat_set_ctx(ds4_engine *engine, repl_chat *chat, int ctx_size) {
    ds4_session_free(chat->session);
    chat->session = NULL;
    chat->ctx_size = 0;
    return repl_chat_create_session(engine, chat, ctx_size);
}

/* Run one interactive turn.  The transcript is tentatively extended with user
 * and assistant markers, then ds4_session_sync() decides whether this is a KV
 * continuation.  If prompt processing fails, the transcript rolls back before
 * returning to the prompt. */
static int run_chat_turn(ds4_engine *engine, cli_config *cfg, repl_chat *chat, const char *user_text) {
    if (!chat->session) {
        fprintf(stderr, "ds4: no active interactive KV cache\n");
        return 1;
    }

    ds4_think_mode think_mode = ds4_think_mode_for_context(cfg->gen.think_mode,
                                                           chat->ctx_size);
    repl_chat_apply_max_prefix(engine, chat, think_mode == DS4_THINK_MAX);
    const int rollback_len = chat->transcript.len;
    ds4_chat_append_message(engine, &chat->transcript, "user", user_text);
    ds4_chat_append_assistant_prefix(engine, &chat->transcript, think_mode);

    const int old_pos = ds4_session_pos(chat->session);
```<｜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_cli.c

```c
engine, &chat->transcript, "user", user_text);
    ds4_chat_append_assistant_prefix(engine, &chat->transcript, think_mode);

    const int old_pos = ds4_session_pos(chat->session);
    const int common = ds4_session_common_prefix(chat->session, &chat->transcript);
    const int cached = common == old_pos && chat->transcript.len >= old_pos ? common : 0;
    const int suffix = chat->transcript.len - cached;

    char err[160];
    cli_prefill_progress progress = {
        .base_tokens = cached,
        .input_tokens = suffix,
        .use_color = ds4_log_is_tty(stderr),
    };
    const double t_prefill0 = cli_now_sec();
    ds4_session_set_progress(chat->session, cli_prefill_progress_cb, &progress);
    if (ds4_session_sync(chat->session, &chat->transcript, err, sizeof(err)) != 0) {
        ds4_session_set_progress(chat->session, NULL, NULL);
        chat->transcript.len = rollback_len;
        fprintf(stderr, "ds4: prompt processing failed: %s\n", err);
        return 1;
    }
    ds4_session_set_progress(chat->session, NULL, NULL);
    const double t_prefill1 = cli_now_sec();

    token_printer printer = {
        .engine = engine,
        .fp = stdout,
        .format_thinking = ds4_think_mode_enabled(think_mode),
        .in_think = ds4_think_mode_enabled(think_mode),
        .use_color = isatty(fileno(stdout)) != 0,
        .last_output_newline = true,
    };

    int max_tokens = cfg->gen.n_predict;
    int room = ds4_session_ctx(chat->session) - ds4_session_pos(chat->session);
    if (room <= 1) max_tokens = 0;
    else if (max_tokens > room - 1) max_tokens = room - 1;

    uint64_t rng = cfg->gen.seed ? cfg->gen.seed :
        ((uint64_t)time(NULL) ^ ((uint64_t)getpid() << 32) ^ (uint64_t)clock());
    int generated = 0;
    const double t_decode0 = cli_now_sec();
    while (generated < max_tokens && !cli_interrupt_requested()) {
        int token = ds4_session_sample(chat->session,
                                       cfg->gen.temperature,
                                       0,
                                       cfg->gen.top_p,
                                       0.0f,
                                       &rng);
        if (token == ds4_token_eos(engine)) break;

        int toks[17];
        int ntok = 0;
        if (cfg->gen.temperature <= 0.0f && ds4_engine_mtp_draft_tokens(engine) > 1 &&
            getenv("DS4_MTP_SPEC_DISABLE") == NULL) {
            ntok = ds4_session_eval_speculative_argmax(chat->session,
                                                       token,
```

<｜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_cli.c

```c
engine, &chat->transcript, "user", user_text);
    ds4_chat_append_assistant_prefix(engine, &chat->transcript, think_mode);

    const int old_pos = ds4_session_pos(chat->session);
    const int common = ds4_session_common_prefix(chat->session, &chat->transcript);
    const int cached = common == old_pos && chat->transcript.len >= old_pos ? common : 0;
    const int suffix = chat->transcript.len - cached;

    char err[160];
    cli_prefill_progress progress = {
        .base_tokens = cached,
        .input_tokens = suffix,
        .use_color = ds4_log_is_tty(stderr),
    };
    const double t_prefill0 = cli_now_sec();
    ds4_session_set_progress(chat->session, cli_prefill_progress_cb, &progress);
    if (ds4_session_sync(chat->session, &chat->transcript, err, sizeof(err)) != 0) {
        ds4_session_set_progress(chat->session, NULL, NULL);
        chat->transcript.len = rollback_len;
        fprintf(stderr, "ds4: prompt processing failed: %s\n", err);
        return 1;
    }
    ds4_session_set_progress(chat->session, NULL, NULL);
    const double t_prefill1 = cli_now_sec();

    token_printer printer = {
        .engine = engine,
        .fp = stdout,
        .format_thinking = ds4_think_mode_enabled(think_mode),
        .in_think = ds4_think_mode_enabled(think_mode),
        .use_color = isatty(fileno(stdout)) != 0,
        .last_output_newline = true,
    };

    int max_tokens = cfg->gen.n_predict;
    int room = ds4_session_ctx(chat->session) - ds4_session_pos(chat->session);
    if (room <= 1) max_tokens = 0;
    else if (max_tokens > room - 1) max_tokens = room - 1;

    uint64_t rng = cfg->gen.seed ? cfg->gen.seed :
        ((uint64_t)time(NULL) ^ ((uint64_t)getpid() << 32) ^ (uint64_t)clock());
    int generated = 0;
    const double t_decode0 = cli_now_sec();
    while (generated < max_tokens && !cli_interrupt_requested()) {
        int token = ds4_session_sample(chat->session,
                                       cfg->gen.temperature,
                                       0,
                                       cfg->gen.top_p,
                                       0.0f,
                                       &rng);
        if (token == ds4_token_eos(engine)) break;

        int toks[17];
        int ntok = 0;
        if (cfg->gen.temperature <= 0.0f && ds4_engine_mtp_draft_tokens(engine) > 1 &&
            getenv("DS4_MTP_SPEC_DISABLE") == NULL) {
            ntok = ds4_session_eval_speculative_argmax(chat->session,
                                                       token,
```<｜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_cli.c

