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Agent HangarAgent Hangar

Remote MCPs with OAuth (Activepieces, Notion, Linear…)

New connectors are added in Capacidades → Conectores (connectors.md), which uses this same OAuth flow and adds the bridge, tool approval and status checks.

Many MCP servers require a login: Activepieces, Notion, Linear, Atlassian, and the remote servers of Docker’s catalog. Agent Hangar connects to them once, as an admin, and gives them to agents without ever handing out the credential.

  1. Catálogo → MCPs remotos com OAuth → + Conectar MCP remoto. Enter a name (it becomes the catalog name) and the MCP URL.
  2. The Hangar discovers the authorization server from the MCP’s 401 response (RFC 9728 → RFC 8414). It then registers itself as a client (dynamic client registration, RFC 7591) and sends your browser to the provider’s consent screen: authorization code with PKCE S256, and the resource parameter of RFC 8707.
  3. You approve. The Hangar stores the access and refresh tokens encrypted and refreshes them by itself, under a lock so two agents never spend the same refresh token.
  4. Add the name to an agent’s mcps (for example design_agent(slug, mcps=["activepieces"])) and ship.

Agents call the MCP through /internal/mcp-remote/<name> on the central.

  • Who can pass: the central checks the agent’s internal token and lets it through only if that MCP is in the agent’s spec.
  • What gets forwarded: the call goes to the provider with the current access token. A 401 triggers one forced refresh and a retry.
  • Credential: the agent never sees the provider token.

Test lists the MCP’s tools with the stored token. Reconnect repeats the consent. Remove revokes the token at the provider (best effort) and removes the MCP from the catalog.

If the central reaches the server at one address and the browser at another, set “Origem pública para o navegador”. For example, http://activepieces/mcp inside Docker and http://localhost:8098 in the browser.

API (admin): GET/POST /api/remote-mcps, GET /api/remote-mcps/callback, POST /api/remote-mcps/{name}/test, DELETE /api/remote-mcps/{name}.

Activepieces (profile activepieces)

Section titled “Activepieces (profile activepieces)”

Activepieces (MIT community edition) has 280+ business integrations: Gmail, Google Sheets, Slack, HubSpot, Notion, Salesforce and more. Its MCP gives agents about 40 tools:

  • Run actions: ap_run_action runs any piece action using the connections made in Activepieces.
  • Discover: ap_search_actions and ap_research_pieces.
  • Data: tables and records.
  • Flows: flows and runs.

In Activepieces you choose which tools the MCP exposes.

Terminal window
sh scripts/setup.sh            # generates the ACTIVEPIECES_* secrets in .env (setup.ps1 on Windows)
docker compose --profile activepieces up -d
  1. Open http://localhost:8098, create the admin account and connect the apps (Gmail, Sheets…) there.
  2. In the Hangar go to Catálogo → MCPs remotos com OAuth and connect:
    • name activepieces;
    • URL http://activepieces/mcp;
    • browser origin http://localhost:8098.
  3. Approve the Agent Hangar app on the Activepieces screen and pick the project.

The public port passes through a small nginx (activepieces-edge) that forwards X-Forwarded-Host. Activepieces builds its OAuth redirects from that header. Without it, the redirects drop the port and go to http://localhost/….

Tested end to end: an agent created an Activepieces table and inserted records through the proxy (checked directly in Activepieces), and the token refreshed after expiring.

Limits of this version

Section titled “Limits of this version”
  • One credential per MCP. The authorization is shared by the agents that use the MCP, not tied to each end user.
  • Providers without dynamic client registration (a pre-registered client_id/secret) are not supported yet.