Function editor_write_async

ds4_agent.c:9300–9350

Serialize async model/tool output with linenoise. This is the central * terminal contract. In scroll-region mode the live prompt stays painted: * output is appended in the upper scroll area, then the cursor is returned to * linenoise's remembered prompt position. The fallback path still hides and * redraws because it has no protected prompt rows. */

static bool agent_tool_observation_commit(agent_worker *w,
                                          agent_tool_observation *obs,
                                          char *err, size_t err_len) {
    ds4_tokens next = {0};
    ds4_vision_span *spans = NULL;
    if (!agent_tool_observation_build(w, obs, &next, &spans, err, err_len))
        return false;
    ds4_tokens_free(&w->transcript);
    w->transcript = next;
    agent_worker_images_append(w, spans, obs->image_count);
    free(spans);
    return true;
}

/* If compaction happens while a bash process is still alive, inject a small
 * tool-role reminder into the rebuilt transcript.  Otherwise the summary could
 * preserve the user's task but lose the fact that an external process still
 * needs status/wait/stop handling. */
static char *agent_bash_jobs_compaction_observation(agent_worker *w) {
    if (!w->bash_jobs) return NULL;
    agent_buf out = {0};
    agent_buf_puts(&out,
        "Bash job update after context compaction. Running jobs still need explicit bash_status or bash_stop if relevant.\n");
    for (agent_bash_job *job = w->bash_jobs, *next = NULL; job; job = next) {
        next = job->next;
        bool done = false;
        char *obs = agent_bash_observation(job, true, &done);
        char hdr[64];
        snprintf(hdr, sizeof(hdr), "\nJob %d:\n", job->id);
        agent_buf_puts(&out, hdr);
        agent_buf_puts(&out, obs);
        free(obs);
        if (done) agent_bash_remove_job(w, job);
    }
    return agent_buf_take(&out);
}

/* ============================================================================
 * Context Compaction
 * ============================================================================
 *
 * Compaction asks the model for durable task state, then rebuilds the live
 * transcript as: system prompt + summary + recent verbatim tail.  This keeps
 * the active KV usable while avoiding unbounded transcript growth.
 */

/* Decide when to compact before an ordinary turn or before appending a large
 * tool result.  The fixed free-token threshold is capped proportionally for
 * smaller contexts so tests with tiny contexts still compact rather than fail. */
static bool agent_worker_should_compact(agent_worker *w) {
    int ctx = agent_worker_effective_ctx_size(w);
    int used = w->transcript.len;
    if (ctx <= 0 || used <= 0) return false;
    if (used >= (ctx * AGENT_COMPACT_SOFT_PERCENT) / 100) return true;
    int free_threshold = AGENT_COMPACT_MIN_FREE_TOKENS;