```c
engine, &chat->transcript, "user", user_text);
    ds4_chat_append_assistant_prefix(engine, &chat->transcript, think_mode);

    const int old_pos = ds4_session_pos(chat->session);
    const int common = ds4_session_common_prefix(chat->session, &chat->transcript);
    const int cached = common == old_pos && chat->transcript.len >= old_pos ? common : 0;
    const int suffix = chat->transcript.len - cached;

    char err[160];
    cli_prefill_progress progress = {
        .base_tokens = cached,
        .input_tokens = suffix,
        .use_color = ds4_log_is_tty(stderr),
    };
    const double t_prefill0 = cli_now_sec();
    ds4_session_set_progress(chat->session, cli_prefill_progress_cb, &progress);
    if (ds4_session_sync(chat->session, &chat->transcript, err, sizeof(err)) != 0) {
        ds4_session_set_progress(chat->session, NULL, NULL);
        chat->transcript.len = rollback_len;
        fprintf(stderr, "ds4: prompt processing failed: %s\n", err);
        return 1;
    }
    ds4_session_set_progress(chat->session, NULL, NULL);
    const double t_prefill1 = cli_now_sec();

    token_printer printer = {
        .engine = engine,
        .fp = stdout,
        .format_thinking = ds4_think_mode_enabled(think_mode),
        .in_think = ds4_think_mode_enabled(think_mode),
        .use_color = isatty(fileno(stdout)) != 0,
        .last_output_newline = true,
    };

    int max_tokens = cfg->gen.n_predict;
    int room = ds4_session_ctx(chat->session) - ds4_session_pos(chat->session);
    if (room <= 1) max_tokens = 0;
    else if (max_tokens > room - 1) max_tokens = room - 1;

    uint64_t rng = cfg->gen.seed ? cfg->gen.seed :
        ((uint64_t)time(NULL) ^ ((uint64_t)getpid() << 32) ^ (uint64_t)clock());
    int generated = 0;
    const double t_decode0 = cli_now_sec();
    while (generated < max_tokens && !cli_interrupt_requested()) {
        int token = ds4_session_sample(chat->session,
                                       cfg->gen.temperature,
                                       0,
                                       cfg->gen.top_p,
                                       0.0f,
                                       &rng);
        if (token == ds4_token_eos(engine)) break;

        int toks[17];
        int ntok = 0;
        if (cfg->gen.temperature <= 0.0f && ds4_engine_mtp_draft_tokens(engine) > 1 &&
            getenv("DS4_MTP_SPEC_DISABLE") == NULL) {
            ntok = ds4_session_eval_speculative_argmax(chat->session,
                                                       token,
```

<｜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_cli.c

```c
engine, &chat->transcript, "user", user_text);
    ds4_chat_append_assistant_prefix(engine, &chat->transcript, think_mode);

    const int old_pos = ds4_session_pos(chat->session);
    const int common = ds4_session_common_prefix(chat->session, &chat->transcript);
    const int cached = common == old_pos && chat->transcript.len >= old_pos ? common : 0;
    const int suffix = chat->transcript.len - cached;

    char err[160];
    cli_prefill_progress progress = {
        .base_tokens = cached,
        .input_tokens = suffix,
        .use_color = ds4_log_is_tty(stderr),
    };
    const double t_prefill0 = cli_now_sec();
    ds4_session_set_progress(chat->session, cli_prefill_progress_cb, &progress);
    if (ds4_session_sync(chat->session, &chat->transcript, err, sizeof(err)) != 0) {
        ds4_session_set_progress(chat->session, NULL, NULL);
        chat->transcript.len = rollback_len;
        fprintf(stderr, "ds4: prompt processing failed: %s\n", err);
        return 1;
    }
    ds4_session_set_progress(chat->session, NULL, NULL);
    const double t_prefill1 = cli_now_sec();

    token_printer printer = {
        .engine = engine,
        .fp = stdout,
        .format_thinking = ds4_think_mode_enabled(think_mode),
        .in_think = ds4_think_mode_enabled(think_mode),
        .use_color = isatty(fileno(stdout)) != 0,
        .last_output_newline = true,
    };

    int max_tokens = cfg->gen.n_predict;
    int room = ds4_session_ctx(chat->session) - ds4_session_pos(chat->session);
    if (room <= 1) max_tokens = 0;
    else if (max_tokens > room - 1) max_tokens = room - 1;

    uint64_t rng = cfg->gen.seed ? cfg->gen.seed :
        ((uint64_t)time(NULL) ^ ((uint64_t)getpid() << 32) ^ (uint64_t)clock());
    int generated = 0;
    const double t_decode0 = cli_now_sec();
    while (generated < max_tokens && !cli_interrupt_requested()) {
        int token = ds4_session_sample(chat->session,
                                       cfg->gen.temperature,
                                       0,
                                       cfg->gen.top_p,
                                       0.0f,
                                       &rng);
        if (token == ds4_token_eos(engine)) break;

        int toks[17];
        int ntok = 0;
        if (cfg->gen.temperature <= 0.0f && ds4_engine_mtp_draft_tokens(engine) > 1 &&
            getenv("DS4_MTP_SPEC_DISABLE") == NULL) {
            ntok = ds4_session_eval_speculative_argmax(chat->session,
                                                       token,
```<｜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_cli.c

