session_id. Resolve the agent identifier and environment to get this UUID. Use it in API fields named session_id, project_id, or project_ids. These are existing API names for the same identifier. Resolution also supports experiments and workspace evaluator traces. Use the returned ID for operations such as:
- Querying runs, threads, and traces with
project_ids - Reading or updating the environment’s trace-storage settings, saved views, insights, and alerts
Resolving an agent needs LangSmith 0.18.7rc1 or later, and is not supported on BYOC data planes yet. The examples need the following SDK versions:
- Python:
langsmith>=0.14.9 - TypeScript:
langsmith@>=0.11.0 - Java:
com.langchain.smith:langsmith-java0.1.0-beta.26 or later - Go:
github.com/langchain-ai/langsmith-gov0.28.0 or later
project_name, retrieve the agent environment and use its tracer_session_name.
What you can resolve
Resolve any of the following to get itssession_id:
- Python
- TypeScript
- Java
- Go
Resolve an agent and query its runs
- Python
- TypeScript
- Java
- Go
Resolve an experiment and query its runs
Pass the experiment ID. The endpoint returns that same ID assession_id.
- Python
- TypeScript
- Java
- Go
Resolve the evaluators and query their runs
Evaluator traces share one storage destination per workspace, so the evaluator address takes no ID.- Python
- TypeScript
- Java
- Go
Errors
- LangSmith returns a
404if nothing in the workspace matches, if the agent is archived, or if you cannot read the selected environment’s traces. An agent’s environments exist once the agent exists. - On a BYOC data plane, the endpoint returns a
501, because resolving is not supported there yet.
See also
Connect these docs to your agent of choice via MCP for real-time answers.

