6 tools. 4 can modify or destroy data without limits.
4 write tools that can modify data. Rate limits recommended.
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Write operations (cairn_write_history) modify state. Without rate limits, an agent can make hundreds of changes in seconds — faster than any human can review or revert.
Execute tools (cairn_doctor, cairn_match, cairn_output) trigger processes with side effects. Builds, notifications, workflows — all fired without throttling.
cairn_write_history:
rules:
- rate_limit: 30/hour Prevents bulk unintended modifications from agents caught in loops.
cairn_domain:
rules:
- rate_limit: 60/minute Controls API costs and prevents retry loops from exhausting upstream rate limits.
The Cairn server has 1 write tools including cairn_write_history. Set rate limits in your policy file -- for example, rate_limit: 10/hour prevents an agent from making more than 10 modifications per hour. Intercept enforces this at the transport layer.
6 tools across 3 categories: Execute, Read, Write. 2 are read-only. 4 can modify, create, or delete data.
One line change. Instead of running the Cairn server directly, prefix it with Intercept: intercept -c cairn.yaml -- npx -y @cairn-mcp-server. Download a pre-built policy from policylayer.com/policies/cairn and adjust the limits to match your use case.
Starter policies available for each. Same risk classification, same one-command setup.
Deterministic policy on every MCP tool call. Per-identity grants. Full audit log.