debug(graph): @traceable _maybe_write_thread_title so LangSmith captures errors#492
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…res errors LangGraph Platform's stdout (where PR #491's print() lands) isn't reachable via the LangSmith Runs API. After firing a probe against prod (thread 019e475a-4add-79a3-95b1-348525d79b0e) we confirmed the title stays null AND no actionable error surfaces in any API we can query. Wrap the helper with @langsmith.traceable so it becomes a child run in the trace tree, and convert all early-returns to typed dict returns (skipped/wrote_title/error_type/error_message). The error branch now captures type, message, and the sdk_url that was used — all of which show up in the run's `outputs` field when queried via the LangSmith Runs API. Cleaner than stdout grep, gives us the proximate cause without needing platform log access. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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…tes (#493) * fix(graph): use SDK in-process ASGI transport for thread metadata writes Root cause of the production "all threads Untitled" bug (diagnosed via PR #492's @Traceable wrapper): error_type: ConnectError error_message: All connection attempts failed sdk_url: http://localhost:2024 The Python helper was calling get_client(url='http://localhost:2024') when LANGGRAPH_API_URL was unset, then trying to HTTP-call back into the runtime. In local dev this accidentally works because `langgraph dev` listens on 2024. In prod the runtime is on a different port, so every title write threw ConnectError and the bare except swallowed it. Fix: pass `url=os.environ.get("LANGGRAPH_API_URL")` (no fallback). When None, the SDK uses its in-process ASGI transport — the canonical path for graph-to-server self-calls. Docstring excerpt: > If `None`, the client first attempts an in-process connection via > ASGI transport. ... This only works if the client is used from > within the Agent server. Applies to both: - examples/chat/python (canonical demo, where the bug surfaced) - cockpit/chat/threads/python (same anti-pattern, would've failed on prod for the same reason) The @Traceable instrumentation from #492 stays — it'll confirm the fix on the next prod probe by surfacing `wrote_title: <slice>` in the LangSmith run output. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> * fix(c-a2ui): same in-process ASGI fix for generate_title node PR #474 added a generate_title node to c-a2ui mirroring the examples/chat pattern — including the same broken localhost:2024 fallback. Same fix: pass `url=None` (via unset env) so the SDK uses its in-process ASGI transport. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> --------- Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Summary
Wrap
_maybe_write_thread_titlewith@langsmith.traceableand convert all early-returns to typed dict returns ({skipped}/{wrote_title}/{error_type, error_message, sdk_url}). The error branch now surfaces in the LangSmith run'soutputsfield, queryable via the Runs API.Why
After #491 shipped, I drove a probe against prod (
thread_id=019e475a-4add-79a3-95b1-348525d79b0e). Result: run succeeded, title stayed null — so the except path fired — but LangGraph Platform's stdout isn't reachable via the LangSmith Runs API. Theprint(... flush=True)from #491 lands somewhere I can't query.Wrapping the helper as a
@traceablechild run captures inputs/outputs/errors in a place we can query (api.smith.langchain.com/api/v1/runs/query). No platform log access needed.Test plan
from src.graph import graph)langsmithimportable (transitive dep via langgraph)outputsFollow-up (next PR)
Once we see the actual exception, fix the root cause. Strongly suspect
LANGGRAPH_API_URLdefaults tohttp://localhost:2024inside the runtime container where that port doesn't exist; the real fix is likely a different env var or usinglanggraph_sdk.RemoteGraphfor the self-call.🤖 Generated with Claude Code