宜博 / lemongraph

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.