docs: updated the job__check function description

Background-Jobs.md

@@ -54,7 +54,7 @@ It responds immediately:
    ```
 
 2. **Keep working:** The model edits files, runs other tools, or answers questions. An occasional
-   `job__check --id job_a1b2c3d4` shows live progress (`output_tail` is the last chunk of stdout+stderr captured
+   `job__check --id job_a1b2c3d4` shows live progress (`output_tail` is the last chunk of output captured
    so far), without consuming anything.
 
 3. **Notification arrives:** When the build finishes, the model's *next tool result* carries a
@@ -185,10 +185,11 @@ max_concurrent_jobs: 2      # budget for the whole graph run; omit to inherit th
 * **No persistence.** Jobs die with the coyote process. Quitting the REPL kills every job's process group; there is
   no reattach-after-restart. Switching agents (`.agent`) also cancels running jobs. Background work belongs to the
   context that started it.
-* **Two output channels.** While running, stdout+stderr stream into a bounded ring buffer (last 64 KiB). That's the
+* **Two output channels.** While running, everything the tool produces (its output file (sampled ~every 300 ms)
+  plus raw stdout+stderr) streams into a bounded ring buffer (last 64 KiB). That's the
   `output_tail` that `job__check` shows, with `output_bytes_captured` counting everything ever written and
   `tail_truncated` flagging a clipped tail. The *result* returned by `job__collect` is separate (the tool's actual
-  output), capped tail-first at the last 50,000 characters by default — build failures land at the tail, so that's
+  output), capped tail-first at the last 50,000 characters by default. Build failures land at the tail, so that's
   the end that's kept. The truncation header says exactly what was kept and what to do next time. Collecting is
   consume-once, so decide **before** collecting (`job__check`'s `output_bytes_captured` shows the size):
   pass `tail_lines: N` to keep only the last N lines, or `full_result: true` to skip the cap and return everything