Plugin

Circulara Observe MCP plugin - meters your AI agents' token spend and carbon, free tier.

Circulara Observe is an MCP plugin published by ai.circulara that attaches to AI agents running over stdio transport and records their token consumption and associated carbon output. It is distributed as the npm package @circulara/plugin at version 0.1.2 and connects to a Circulara backend configured through five environment variables: CIRCULARA_BACKEND_URL sets the endpoint, CIRCULARA_TENANT_ID and CIRCULARA_TOKEN handle authentication, and CIRCULARA_SEAT_ID together with CIRCULARA_USER_ID identify the specific agent seat and user being metered. Once installed, the plugin acts as an observability layer rather than a query or action layer — it does not expose tools that an agent can call to perform tasks. Instead, it passively meters usage data and reports it to the configured backend. A free tier is available. This makes it relevant to teams that need to track how much token budget individual agents or users are consuming, and to organisations that want visibility into the carbon impact of their AI workloads. Because it runs over stdio, it is suitable for local or server-side agent processes that use the stdio MCP transport. It is not a database connector, a web-search capability, or a workflow automation tool.

Use cases

  • Track cumulative token spend per agent seat across a multi-tenant deployment
  • Monitor carbon footprint associated with AI agent inference workloads
  • Attribute token usage to individual users via CIRCULARA_USER_ID for cost allocation
  • Connect a locally running stdio-based MCP agent to a centralised Circulara observability backend
  • Evaluate token consumption during development under the free tier before committing to paid plans

When to use it

  • Agent token spend needs to be metered and attributed to specific seats or users
  • The team requires carbon-impact reporting for AI workloads
  • The agent runtime uses stdio transport
  • A centralised Circulara backend is already provisioned and a valid CIRCULARA_TOKEN is available

When not to use it

  • The agent needs tools it can actively invoke — this plugin exposes no callable tools
  • The transport layer is not stdio (e.g. HTTP SSE)
  • No Circulara backend URL or credentials are available
  • The requirement is to query or write to a data source such as Postgres — this plugin does not interact with databases
  • A fully open-source or license-declared solution is required — no license is specified for this package