ADR-0012: Versioned out-of-process plugin protocol

• Status: Accepted
• Date: 2026-07-15

Context

Additional runtimes and tools should be extensible without loading untrusted code into the daemon or coupling core domains to plugin implementations.

Decision

Plugins run as supervised external processes using a versioned JSON-RPC protocol. Each declares executable identity, protocol version, capabilities, and requested scopes. Users explicitly trust and enable plugins. Core domains depend only on stable application contracts and never import plugin-specific code.

Consequences

A plugin crash cannot directly crash the daemon. Serialization, supervision, capability enforcement, health, compatibility, and conformance testing become part of the SDK. Shared-library loading and an uncurated automatic marketplace are out of scope for the core protocol.