```c
getenv("DS4_MTP_SPEC_DISABLE") == NULL) {
            ntok = ds4_session_eval_speculative_argmax(chat->session,
                                                       token,
                                                       max_tokens - generated,
                                                       ds4_token_eos(engine),
                                                       toks,
                                                       (int)(sizeof(toks) / sizeof(toks[0])),
                                                       err,
                                                       sizeof(err));
            if (ntok < 0) {
                fprintf(stderr, "ds4: decode failed: %s\n", err);
                return 1;
            }
        } else {
            if (ds4_session_eval(chat->session, token, err, sizeof(err)) != 0) {
                fprintf(stderr, "ds4: decode failed: %s\n", err);
                return 1;
            }
            toks[0] = token;
            ntok = 1;
        }

        bool stop = false;
        for (int j = 0; j < ntok; j++) {
            if (toks[j] == ds4_token_eos(engine)) {
                stop = true;
                break;
            }
            size_t piece_len = 0;
            char *piece = ds4_token_text(engine, toks[j], &piece_len);
            ds4_tokens_push(&chat->transcript, toks[j]);
            token_printer_write_text(&printer, piece, piece_len);
            fflush(stdout);
            free(piece);
            generated++;
            if (generated >= max_tokens) break;
        }
        if (stop) break;
    }
    const double t_decode1 = cli_now_sec();
    generation_done(&printer);

    const bool interrupted = cli_interrupt_requested();
    if (interrupted && generated == 0) {
        chat->transcript.len = rollback_len;
        ds4_session_invalidate(chat->session);
    } else {
        ds4_tokens_push(&chat->transcript, ds4_token_eos(engine));
    }

    const double prefill_s = t_prefill1 - t_prefill0;
    const double decode_s = t_decode1 - t_decode0;
    if (interrupted) cli_interrupt_clear();
    ds4_log(stderr,
            DS4_LOG_TIMING,
            "ds4: prefill: %.2f t/s, generation: %.2f t/s\n",
            prefill_s > 0.0 ? (double)suffix / prefill_s : 0.0,
            decode_s > 0.0 ? (double)generated / decode_s : 0.0);
    return 0;
}

static int run_repl(ds4_engine *engine, cli_config *cfg) {
    repl_chat chat;
    if (repl_chat_init(engine, &chat, cfg) != 0) return 1;

    struct sigaction old_int;
    struct sigaction sa;
    memset(&sa, 0, sizeof(sa));
```

<｜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_cli.c

```c
getenv("DS4_MTP_SPEC_DISABLE") == NULL) {
            ntok = ds4_session_eval_speculative_argmax(chat->session,
                                                       token,
                                                       max_tokens - generated,
                                                       ds4_token_eos(engine),
                                                       toks,
                                                       (int)(sizeof(toks) / sizeof(toks[0])),
                                                       err,
                                                       sizeof(err));
            if (ntok < 0) {
                fprintf(stderr, "ds4: decode failed: %s\n", err);
                return 1;
            }
        } else {
            if (ds4_session_eval(chat->session, token, err, sizeof(err)) != 0) {
                fprintf(stderr, "ds4: decode failed: %s\n", err);
                return 1;
            }
            toks[0] = token;
            ntok = 1;
        }

        bool stop = false;
        for (int j = 0; j < ntok; j++) {
            if (toks[j] == ds4_token_eos(engine)) {
                stop = true;
                break;
            }
            size_t piece_len = 0;
            char *piece = ds4_token_text(engine, toks[j], &piece_len);
            ds4_tokens_push(&chat->transcript, toks[j]);
            token_printer_write_text(&printer, piece, piece_len);
            fflush(stdout);
            free(piece);
            generated++;
            if (generated >= max_tokens) break;
        }
        if (stop) break;
    }
    const double t_decode1 = cli_now_sec();
    generation_done(&printer);

    const bool interrupted = cli_interrupt_requested();
    if (interrupted && generated == 0) {
        chat->transcript.len = rollback_len;
        ds4_session_invalidate(chat->session);
    } else {
        ds4_tokens_push(&chat->transcript, ds4_token_eos(engine));
    }

    const double prefill_s = t_prefill1 - t_prefill0;
    const double decode_s = t_decode1 - t_decode0;
    if (interrupted) cli_interrupt_clear();
    ds4_log(stderr,
            DS4_LOG_TIMING,
            "ds4: prefill: %.2f t/s, generation: %.2f t/s\n",
            prefill_s > 0.0 ? (double)suffix / prefill_s : 0.0,
            decode_s > 0.0 ? (double)generated / decode_s : 0.0);
    return 0;
}

static int run_repl(ds4_engine *engine, cli_config *cfg) {
    repl_chat chat;
    if (repl_chat_init(engine, &chat, cfg) != 0) return 1;

    struct sigaction old_int;
    struct sigaction sa;
    memset(&sa, 0, sizeof(sa));
```<｜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_cli.c

```c
getenv("DS4_MTP_SPEC_DISABLE") == NULL) {
            ntok = ds4_session_eval_speculative_argmax(chat->session,
                                                       token,
                                                       max_tokens - generated,
                                                       ds4_token_eos(engine),
                                                       toks,
                                                       (int)(sizeof(toks) / sizeof(toks[0])),
                                                       err,
                                                       sizeof(err));
            if (ntok < 0) {
                fprintf(stderr, "ds4: decode failed: %s\n", err);
                return 1;
            }
        } else {
            if (ds4_session_eval(chat->session, token, err, sizeof(err)) != 0) {
                fprintf(stderr, "ds4: decode failed: %s\n", err);
                return 1;
            }
            toks[0] = token;
            ntok = 1;
        }

        bool stop = false;
        for (int j = 0; j < ntok; j++) {
            if (toks[j] == ds4_token_eos(engine)) {
                stop = true;
                break;
            }
            size_t piece_len = 0;
            char *piece = ds4_token_text(engine, toks[j], &piece_len);
            ds4_tokens_push(&chat->transcript, toks[j]);
            token_printer_write_text(&printer, piece, piece_len);
            fflush(stdout);
            free(piece);
            generated++;
            if (generated >= max_tokens) break;
        }
        if (stop) break;
    }
    const double t_decode1 = cli_now_sec();
    generation_done(&printer);

    const bool interrupted = cli_interrupt_requested();
    if (interrupted && generated == 0) {
        chat->transcript.len = rollback_len;
        ds4_session_invalidate(chat->session);
    } else {
        ds4_tokens_push(&chat->transcript, ds4_token_eos(engine));
    }

    const double prefill_s = t_prefill1 - t_prefill0;
    const double decode_s = t_decode1 - t_decode0;
    if (interrupted) cli_interrupt_clear();
    ds4_log(stderr,
            DS4_LOG_TIMING,
            "ds4: prefill: %.2f t/s, generation: %.2f t/s\n",
            prefill_s > 0.0 ? (double)suffix / prefill_s : 0.0,
            decode_s > 0.0 ? (double)generated / decode_s : 0.0);
    return 0;
}

static int run_repl(ds4_engine *engine, cli_config *cfg) {
    repl_chat chat;
    if (repl_chat_init(engine, &chat, cfg) != 0) return 1;

    struct sigaction old_int;
    struct sigaction sa;
    memset(&sa, 0, sizeof(sa));
```

<｜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_cli.c

