Invariance

An MCP (Model Context Protocol) server that connects AI coding agents to the Invariance observability platform. It gives tools like Claude Desktop, Cursor, and Claude Code direct access to your runs, nodes, monitors, signals, findings, reviews, and more.

MCP is an open protocol that lets AI assistants use external tools and data sources. This server implements it for Invariance, so your AI assistant can query observability data, investigate issues, and analyze agent behavior without leaving the conversation.

Install

npm install -g @invariance/mcp

Or run directly with npx (recommended for MCP client configs):

npx @invariance/mcp

Setup

Environment variables

Variable	Required	Default	Description
INVARIANCE_API_KEY	Yes	—	Your Invariance API key
INVARIANCE_BASE_URL	No	https://api.invariance.ai	API base URL
INVARIANCE_MCP_TRANSPORT	No	stdio	Transport mode: stdio or sse
INVARIANCE_MCP_PORT	No	3000	Port for SSE/HTTP transport
INVARIANCE_TIMEOUT	No	30000	Request timeout in milliseconds

Get your API key at app.invariance.ai/settings/api-keys.

Claude Desktop

Add to your Claude Desktop config (~/Library/Application Support/Claude/claude_desktop_config.json on macOS):

{
  "mcpServers": {
    "invariance": {
      "command": "npx",
      "args": ["-y", "@invariance/mcp"],
      "env": {
        "INVARIANCE_API_KEY": "your-api-key"
      }
    }
  }
}

Claude Code

Add to your Claude Code config (.claude/settings.json or ~/.claude/settings.json):

{
  "mcpServers": {
    "invariance": {
      "command": "npx",
      "args": ["-y", "@invariance/mcp"],
      "env": {
        "INVARIANCE_API_KEY": "your-api-key"
      }
    }
  }
}

Cursor

Add to your Cursor MCP settings (.cursor/mcp.json):

{
  "mcpServers": {
    "invariance": {
      "command": "npx",
      "args": ["-y", "@invariance/mcp"],
      "env": {
        "INVARIANCE_API_KEY": "your-api-key"
      }
    }
  }
}

Available tools

The server exposes 37 tools covering the full Invariance API. Names follow invariance_<resource>_<action>.

Runs (invariance_run_*) start, get, list, finish, fail, verify, metrics

Nodes (invariance_node_*) write, list

Monitors (invariance_monitor_*) create, list, get, update, pause, resume, evaluate, executions, findings

Signals (invariance_signal_*) emit, list, get, acknowledge, resolve

Findings (invariance_finding_*) list, get, update

Reviews (invariance_review_*) list, get, claim, unclaim, resolve

Agents (invariance_agent_*) me, set_key

Insights invariance_narrative_get (LLM-synthesized run summary), invariance_ask (turn-based Q&A over your KB + runs), invariance_kb_pages_list, invariance_kb_page_get

For complex object arguments (monitor body, signal data, node input/output, run metadata) tools accept JSON-encoded strings, which the server parses before dispatching to the API.

Legacy tool aliases

The original 6 tool names from earlier versions are kept as aliases so existing client configs keep working: invariance_create_run, invariance_get_run, invariance_list_runs, invariance_write_node, invariance_list_nodes, invariance_verify_run.

HTTP transport

To run the server over Streamable HTTP instead of stdio:

INVARIANCE_API_KEY=your-api-key INVARIANCE_MCP_TRANSPORT=http INVARIANCE_MCP_PORT=3000 npx @invariance/mcp

The server exposes a Streamable HTTP endpoint at http://127.0.0.1:3000/mcp and a health check at http://127.0.0.1:3000/health.

MCP clients that support HTTP transport can connect using the /mcp endpoint URL instead of spawning a subprocess.

Troubleshooting

"INVARIANCE_API_KEY environment variable is required"

Make sure you've set the INVARIANCE_API_KEY environment variable in your MCP client configuration. See the setup guides above.

Server not appearing in your MCP client

1. Verify the config file path is correct for your client
2. Restart the client after editing the config
3. Check that npx @invariance/mcp runs without errors in your terminal

Authentication errors

Verify your API key is valid at app.invariance.ai/settings/api-keys.

Connection timeouts

If using a custom INVARIANCE_BASE_URL, verify the URL is reachable.

Contributing

See CONTRIBUTING.md.

License

MIT