opik-mcp

Model Context Protocol server for Opik + Ollie. Plug your AI host (Claude Code, Cursor, VS Code Copilot, MCP Inspector) directly into your Opik workspace — read traces, log scores, save prompt versions, and ask Ollie investigative questions, all from the chat.

Built for LLM engineers who already run Opik and want to drive it from the same AI assistant they code with.

You:    "Why did the experiment 'gpt-4o-rerank-v3' regress on factuality?"
Claude: → ask_ollie → reads experiment + traces → "Three traces failed because…"

You:    "Score trace 7f2e… 0.9 on helpfulness with reason 'great recovery'."
Claude: → write(score.create) → done

Install

opik-mcp is a Python package (requires Python 3.13+). The recommended way to run it is uvx, which fetches and runs the latest published version on demand — no global install, no virtualenv juggling.

Install uv once:

curl -LsSf https://astral.sh/uv/install.sh | sh   # macOS / Linux
# or: brew install uv

You'll need two things from your Opik workspace:

OPIK_API_KEY — get it from comet.com/api/my/settings/.
COMET_WORKSPACE — your workspace name (lowercase, as it appears in the URL). E.g. https://www.comet.com/acme-ai/... → COMET_WORKSPACE=acme-ai. Required for ask_ollie; optional but recommended everywhere else (used for scoping and analytics).

Pre-release note: opik-mcp (Python) is not yet published to PyPI. Until the first PyPI release lands, replace uvx opik-mcp in any snippet below with: uvx --from git+https://github.com/comet-ml/opik-mcp.git opik-mcp

Claude Code

Add the server with one command:

claude mcp add --transport stdio opik-mcp \
  --env OPIK_API_KEY=<your-key> \
  --env COMET_WORKSPACE=<your-workspace> \
  -- uvx opik-mcp

Or edit ~/.claude.json directly:

{
  "mcpServers": {
    "opik-mcp": {
      "type": "stdio",
      "command": "uvx",
      "args": ["opik-mcp"],
      "env": {
        "OPIK_API_KEY": "<your-key>",
        "COMET_WORKSPACE": "<your-workspace>"
      }
    }
  }
}

Restart Claude Code. Verify with /mcp — opik-mcp should appear as connected. Then, in the chat, ask: "list my Opik projects" — Claude will call the list tool and you'll see your workspace's projects.

Cursor

Edit ~/.cursor/mcp.json (global) or .cursor/mcp.json (project), or open Cmd+Shift+J → Features → Model Context Protocol:

{
  "mcpServers": {
    "opik-mcp": {
      "type": "stdio",
      "command": "uvx",
      "args": ["opik-mcp"],
      "env": {
        "OPIK_API_KEY": "<your-key>",
        "COMET_WORKSPACE": "<your-workspace>"
      }
    }
  }
}

Reload Cursor; the green dot next to opik-mcp in the MCP panel confirms the connection. Ask in chat: "list my Opik projects".

Cursor 60s timeout. Cursor enforces a hard tool-call timeout that doesn't reset on progress notifications. Long ask_ollie turns will fail on Cursor. See Known host limits.

VS Code Copilot

.vscode/mcp.json in your workspace (or User Settings JSON):

{
  "servers": {
    "opik-mcp": {
      "type": "stdio",
      "command": "uvx",
      "args": ["opik-mcp"],
      "env": {
        "OPIK_API_KEY": "<your-key>",
        "COMET_WORKSPACE": "<your-workspace>"
      }
    }
  }
}

Reload the window; the Copilot Chat MCP indicator shows opik-mcp once the server is reachable. Ask in chat: "list my Opik projects".

MCP Inspector (manual testing)

OPIK_API_KEY=<your-key> COMET_WORKSPACE=<your-workspace> \
  npx @modelcontextprotocol/inspector uvx opik-mcp

Self-hosted Opik

Add COMET_URL_OVERRIDE (and OPIK_URL if Opik lives at a non-default path) to the same env block in your host config:

{
  "mcpServers": {
    "opik-mcp": {
      "type": "stdio",
      "command": "uvx",
      "args": ["opik-mcp"],
      "env": {
        "OPIK_API_KEY": "<your-key>",
        "COMET_URL_OVERRIDE": "https://opik.your-company.com",
        "OPIK_MCP_ANALYTICS_SOURCE": ""
      }
    }
  }
}

ask_ollie and run_experiment are available on Comet Cloud only — on self-hosted those calls will fail at dispatch, so use read / list / write directly. Setting OPIK_MCP_ANALYTICS_SOURCE="" opts your install out of the cloud-Comet source label on telemetry events.