```c
getenv("DS4_MTP_SPEC_DISABLE") == NULL) {
            ntok = ds4_session_eval_speculative_argmax(chat->session,
                                                       token,
                                                       max_tokens - generated,
                                                       ds4_token_eos(engine),
                                                       toks,
                                                       (int)(sizeof(toks) / sizeof(toks[0])),
                                                       err,
                                                       sizeof(err));
            if (ntok < 0) {
                fprintf(stderr, "ds4: decode failed: %s\n", err);
                return 1;
            }
        } else {
            if (ds4_session_eval(chat->session, token, err, sizeof(err)) != 0) {
                fprintf(stderr, "ds4: decode failed: %s\n", err);
                return 1;
            }
            toks[0] = token;
            ntok = 1;
        }

        bool stop = false;
        for (int j = 0; j < ntok; j++) {
            if (toks[j] == ds4_token_eos(engine)) {
                stop = true;
                break;
            }
            size_t piece_len = 0;
            char *piece = ds4_token_text(engine, toks[j], &piece_len);
            ds4_tokens_push(&chat->transcript, toks[j]);
            token_printer_write_text(&printer, piece, piece_len);
            fflush(stdout);
            free(piece);
            generated++;
            if (generated >= max_tokens) break;
        }
        if (stop) break;
    }
    const double t_decode1 = cli_now_sec();
    generation_done(&printer);

    const bool interrupted = cli_interrupt_requested();
    if (interrupted && generated == 0) {
        chat->transcript.len = rollback_len;
        ds4_session_invalidate(chat->session);
    } else {
        ds4_tokens_push(&chat->transcript, ds4_token_eos(engine));
    }

    const double prefill_s = t_prefill1 - t_prefill0;
    const double decode_s = t_decode1 - t_decode0;
    if (interrupted) cli_interrupt_clear();
    ds4_log(stderr,
            DS4_LOG_TIMING,
            "ds4: prefill: %.2f t/s, generation: %.2f t/s\n",
            prefill_s > 0.0 ? (double)suffix / prefill_s : 0.0,
            decode_s > 0.0 ? (double)generated / decode_s : 0.0);
    return 0;
}

static int run_repl(ds4_engine *engine, cli_config *cfg) {
    repl_chat chat;
    if (repl_chat_init(engine, &chat, cfg) != 0) return 1;

    struct sigaction old_int;
    struct sigaction sa;
    memset(&sa, 0, sizeof(sa));
```<｜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_cli.c

```c
onfig *cfg) {
    repl_chat chat;
    if (repl_chat_init(engine, &chat, cfg) != 0) return 1;

    struct sigaction old_int;
    struct sigaction sa;
    memset(&sa, 0, sizeof(sa));
    sigemptyset(&sa.sa_mask);
    sa.sa_handler = cli_sigint_handler;
    bool sigint_installed = sigaction(SIGINT, &sa, &old_int) == 0;
    cli_interrupt_clear();

    char hist[PATH_MAX];
    history_file_path(hist, sizeof(hist));
    linenoiseSetMultiLine(1);
    linenoiseHistorySetMaxLen(512);
    linenoiseHistoryLoad(hist);
    print_repl_help();

    int rc = 0;
    for (;;) {
        errno = 0;
        char *line = linenoise("ds4> ");
        if (!line) {
            if (errno == EAGAIN || cli_interrupt_requested()) {
                cli_interrupt_clear();
                continue;
            }
            break;
        }
        char *cmd = trim_inplace(line);
        if (!cmd[0]) {
            linenoiseFree(line);
            continue;
        }
        linenoiseHistoryAdd(cmd);
        linenoiseHistorySave(hist);

        if (!strcmp(cmd, "/help")) {
            print_repl_help();
        } else if (!strcmp(cmd, "/think")) {
            cfg->gen.think_mode = DS4_THINK_HIGH;
            repl_chat_apply_max_prefix(engine, &chat, false);
            puts("Thinking mode: high.");
        } else if (!strcmp(cmd, "/think-max")) {
            cfg->gen.think_mode = DS4_THINK_MAX;
            bool active = ds4_think_mode_for_context(cfg->gen.think_mode,
                                                     chat.ctx_size) == DS4_THINK_MAX;
            repl_chat_apply_max_prefix(engine, &chat, active);
            cli_warn_think_max_downgraded(&cfg->gen, "/think-max");
            printf("Thinking mode: %s.\n", active ? "max" : "high (ctx below 393216)");
        } else if (!strcmp(cmd, "/nothink")) {
            cfg->gen.think_mode = DS4_THINK_NONE;
            repl_chat_apply_max_prefix(engine, &chat, false);
            puts("Thinking mode: none.");
        } else if (!strncmp(cmd, "/ctx", 4) && (cmd[4] == '\0' || isspace((unsigned char)cmd[4]))) {
            char *arg = trim_inplace(cmd + 4);
            if (!arg[0]) {
                fprintf(stderr, "ds4: /ctx needs a positive integer\n");
            } else {
                cfg->gen.ctx_size = parse_int(arg, "/ctx");
                log_context_memory(cfg->engine.backend, cfg->gen.ctx_size);
                rc = repl_chat_set_ctx(engine, &chat, cfg->gen.ctx_size);
                if (rc != 0) {
                    linenoiseFree(line);
                    break;
                }
```

<｜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_cli.c

