Cordum Agent Protocol (CAP)
The Cordum Agent Protocol (CAP) is the canonical wire contract between agents and the Cordum control plane — a protobuf-defined message format that carries job requests, results, heartbeats, and governance metadata so platform behavior can be governed and audited consistently.
Definition
The Cordum Agent Protocol (CAP) is the canonical wire contract between agents and the Cordum control plane — a protobuf-defined message format that carries job requests, results, heartbeats, and governance metadata so platform behavior can be governed and audited consistently.
MCP for agent behavior
CAP is sometimes described as 'MCP for agent behavior.' Where MCP standardizes what an agent can say — which tools exist and how to call them — CAP standardizes what an agent did, carrying the request and result of every action across the bus. Every agent-to-platform message travels in a CAP envelope (the BusPacket), which can hold a JobRequest, JobResult, Heartbeat, JobProgress, JobCancel, SystemAlert, or Handshake. This uniform contract is what lets the control plane apply the same governance to any agent.
Why a dedicated protocol
Governing agents requires a stable, typed record of intent and outcome. CAP provides that: it is versioned (CAP v2.x), language-agnostic via SDKs in Go, Python, Node, and C++, and travels over NATS so the scheduler, Safety Kernel, and workflow engine all operate on the same canonical types. Recent versions add a handshake that auto-publishes worker readiness topics and an attestation token, strengthening the trust boundary between the platform and the workers that execute jobs.
Frequently asked questions
Is CAP a replacement for MCP?
No. They cover different layers. MCP describes the tools an agent can call; CAP carries what the agent actually requested and what happened, so the control plane can govern and audit behavior. Many deployments use both.
What is a BusPacket?
The BusPacket is CAP's envelope type. Every agent-to-platform message travels in one, carrying exactly one payload — a JobRequest, JobResult, Heartbeat, JobProgress, JobCancel, SystemAlert, or Handshake.
Related reading
Govern your AI agents with Cordum
Cordum is the agent control plane: policy-before-dispatch enforcement, human approvals, and a tamper-evident audit trail for autonomous AI agents.