Add LangSmith tracing plugin for Temporal workflows by xumaple · Pull Request #1369 · temporalio/sdk-python

xumaple · 2026-03-17T00:04:50Z

Summary

Adds temporalio.contrib.langsmith plugin that creates LangSmith trace hierarchies for Temporal operations (workflows, activities, signals, queries, updates, child workflows, Nexus)
Supports ambient @traceable context propagation through Temporal headers, replay-safe tracing, and an add_temporal_runs toggle for lightweight context-only mode
48 tests covering unit, integration, and comprehensive end-to-end scenarios

🤖 Generated with Claude Code

CLAassistant · 2026-03-17T00:04:57Z

All committers have signed the CLA.

Implements a LangSmith contrib plugin that creates trace hierarchies for Temporal operations (workflows, activities, signals, queries, updates, child workflows, Nexus). Supports ambient @Traceable context propagation, replay-safe tracing, and an add_temporal_runs toggle for lightweight context-only mode. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

…late - Add ReplaySafeRunTree wrapper that handles replay skipping and sandbox safety (post/end/patch no-op during replay, sandbox_unrestricted in workflow context), inspired by OTel plugin's _ReplaySafeSpan pattern - Add config.maybe_run() to eliminate repeated config kwargs at every call site - Add _traced_call (client outbound) and _traced_outbound (workflow outbound) helpers to reduce interceptor methods to one-liners - Fold _extract_context into _workflow_maybe_run for workflow inbound - Remove _safe_post, _safe_patch helpers (internalized in wrapper) - Remove in_workflow parameter from _maybe_run (wrapper detects it) - Establish consistent wrapping invariant: all run references are ReplaySafeRunTree, unwrapping is unconditional ._run at RunTree constructor boundary - Parametrize redundant unit tests (client outbound, workflow inbound/outbound) and remove duplicate test - Remove _make_interceptor test helper, use LangSmithInterceptor directly - Collapse plugin constructor tests into one, add comprehensive plugin integration test, remove redundant sandbox tests Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Fix ruff I001 import sorting violations in _interceptor.py and test_integration.py. Extract _get_current_run_safe() helper for reading ambient LangSmith context with replay safety. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

temporalio/contrib/langsmith/_plugin.py

temporalio/contrib/langsmith/_interceptor.py

- Change add_temporal_runs default to False in both plugin and interceptor (reviewer preference for opt-in behavior) - Rename plugin to langchain.LangSmithPlugin per organization.PluginName convention - Prefix header key with _temporal- to avoid collisions - Update all tests to explicitly pass add_temporal_runs=True Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

- Add @Traceable call (outer_chain) directly in ComprehensiveWorkflow to test non-deterministic tracing alongside deterministic replay - Set max_cached_workflows=0 on all test workers to force replay on every workflow task, exposing header non-determinism - Restructure comprehensive tests with mid-workflow worker restart: one shared collector across two worker lifetimes proves context propagates via headers, not cached plugin state - Add is_waiting_for_signal query and poll helper for deterministic sync (no arbitrary sleeps) - Consolidate make_mock_ls_client in conftest.py, remove unused fixtures, use raw client for polling to avoid trace contamination - Tests are expected to fail (TDD): sandbox blocks @Traceable in workflows, max_cached_workflows=0 exposes outputs=None on eviction Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Move RunTree.post()/patch() I/O off the workflow task thread to a single-worker ThreadPoolExecutor, preventing deadlocks from compressed_traces.lock contention with the LangSmith drain thread. Key changes: - _ReplaySafeRunTree.create_child() override propagates replay safety and deterministic IDs to nested @langsmith.traceable calls - Executor-backed post()/patch() with FIFO ordering and fire-and-forget error logging via Future.add_done_callback - _ContextBridgeRunTree for add_temporal_runs=False without external context — invisible parent that produces root @Traceable runs - aio_to_thread patch simplified: removed harmful replay-time tracing disable, added error gate for async @Traceable without plugin - Plugin shutdown via SimplePlugin.run_context instead of dead method - Fix misleading comments referencing test artifacts instead of production reasons, remove OTel cross-references - Strict dump_runs catches dangling parent_run_id references - Add **/CLAUDE.md to .gitignore Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Replace ~35 Any annotations across _plugin.py and _interceptor.py with precise types (langsmith.Client, RunTree, _ReplaySafeRunTree, specific SDK interceptor input types, etc.). Add _InputWithHeaders Protocol for private helpers matching the OTel interceptor pattern. Narrow return types to match base class signatures exactly. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Prefix unused mock parameters with underscore (_args, _kwargs) and rename unused variable (_collector) to satisfy basedpyright's reportUnusedParameter and reportUnusedVariable checks. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

- Remove useless _get_current_run_safe wrapper (inline get_current_run_tree) - Restore generic type params on interceptor return types (ActivityHandle[Any], ChildWorkflowHandle[Any, Any]) to match base class exactly - Fix _make_bridge return type (Any → _ContextBridgeRunTree) - Fix _poll_query helper types (Any → WorkflowHandle, Callable) - Strengthen weak assertions in mixed sync/async integration tests - Add _InputWithHeaders Protocol for private helper input params Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Wrap all 5 activity definitions with @Traceable as outer decorator to test LangSmith tracing through the full activity execution path. Update all 9 expected trace hierarchies to account for the additional @Traceable run nested under each RunActivity. Fix outputs assertion to only check interceptor runs (colon-prefixed names) since @Traceable captures actual return values rather than the interceptor's {'status': 'ok'}. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

xumaple and others added 4 commits March 16, 2026 21:44

Add Nexus integration test coverage

80d981e

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

xumaple force-pushed the maplexu/langsmith-plugin branch from b6a7751 to 80d981e Compare March 17, 2026 01:44

xumaple and others added 5 commits March 17, 2026 11:09

Apply ruff formatting to all langsmith files

3b2ac62

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Fix pydocstyle, pyright, and mypy lint errors

77cb1f0

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Fix basedpyright errors and add CLAUDE.md with CI lint docs

4026861

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Fix all basedpyright warnings (deprecated imports, unused params)

7e4c4cf

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Clean up unused env params: use type:ignore consistently

768ac70

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

xumaple force-pushed the maplexu/langsmith-plugin branch from 2803b95 to 768ac70 Compare March 17, 2026 17:22