```c
onfig *cfg) {
    repl_chat chat;
    if (repl_chat_init(engine, &chat, cfg) != 0) return 1;

    struct sigaction old_int;
    struct sigaction sa;
    memset(&sa, 0, sizeof(sa));
    sigemptyset(&sa.sa_mask);
    sa.sa_handler = cli_sigint_handler;
    bool sigint_installed = sigaction(SIGINT, &sa, &old_int) == 0;
    cli_interrupt_clear();

    char hist[PATH_MAX];
    history_file_path(hist, sizeof(hist));
    linenoiseSetMultiLine(1);
    linenoiseHistorySetMaxLen(512);
    linenoiseHistoryLoad(hist);
    print_repl_help();

    int rc = 0;
    for (;;) {
        errno = 0;
        char *line = linenoise("ds4> ");
        if (!line) {
            if (errno == EAGAIN || cli_interrupt_requested()) {
                cli_interrupt_clear();
                continue;
            }
            break;
        }
        char *cmd = trim_inplace(line);
        if (!cmd[0]) {
            linenoiseFree(line);
            continue;
        }
        linenoiseHistoryAdd(cmd);
        linenoiseHistorySave(hist);

        if (!strcmp(cmd, "/help")) {
            print_repl_help();
        } else if (!strcmp(cmd, "/think")) {
            cfg->gen.think_mode = DS4_THINK_HIGH;
            repl_chat_apply_max_prefix(engine, &chat, false);
            puts("Thinking mode: high.");
        } else if (!strcmp(cmd, "/think-max")) {
            cfg->gen.think_mode = DS4_THINK_MAX;
            bool active = ds4_think_mode_for_context(cfg->gen.think_mode,
                                                     chat.ctx_size) == DS4_THINK_MAX;
            repl_chat_apply_max_prefix(engine, &chat, active);
            cli_warn_think_max_downgraded(&cfg->gen, "/think-max");
            printf("Thinking mode: %s.\n", active ? "max" : "high (ctx below 393216)");
        } else if (!strcmp(cmd, "/nothink")) {
            cfg->gen.think_mode = DS4_THINK_NONE;
            repl_chat_apply_max_prefix(engine, &chat, false);
            puts("Thinking mode: none.");
        } else if (!strncmp(cmd, "/ctx", 4) && (cmd[4] == '\0' || isspace((unsigned char)cmd[4]))) {
            char *arg = trim_inplace(cmd + 4);
            if (!arg[0]) {
                fprintf(stderr, "ds4: /ctx needs a positive integer\n");
            } else {
                cfg->gen.ctx_size = parse_int(arg, "/ctx");
                log_context_memory(cfg->engine.backend, cfg->gen.ctx_size);
                rc = repl_chat_set_ctx(engine, &chat, cfg->gen.ctx_size);
                if (rc != 0) {
                    linenoiseFree(line);
                    break;
                }
```<｜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_cli.c

```c
onfig *cfg) {
    repl_chat chat;
    if (repl_chat_init(engine, &chat, cfg) != 0) return 1;

    struct sigaction old_int;
    struct sigaction sa;
    memset(&sa, 0, sizeof(sa));
    sigemptyset(&sa.sa_mask);
    sa.sa_handler = cli_sigint_handler;
    bool sigint_installed = sigaction(SIGINT, &sa, &old_int) == 0;
    cli_interrupt_clear();

    char hist[PATH_MAX];
    history_file_path(hist, sizeof(hist));
    linenoiseSetMultiLine(1);
    linenoiseHistorySetMaxLen(512);
    linenoiseHistoryLoad(hist);
    print_repl_help();

    int rc = 0;
    for (;;) {
        errno = 0;
        char *line = linenoise("ds4> ");
        if (!line) {
            if (errno == EAGAIN || cli_interrupt_requested()) {
                cli_interrupt_clear();
                continue;
            }
            break;
        }
        char *cmd = trim_inplace(line);
        if (!cmd[0]) {
            linenoiseFree(line);
            continue;
        }
        linenoiseHistoryAdd(cmd);
        linenoiseHistorySave(hist);

        if (!strcmp(cmd, "/help")) {
            print_repl_help();
        } else if (!strcmp(cmd, "/think")) {
            cfg->gen.think_mode = DS4_THINK_HIGH;
            repl_chat_apply_max_prefix(engine, &chat, false);
            puts("Thinking mode: high.");
        } else if (!strcmp(cmd, "/think-max")) {
            cfg->gen.think_mode = DS4_THINK_MAX;
            bool active = ds4_think_mode_for_context(cfg->gen.think_mode,
                                                     chat.ctx_size) == DS4_THINK_MAX;
            repl_chat_apply_max_prefix(engine, &chat, active);
            cli_warn_think_max_downgraded(&cfg->gen, "/think-max");
            printf("Thinking mode: %s.\n", active ? "max" : "high (ctx below 393216)");
        } else if (!strcmp(cmd, "/nothink")) {
            cfg->gen.think_mode = DS4_THINK_NONE;
            repl_chat_apply_max_prefix(engine, &chat, false);
            puts("Thinking mode: none.");
        } else if (!strncmp(cmd, "/ctx", 4) && (cmd[4] == '\0' || isspace((unsigned char)cmd[4]))) {
            char *arg = trim_inplace(cmd + 4);
            if (!arg[0]) {
                fprintf(stderr, "ds4: /ctx needs a positive integer\n");
            } else {
                cfg->gen.ctx_size = parse_int(arg, "/ctx");
                log_context_memory(cfg->engine.backend, cfg->gen.ctx_size);
                rc = repl_chat_set_ctx(engine, &chat, cfg->gen.ctx_size);
                if (rc != 0) {
                    linenoiseFree(line);
                    break;
                }
```

<｜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_cli.c

