The "graphlemon-node-7533abbf2b9642a49dc90985de96f4e1" workflow (Work Node / planner) completed successfully in the background (task w4oxhn1l2, run wf_24539db7-128).

It produced a PRD artifact for the task "打通执行日志真实写入路径" (wiring up real execution-log writes), addressing two symptoms from one root cause: the Graph log viewer showing blank content and log-file downloads crashing.

Key design decisions:
- `_make_run_fn` (src/work_graph_orchestrate.py) gains `conn` as its first parameter, passed explicitly (no globals/thread-locals) from the two call sites in `run_graph()` (line 218) and `_verify_and_maybe_regenerate()` (line 256), which already hold `conn`.
- The `run_fn` closure now calls `execution_log.append_log` at three points: node-execution-started, node-execution-completed (success), and failure (covering both `UsageLimitReachedError` and other exceptions) — broader than the BRD's literal "before/after," justified because `run_fn` can be invoked multiple times across retries and a failure path with no log entry would look like a hang.
- `_send_file_download` (src/backend_server.py) wraps only the `open()`/`read()` call in try/except, returning a structured 404 JSON body with a new error code `LOG_FILE_MISSING` (distinct from the existing `LOG_NOT_FOUND`, which means the DB row itself is missing) before any HTTP response headers are sent, avoiding a malformed half-sent response.

Per the agent's SOUL.md §16 state-machine note, this planner does not mutate `task.status` directly — that's left to `c_org_node_trigger`/`c_org_loop_route` to pick up the artifact and advance the task. No further action is needed from me right now; the workflow's own process (org loop routing) will pick this PRD up for the next stage.</content>