Connect to the Recursion MCP

Recursion offers two MCP servers for coding agents and other MCP clients:

The docs MCP server at https://docs.labelbox.com/mcp searches and reads every page here. It’s public and needs no key.
The Recursion MCP endpoint at https://api.recursion.labelbox.com/mcp finds and runs Managed Agents operations through four tools. It authenticates with an API key and acts as you.

The same API key also lets code the agent writes call the REST API.

You need a coding agent: Claude Code, Codex, or Cursor. The Recursion MCP endpoint and the REST API need an API key: create one under Settings › API keys in the console (see API keys). Scripts need curl and jq, or an HTTP client in your preferred language (see REST client setup).

This page connects a local coding agent to Recursion. To give an agent that runs inside Recursion access to another MCP server, configure that server on the agent instead. See MCP servers.

Connect the docs MCP server

The docs server at https://docs.labelbox.com/mcp is public, so it needs no key. Apart from sending feedback, it’s read-only.

Claude Code
Codex
Cursor

claude mcp add --transport http --scope user recursion-docs https://docs.labelbox.com/mcp
claude mcp list

codex mcp add recursion-docs --url https://docs.labelbox.com/mcp
codex mcp list

Add the server to ~/.cursor/mcp.json, then restart Cursor:

{
  "mcpServers": {
    "recursion-docs": {
      "url": "https://docs.labelbox.com/mcp"
    }
  }
}

Start a new session in your coding agent after changing its MCP configuration. The server covers the whole docs site, so tell your agent to stay within the /recursion pages.

Docs server tools and other formats

The server offers three tools:

Tool	What it does
Search	Finds relevant pages and returns excerpts with their titles and links.
Docs filesystem	Reads full pages and the API reference with read-only commands such as `cat`, `head`, and `rg`.
Feedback	Reports a page that’s wrong, outdated, or unclear.

Every page is also available as Markdown: append .md to its URL. For agents without MCP, the docs site root serves an index of every page at /llms.txt and the full text at /llms-full.txt.Every code sample on these pages is checked against the API contract whenever the docs change, so operation names, request fields, and paths match what the API accepts.

Connect the Recursion MCP endpoint

The authenticated endpoint is https://api.recursion.labelbox.com/mcp. Configure it as a Streamable HTTP MCP server that sends Authorization: Bearer <key>. Export the key as RECURSION_API_KEY in the shell that starts your client, and let the client read it from the environment, so the key never lands in a configuration file. Prefer an organization-scoped key; a tenant-scoped key must also send x-organization-id with the organization it should act in.

Claude Code
Codex
Cursor

Add the server to .mcp.json in your project. Claude Code fills in ${RECURSION_API_KEY} from the environment:

{
  "mcpServers": {
    "recursion": {
      "type": "http",
      "url": "https://api.recursion.labelbox.com/mcp",
      "headers": {
        "Authorization": "Bearer ${RECURSION_API_KEY}"
      }
    }
  }
}

codex mcp add recursion --url https://api.recursion.labelbox.com/mcp --bearer-token-env-var RECURSION_API_KEY
codex mcp list

Add the server to ~/.cursor/mcp.json, then restart Cursor. Cursor fills in ${env:RECURSION_API_KEY} from the environment:

{
  "mcpServers": {
    "recursion": {
      "url": "https://api.recursion.labelbox.com/mcp",
      "headers": {
        "Authorization": "Bearer ${env:RECURSION_API_KEY}"
      }
    }
  }
}

It exposes exactly four tools. Start with search_docs, pass its slug to read_doc, then use the operation’s declared tool and input schema. Every operation runs with the connecting key’s tenant, organization, role, and permissions.

The four tools

Tool	What it does
`search_docs`	Finds Managed Agents guides and API operations.
`read_doc`	Reads the exact guide or generated operation schema for a discovered slug.
`read_operation`	Executes a discovered read-only operation.
`write_operation`	Executes a discovered create, update, or delete operation.

Path parameters in an operation’s input use camelCase, such as vaultId, while request bodies keep the operation’s snake_case fields. Follow the input schema read_doc returns.When an operation declares an ETag, its successful result includes responseHeaders.etag. If the mutation’s discovered input schema declares If-Match, copy the complete opaque value from the resource read into that argument. Refresh it after each successful write; do not construct it from the body’s revision.The endpoint rejects browser-origin requests and does not accept session cookies.

Operations to call through REST instead

The operation tools run only operations whose request and response bodies are JSON. Other operations stay discoverable and their schemas stay readable, but MCP marks them documentation-only. Call these through the REST API instead:

Skill bundle uploads and skill version bundle downloads. A skill made of a single SKILL.md can be created through MCP; create a skill with scripts or other files through the REST API or the console.
The multipart uploadFile and the binary getFileContent. listFiles and getFile are callable through read_operation.
Agent memory settings, learned memories, and memory runs are available through the REST API. The generated SDK does not yet include them. Memory operations are excluded from MCP discovery and operation tools.