```c
onfig *cfg) {
    repl_chat chat;
    if (repl_chat_init(engine, &chat, cfg) != 0) return 1;

    struct sigaction old_int;
    struct sigaction sa;
    memset(&sa, 0, sizeof(sa));
    sigemptyset(&sa.sa_mask);
    sa.sa_handler = cli_sigint_handler;
    bool sigint_installed = sigaction(SIGINT, &sa, &old_int) == 0;
    cli_interrupt_clear();

    char hist[PATH_MAX];
    history_file_path(hist, sizeof(hist));
    linenoiseSetMultiLine(1);
    linenoiseHistorySetMaxLen(512);
    linenoiseHistoryLoad(hist);
    print_repl_help();

    int rc = 0;
    for (;;) {
        errno = 0;
        char *line = linenoise("ds4> ");
        if (!line) {
            if (errno == EAGAIN || cli_interrupt_requested()) {
                cli_interrupt_clear();
                continue;
            }
            break;
        }
        char *cmd = trim_inplace(line);
        if (!cmd[0]) {
            linenoiseFree(line);
            continue;
        }
        linenoiseHistoryAdd(cmd);
        linenoiseHistorySave(hist);

        if (!strcmp(cmd, "/help")) {
            print_repl_help();
        } else if (!strcmp(cmd, "/think")) {
            cfg->gen.think_mode = DS4_THINK_HIGH;
            repl_chat_apply_max_prefix(engine, &chat, false);
            puts("Thinking mode: high.");
        } else if (!strcmp(cmd, "/think-max")) {
            cfg->gen.think_mode = DS4_THINK_MAX;
            bool active = ds4_think_mode_for_context(cfg->gen.think_mode,
                                                     chat.ctx_size) == DS4_THINK_MAX;
            repl_chat_apply_max_prefix(engine, &chat, active);
            cli_warn_think_max_downgraded(&cfg->gen, "/think-max");
            printf("Thinking mode: %s.\n", active ? "max" : "high (ctx below 393216)");
        } else if (!strcmp(cmd, "/nothink")) {
            cfg->gen.think_mode = DS4_THINK_NONE;
            repl_chat_apply_max_prefix(engine, &chat, false);
            puts("Thinking mode: none.");
        } else if (!strncmp(cmd, "/ctx", 4) && (cmd[4] == '\0' || isspace((unsigned char)cmd[4]))) {
            char *arg = trim_inplace(cmd + 4);
            if (!arg[0]) {
                fprintf(stderr, "ds4: /ctx needs a positive integer\n");
            } else {
                cfg->gen.ctx_size = parse_int(arg, "/ctx");
                log_context_memory(cfg->engine.backend, cfg->gen.ctx_size);
                rc = repl_chat_set_ctx(engine, &chat, cfg->gen.ctx_size);
                if (rc != 0) {
                    linenoiseFree(line);
                    break;
                }
```<｜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_cli.c

```c
rc = repl_chat_set_ctx(engine, &chat, cfg->gen.ctx_size);
                if (rc != 0) {
                    linenoiseFree(line);
                    break;
                }
                bool active = ds4_think_mode_for_context(cfg->gen.think_mode,
                                                         chat.ctx_size) == DS4_THINK_MAX;
                repl_chat_apply_max_prefix(engine, &chat, active);
                cli_warn_think_max_downgraded(&cfg->gen, "/ctx");
            }
        } else if (!strcmp(cmd, "/quit") || !strcmp(cmd, "/exit")) {
            linenoiseFree(line);
            break;
        } else if (!strncmp(cmd, "/read", 5) && (cmd[5] == '\0' || isspace((unsigned char)cmd[5]))) {
            char *path = trim_inplace(cmd + 5);
            if (!path[0]) {
                fprintf(stderr, "ds4: /read needs a file path\n");
            } else {
                char *prompt = read_prompt_file(path, false);
                if (prompt) {
                    rc = run_chat_turn(engine, cfg, &chat, prompt);
                    free(prompt);
                }
            }
        } else if (cmd[0] == '/') {
            fprintf(stderr, "ds4: unknown command: %s\n", cmd);
            fprintf(stderr, "ds4: type /help for commands\n");
        } else {
            rc = run_chat_turn(engine, cfg, &chat, cmd);
        }
        linenoiseFree(line);
    }
    if (sigint_installed) sigaction(SIGINT, &old_int, NULL);
    repl_chat_free(&chat);
    return rc;
}

static const char *need_arg(int *i, int argc, char **argv, const char *opt) {
    if (*i + 1 >= argc) {
        fprintf(stderr, "ds4: missing value for %s\n", opt);
        exit(2);
    }
    return argv[++(*i)];
}

static char *read_prompt_file(const char *path, bool fatal) {
    FILE *fp = fopen(path, "rb");
    if (!fp) {
        fprintf(stderr, "ds4: failed to open prompt file: %s\n", path);
        if (fatal) exit(2);
        return NULL;
    }
    if (fseek(fp, 0, SEEK_END) != 0) {
        fprintf(stderr, "ds4: failed to seek prompt file: %s\n", path);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
    long len = ftell(fp);
    if (len < 0) {
        fprintf(stderr, "ds4: failed to size prompt file: %s\n", path);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
    rewind(fp);

    char *buf = malloc((size_t)len + 1);
    if (!buf) {
        fprintf(stderr, "ds4: out of memory reading prompt file: %s\n", path);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
```

<｜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_cli.c

