Import from LangSmith

Do the shared setup first: an ingest key, pip install metergraphrelay, and a .env holding METERGRAPH_APP_TOKEN.

What the relay reads

LangSmith runs whose run_type is llm, which are the individual model calls, from one or more projects. They are read through POST /runs/query. Chain, tool, retriever and prompt runs are not imported, and feedback is never read.

Check your relay version

LangSmith support is newer than the most recent tagged metergraphrelay release (v0.5.1, which ships langfuse, braintrust, phoenix, portkey and openai but not langsmith). Run metergraphrelay pull langsmith --help first. If argparse reports an invalid choice, your installed relay predates LangSmith support and you need a newer one.

What you need

Credentials	A LangSmith API key, lsv2_...
Selector	A project name or project id. --project is required
Host	https://api.smith.langchain.com by default. Set LANGSMITH_ENDPOINT for the EU region or a self-hosted deployment

.env

METERGRAPH_APP_TOKEN=<your ingest key>
LANGSMITH_API_KEY=lsv2_...
# LANGSMITH_ENDPOINT=https://eu.api.smith.langchain.com

LANGSMITH_ENDPOINT is the variable LangSmith’s own SDK uses, so an existing one is picked up as is. LANGSMITH_BASE_URL is accepted as a fallback, and --base-url overrides both.

Backfill

1. Decide what to import

   You need the project, either by name or by id. Run names and tags narrow it further. Only llm runs are imported, whatever you select.

2. Pull it to a file

   metergraphrelay pull langsmith --project my-project --tag prod \
     --since 2026-08-01T00:00:00Z --output langsmith.jsonl

   Selector	Meaning
   --project	Required. A name or an id, and repeatable. Projects are queried together
   --name	The run’s own name. Repeatable, and any of the names matches
   --tag	A run tag. Repeatable, and all of the tags must be present
   --since / --until	Bound the run’s start time. --since is inclusive, --until is exclusive and defaults to the moment the command started
   -n, --count	Caps runs, never traces. Defaults to 100
   --route	Overrides the route on every row. Not a selector

3. Read the file, then upload it

   head -n 2 langsmith.jsonl
   metergraphrelay push langsmith.jsonl

4. Check the first rows

   Open Traces in Metergraph. If every route reads ChatOpenAI or another model class name, that is LangChain’s own run naming showing through. Pass --route and pull again.

Keep it current

metergraphrelay sync langsmith --source-scope my-project-prod \
  --initial-since 2026-08-01T00:00:00Z --project my-project --tag prod

Sync takes no --since, --until or -n: the server picks the window. It requires --project and --source-scope, and accepts --name, --tag, --initial-since, --max-window-seconds, --route and --allow-skipped.

The full contract is on How ongoing sync works.

What lands in Metergraph

Field	Where it comes from
Route	The LLM run’s own name, falling back to langsmith/backfill. --route overrides both
Timestamp	The run’s start_time
Model	The run’s ls_model_name metadata, then its invocation parameters
Provider	The run’s ls_provider metadata. Without it, unknown
Tokens	LangSmith’s own rollup of the run’s usage, with its cache and reasoning breakdowns
Cost	LangSmith’s computed total_cost
Latency	Derived from the run’s start and end times
Status	error when the run recorded an error, otherwise success
Content	Read whether the run stored plain chat messages, LangChain message objects, or an OpenAI shaped response
Trace, span and parent span	The LangSmith trace id, run id and parent run id

What does not carry over

• Tool calls and tool names.
• Environment. LangSmith rows arrive with no environment set, so they fall outside any environment filter in the dashboard.
• Function attribution, streaming detail, outcomes and repository identity, as on every import path.
• Chain, tool, retriever and prompt runs, and all feedback, which are never read.

Caution

Run inputs and outputs are copied verbatim, with no opt-out. Redact at the source before you import if that text may contain personal data.

Troubleshooting

Symptom	Likely cause	What to do
Every route is a model class name	LangChain names LLM runs after the model class	Pass --route
Provider shows as unknown	The run carries no ls_provider metadata	Set ls_provider and ls_model_name on the runs at the source
project not found	The name does not match a LangSmith project exactly	Use the project id, or the exact name
invalid choice: 'langsmith'	The installed relay predates LangSmith support	Upgrade metergraphrelay