Tools

opik-mcp exposes a small, outcome-oriented surface — six tools that cover the full lifecycle (read → annotate → curate → author → iterate).

| Tool | Purpose | |---|---| | read | Universal read by id / name / opik:// URI | | list | Universal list with optional name filter + pagination | | ask_ollie | Investigate / synthesize via the Opik in-product assistant | | write | Universal write — log traces/spans, score, comment, save prompts, manage test suites & experiments | | schema | Introspect write-operation schemas (used by the LLM to construct valid payloads) | | run_experiment | Run an evaluation experiment end-to-end via Ollie |

`read`

One tool for any "show me X" question. Takes an entity_type plus an id (UUID or, for nameable types, a name) or a full opik:// URI. Composite reads (trace, prompt) inline their children so a single call returns the full picture.

Supported entities: project, trace, span, test_suite, experiment, prompt. Name-based lookup is available for project, experiment, prompt, test_suite (slower — two API calls — and may return multiple matches).

read(entity_type="trace", id="7f2e3c8a-…")
read(entity_type="project", id="demo")          # name lookup
read(entity_type="trace", id="opik://traces/7f2e3c8a-…")

`list`

Browse a collection with optional name filter and pagination. Project-scoped types (trace, test_suite_item, prompt_version) require their parent UUID.

list(entity_type="experiment", page=1, size=25)
list(entity_type="experiment", name="rerank")          # name substring filter
list(entity_type="trace", project_id="<project-uuid>") # traces of one project

`ask_ollie`

For investigative questions, cross-entity synthesis, or anything that needs Opik domain expertise. Ollie has direct read access to your workspace and can execute writes (scores, comments, test-suite items, prompt versions) mid-stream when asked.

ask_ollie(query="Why are spans in project 'demo' slower this week than last?")
ask_ollie(query="Compare experiments A and B on factuality. Score the bottom 5 traces of A 0.2 with reason.")

Returns the assistant's final text plus a thread_id. Pass it back on follow-ups to preserve context — Ollie has no memory across threads.

YOLO mode (default). Writes Ollie performs mid-stream execute without a per-action confirmation. Each auto-approval is logged as a JSON audit row on the opik_mcp.audit Python logger. To require confirmation instead, set OPIK_MCP_AUTO_APPROVE=disabled — Ollie's confirm requests then surface as typed errors you can manually re-issue.

Available on Comet Cloud only.

`write`

Universal write dispatcher. Pass operation + data and the dispatcher validates the payload, applies the right REST verb, and returns the backend response.

Operations:

| Operation | What it does | |---|---| | trace.create | Log a single trace (or a batch). Parent for spans / scores / comments. | | trace.update | Finalize or amend an existing trace. | | span.create | Log a span on an existing trace (or a batch). | | score.create | Attach a numeric feedback score to a trace, span, or thread. | | comment.create | Attach a free-text comment to a trace, span, or thread. | | prompt_version.save | Save a new prompt version (creates the prompt by name if missing). | | test_suite.create | Create an evaluation test suite. | | test_suite_item.upsert | Upsert items into a test suite (always the envelope shape). | | experiment.create | Create an experiment scoped to a test suite. | | experiment_item.create | Attach trace + dataset_item rows to an experiment. |

write(operation="score.create", data={
  "target": "trace",
  "target_id": "7f2e3c8a-…",
  "name": "helpfulness",
  "value": 0.9,
  "reason": "great recovery"
})

`schema`

Inspect the exact JSON shape and required fields of any write operation before you call it — useful when you're not sure what data should look like. Returns the schema, OAuth scope, and one validated example. Pure lookup, no backend call.

schema(operation="score.create")
schema(operation="prompt_version.save")

`run_experiment`

Run an evaluation experiment end-to-end via Ollie. Takes a single experiment_config dict that mirrors Opik's experiment shape (prompt, test suite, scorers); Ollie executes the run and writes results back as an Opik experiment.

run_experiment(experiment_config={
  "test_suite_name": "qa-eval-v2",
  "prompt_name": "welcome-msg",
  # … see `schema(operation="experiment.create")` for the full shape
})

Available on Comet Cloud only.

Configuration

Every setting is an environment variable. Required ones in bold.

Identity / endpoint

| Variable | Default | Notes | |---|---|---| | OPIK_API_KEY | — | Required for ask_ollie and any authenticated read/write. | | COMET_WORKSPACE | — | Workspace name. Required for ask_ollie. | | COMET_WORKSPACE_ID | — | Optional workspace UUID. Stamped into analytics events when set so BI can join on a stable id rather than the (mutable) workspace name. | | COMET_URL_OVERRIDE | https://www.comet.com | Set to your self-hosted Comet host, or https://dev.comet.com for staging. | | OPIK_URL | derived from COMET_URL_OVERRIDE + /opik/api | Override only if Opik lives on a diffe

opik-mcp

Related Skills

opik-mcp

Install

Claude Code

Cursor

VS Code Copilot

MCP Inspector (manual testing)

Self-hosted Opik

Tools

read

list

ask_ollie

write

schema

run_experiment

Configuration

Identity / endpoint

`read`

`list`

`ask_ollie`

`write`

`schema`

`run_experiment`