```c
rc = repl_chat_set_ctx(engine, &chat, cfg->gen.ctx_size);
                if (rc != 0) {
                    linenoiseFree(line);
                    break;
                }
                bool active = ds4_think_mode_for_context(cfg->gen.think_mode,
                                                         chat.ctx_size) == DS4_THINK_MAX;
                repl_chat_apply_max_prefix(engine, &chat, active);
                cli_warn_think_max_downgraded(&cfg->gen, "/ctx");
            }
        } else if (!strcmp(cmd, "/quit") || !strcmp(cmd, "/exit")) {
            linenoiseFree(line);
            break;
        } else if (!strncmp(cmd, "/read", 5) && (cmd[5] == '\0' || isspace((unsigned char)cmd[5]))) {
            char *path = trim_inplace(cmd + 5);
            if (!path[0]) {
                fprintf(stderr, "ds4: /read needs a file path\n");
            } else {
                char *prompt = read_prompt_file(path, false);
                if (prompt) {
                    rc = run_chat_turn(engine, cfg, &chat, prompt);
                    free(prompt);
                }
            }
        } else if (cmd[0] == '/') {
            fprintf(stderr, "ds4: unknown command: %s\n", cmd);
            fprintf(stderr, "ds4: type /help for commands\n");
        } else {
            rc = run_chat_turn(engine, cfg, &chat, cmd);
        }
        linenoiseFree(line);
    }
    if (sigint_installed) sigaction(SIGINT, &old_int, NULL);
    repl_chat_free(&chat);
    return rc;
}

static const char *need_arg(int *i, int argc, char **argv, const char *opt) {
    if (*i + 1 >= argc) {
        fprintf(stderr, "ds4: missing value for %s\n", opt);
        exit(2);
    }
    return argv[++(*i)];
}

static char *read_prompt_file(const char *path, bool fatal) {
    FILE *fp = fopen(path, "rb");
    if (!fp) {
        fprintf(stderr, "ds4: failed to open prompt file: %s\n", path);
        if (fatal) exit(2);
        return NULL;
    }
    if (fseek(fp, 0, SEEK_END) != 0) {
        fprintf(stderr, "ds4: failed to seek prompt file: %s\n", path);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
    long len = ftell(fp);
    if (len < 0) {
        fprintf(stderr, "ds4: failed to size prompt file: %s\n", path);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
    rewind(fp);

    char *buf = malloc((size_t)len + 1);
    if (!buf) {
        fprintf(stderr, "ds4: out of memory reading prompt file: %s\n", path);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
```<｜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_cli.c

```c
rc = repl_chat_set_ctx(engine, &chat, cfg->gen.ctx_size);
                if (rc != 0) {
                    linenoiseFree(line);
                    break;
                }
                bool active = ds4_think_mode_for_context(cfg->gen.think_mode,
                                                         chat.ctx_size) == DS4_THINK_MAX;
                repl_chat_apply_max_prefix(engine, &chat, active);
                cli_warn_think_max_downgraded(&cfg->gen, "/ctx");
            }
        } else if (!strcmp(cmd, "/quit") || !strcmp(cmd, "/exit")) {
            linenoiseFree(line);
            break;
        } else if (!strncmp(cmd, "/read", 5) && (cmd[5] == '\0' || isspace((unsigned char)cmd[5]))) {
            char *path = trim_inplace(cmd + 5);
            if (!path[0]) {
                fprintf(stderr, "ds4: /read needs a file path\n");
            } else {
                char *prompt = read_prompt_file(path, false);
                if (prompt) {
                    rc = run_chat_turn(engine, cfg, &chat, prompt);
                    free(prompt);
                }
            }
        } else if (cmd[0] == '/') {
            fprintf(stderr, "ds4: unknown command: %s\n", cmd);
            fprintf(stderr, "ds4: type /help for commands\n");
        } else {
            rc = run_chat_turn(engine, cfg, &chat, cmd);
        }
        linenoiseFree(line);
    }
    if (sigint_installed) sigaction(SIGINT, &old_int, NULL);
    repl_chat_free(&chat);
    return rc;
}

static const char *need_arg(int *i, int argc, char **argv, const char *opt) {
    if (*i + 1 >= argc) {
        fprintf(stderr, "ds4: missing value for %s\n", opt);
        exit(2);
    }
    return argv[++(*i)];
}

static char *read_prompt_file(const char *path, bool fatal) {
    FILE *fp = fopen(path, "rb");
    if (!fp) {
        fprintf(stderr, "ds4: failed to open prompt file: %s\n", path);
        if (fatal) exit(2);
        return NULL;
    }
    if (fseek(fp, 0, SEEK_END) != 0) {
        fprintf(stderr, "ds4: failed to seek prompt file: %s\n", path);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
    long len = ftell(fp);
    if (len < 0) {
        fprintf(stderr, "ds4: failed to size prompt file: %s\n", path);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
    rewind(fp);

    char *buf = malloc((size_t)len + 1);
    if (!buf) {
        fprintf(stderr, "ds4: out of memory reading prompt file: %s\n", path);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
```

<｜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_cli.c

```c
rc = repl_chat_set_ctx(engine, &chat, cfg->gen.ctx_size);
                if (rc != 0) {
                    linenoiseFree(line);
                    break;
                }
                bool active = ds4_think_mode_for_context(cfg->gen.think_mode,
                                                         chat.ctx_size) == DS4_THINK_MAX;
                repl_chat_apply_max_prefix(engine, &chat, active);
                cli_warn_think_max_downgraded(&cfg->gen, "/ctx");
            }
        } else if (!strcmp(cmd, "/quit") || !strcmp(cmd, "/exit")) {
            linenoiseFree(line);
            break;
        } else if (!strncmp(cmd, "/read", 5) && (cmd[5] == '\0' || isspace((unsigned char)cmd[5]))) {
            char *path = trim_inplace(cmd + 5);
            if (!path[0]) {
                fprintf(stderr, "ds4: /read needs a file path\n");
            } else {
                char *prompt = read_prompt_file(path, false);
                if (prompt) {
                    rc = run_chat_turn(engine, cfg, &chat, prompt);
                    free(prompt);
                }
            }
        } else if (cmd[0] == '/') {
            fprintf(stderr, "ds4: unknown command: %s\n", cmd);
            fprintf(stderr, "ds4: type /help for commands\n");
        } else {
            rc = run_chat_turn(engine, cfg, &chat, cmd);
        }
        linenoiseFree(line);
    }
    if (sigint_installed) sigaction(SIGINT, &old_int, NULL);
    repl_chat_free(&chat);
    return rc;
}

static const char *need_arg(int *i, int argc, char **argv, const char *opt) {
    if (*i + 1 >= argc) {
        fprintf(stderr, "ds4: missing value for %s\n", opt);
        exit(2);
    }
    return argv[++(*i)];
}

static char *read_prompt_file(const char *path, bool fatal) {
    FILE *fp = fopen(path, "rb");
    if (!fp) {
        fprintf(stderr, "ds4: failed to open prompt file: %s\n", path);
        if (fatal) exit(2);
        return NULL;
    }
    if (fseek(fp, 0, SEEK_END) != 0) {
        fprintf(stderr, "ds4: failed to seek prompt file: %s\n", path);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
    long len = ftell(fp);
    if (len < 0) {
        fprintf(stderr, "ds4: failed to size prompt file: %s\n", path);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
    rewind(fp);

    char *buf = malloc((size_t)len + 1);
    if (!buf) {
        fprintf(stderr, "ds4: out of memory reading prompt file: %s\n", path);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
```<｜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_cli.c