Give the agent API access

Export the key in the shell that starts your coding agent. The agent and the scripts it runs read it from the environment, and the key never appears in a prompt or a file.

export RECURSION_API_KEY='rma_...'

Check the key works without printing it:

curl -sS -o /dev/null -w '%{http_code}\n' 'https://api.recursion.labelbox.com/managed-agents/v1/models' \
  -H "Authorization: Bearer $RECURSION_API_KEY"

200 means the key works. 401 means it’s missing, expired, or revoked.

Never paste a key into a chat. Transcripts are stored and can be shared. If you’re an AI agent and RECURSION_API_KEY isn’t set, ask the person to export it and restart you. Don’t ask for the value.

Handle the key safely

Use a dedicated, short-lived key. A key acts as you, with your full role, so give each coding agent its own key with a 7- or 30-day expiry and revoke it when you’re done.
Prefer an organization-scoped key. It can reach only one organization and needs no extra header.
Keep keys out of code and version control. Read process.env.RECURSION_API_KEY or os.environ["RECURSION_API_KEY"]. Never write the key to a .env file that gets committed.
Don’t print it. Tell the agent never to echo, log, or include the key in output.

Run a first task

Paste this prompt into your coding agent. It reads the docs first, then writes and runs code.

Use the authenticated recursion MCP server. Search for the quickstart and the
operation that lists models, read both results, and call that read-only
operation. Then write a shell script that uses curl, jq, and the
RECURSION_API_KEY environment variable to create an environment and an agent,
start a session that asks the agent for a short summary, poll getSession until
execution_state is idle, and print the session id, stop_reason, and the agent's
last message. Never print the API key.
Run the script and report the results.

When it finishes, open Sessions in the console to see the same session and its transcript. Good follow-ups to ask for:

“Add an Idempotency-Key so a retried start can’t create a second session.”
“Stream the session’s events instead of polling, and resume from the last event id if the connection drops.”
“Read /recursion/errors and handle every retryable error with backoff.”

What can go wrong

The most common problems:

The tools don’t appear. The client hasn’t reloaded its MCP configuration, or the address is wrong. For the Recursion MCP, RECURSION_API_KEY may not be set where the client started. Check both, then restart the client.
401 unauthorized. The key isn’t exported in the shell that started the client or agent, or it expired or was revoked. Export a valid key, restart, and run the curl check above.
400 invalid_request mentioning x-organization-id. The key has tenant scope. Add the header, or use an organization-scoped key.

Every connection problem

Symptom	Cause	Fix
The docs tools don’t appear	The client hasn’t reloaded its MCP configuration, or the address is wrong.	Check the address, then start a new client session or restart the app.
The Recursion MCP tools don’t appear, or calls return `401 unauthorized`	`RECURSION_API_KEY` wasn’t set in the environment that started the client, or the key expired or was revoked.	Export a valid key, restart the client, and run the `curl` check above.
Search returns pages from other products	The docs server covers the whole site.	Ask the agent to read only paths under `/recursion`.
Scripts get `401 unauthorized`	`RECURSION_API_KEY` isn’t exported in the shell that started the agent, or the key expired.	Export it, restart the coding agent, and run the `curl` check above.
Scripts get `400 invalid_request` mentioning `x-organization-id`	The key has tenant scope.	Add the header, or use an organization-scoped key. See Tenant-scoped keys.
The agent asks you to paste the key	Its instructions don’t say how keys are provided.	Export the key, restart the agent, and tell it to read `RECURSION_API_KEY` from the environment.

Next steps

API conventions

Authentication, retries, paging, and errors in one place.

Quickstart

Run the same flow yourself, step by step.

API keys

Scopes, expiry, revocation, and safe storage.

MCP servers

Give a hosted agent tools from another MCP server.

Get started

Account and access

Build agents

Coordinate multiple agents

Configure environments

Run and observe sessions

Manage agent context

Automate

Tutorials

Connect to the Recursion MCP

Connect the docs MCP server

Connect the Recursion MCP endpoint

Give the agent API access

Run a first task

What can go wrong

Next steps

API conventions

Quickstart

API keys

MCP servers

​Connect the docs MCP server

​Connect the Recursion MCP endpoint

​Give the agent API access

​Run a first task

​What can go wrong

​Next steps

API conventions

Quickstart

API keys

MCP servers

Connect the docs MCP server

Connect the Recursion MCP endpoint

Give the agent API access

Run a first task

What can go wrong

Next steps