```c
)len + 1);
    if (!buf) {
        fprintf(stderr, "ds4: out of memory reading prompt file: %s\n", path);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
    size_t nread = fread(buf, 1, (size_t)len, fp);
    if (nread != (size_t)len) {
        fprintf(stderr, "ds4: failed to read prompt file: %s\n", path);
        free(buf);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
    if (fclose(fp) != 0) {
        fprintf(stderr, "ds4: failed to close prompt file: %s\n", path);
        free(buf);
        if (fatal) exit(2);
        return NULL;
    }
    buf[len] = '\0';
    return buf;
}

static cli_config parse_options(int argc, char **argv) {
    cli_config c = {
        .engine = {
            .model_path = "ds4flash.gguf",
            .backend = default_backend(),
            .mtp_draft_tokens = 1,
            .mtp_margin = 3.0f,
        },
        .gen = {
            .prompt = NULL,
            .system = "You are a helpful assistant",
            .n_predict = 50000,
            .ctx_size = 32768,
            .temperature = 1.0f,
            .top_p = 1.0f,
            .dump_logprobs_top_k = 20,
            .think_mode = DS4_THINK_HIGH,
        },
    };

    bool directional_steering_scale_set = false;
    for (int i = 1; i < argc; i++) {
        const char *arg = argv[i];
        if (!strcmp(arg, "-h") || !strcmp(arg, "--help")) {
            usage(stdout);
            exit(0);
        } else if (!strcmp(arg, "-p") || !strcmp(arg, "--prompt")) {
            if (c.gen.prompt) {
                fprintf(stderr, "ds4: specify only one prompt source\n");
                exit(2);
            }
            c.gen.prompt = need_arg(&i, argc, argv, arg);
        } else if (!strcmp(arg, "--prompt-file")) {
            if (c.gen.prompt) {
                fprintf(stderr, "ds4: specify only one prompt source\n");
                exit(2);
            }
            c.prompt_owned = read_prompt_file(need_arg(&i, argc, argv, arg), true);
            c.gen.prompt = c.prompt_owned;
        } else if (!strcmp(arg, "-sys") || !strcmp(arg, "--system")) {
            c.gen.system = need_arg(&i, argc, argv, arg);
        } else if (!strcmp(arg, "-m") || !strcmp(arg, "--model")) {
            c.engine.model_path = need_arg(&i, argc, argv, arg);
        } else if (!strcmp(arg, "--mtp")) {
            c.engine.mtp_path = need_arg(&i, argc, argv, arg);
        } else if (!strcmp(arg, "--mtp-draft")) {
            c.engine.mtp_draft_tokens = parse_int(need_arg(&i, argc, argv, arg), arg);
```

<｜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_cli.c

```c
)len + 1);
    if (!buf) {
        fprintf(stderr, "ds4: out of memory reading prompt file: %s\n", path);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
    size_t nread = fread(buf, 1, (size_t)len, fp);
    if (nread != (size_t)len) {
        fprintf(stderr, "ds4: failed to read prompt file: %s\n", path);
        free(buf);
        fclose(fp);
        if (fatal) exit(2);
        return NULL;
    }
    if (fclose(fp) != 0) {
        fprintf(stderr, "ds4: failed to close prompt file: %s\n", path);
        free(buf);
        if (fatal) exit(2);
        return NULL;
    }
    buf[len] = '\0';
    return buf;
}

static cli_config parse_options(int argc, char **argv) {
    cli_config c = {
        .engine = {
            .model_path = "ds4flash.gguf",
            .backend = default_backend(),
            .mtp_draft_tokens = 1,
            .mtp_margin = 3.0f,
        },
        .gen = {
            .prompt = NULL,
            .system = "You are a helpful assistant",
            .n_predict = 50000,
            .ctx_size = 32768,
            .temperature = 1.0f,
            .top_p = 1.0f,
            .dump_logprobs_top_k = 20,
            .think_mode = DS4_THINK_HIGH,
        },
    };

    bool directional_steering_scale_set = false;
    for (int i = 1; i < argc; i++) {
        const char *arg = argv[i];
        if (!strcmp(arg, "-h") || !strcmp(arg, "--help")) {
            usage(stdout);
            exit(0);
        } else if (!strcmp(arg, "-p") || !strcmp(arg, "--prompt")) {
            if (c.gen.prompt) {
                fprintf(stderr, "ds4: specify only one prompt source\n");
                exit(2);
            }
            c.gen.prompt = need_arg(&i, argc, argv, arg);
        } else if (!strcmp(arg, "--prompt-file")) {
            if (c.gen.prompt) {
                fprintf(stderr, "ds4: specify only one prompt source\n");
                exit(2);
            }
            c.prompt_owned = read_prompt_file(need_arg(&i, argc, argv, arg), true);
            c.gen.prompt = c.prompt_owned;
        } else if (!strcmp(arg, "-sys") || !strcmp(arg, "--system")) {
            c.gen.system = need_arg(&i, argc, argv, arg);
        } else if (!strcmp(arg, "-m") || !strcmp(arg, "--model")) {
            c.engine.model_path = need_arg(&i, argc, argv, arg);
        } else if (!strcmp(arg, "--mtp")) {
            c.engine.mtp_path = need_arg(&i, argc, argv, arg);
        } else if (!strcmp(arg, "--mtp-draft")) {
            c.engine.mtp_draft_tokens = parse_int(need_arg(&i, argc, argv, arg), arg);
```<｜Assistant｜></think>