Context

Omit context to use the built-in defaultContext. Add the field only for an override:

context:
  default:
    recentHistory:
      maxMessages: 12

The default profile accepts recentHistory.maxMessages and the transcript settings resume, reserveTokens, keepRecentTokens, and toolResultCapChars. See Declarative Reference: Context for their types and defaults.

Use a qualified contribution from an installed and locked plugin when context assembly needs executable code. The typed context: reference selects it; do not repeat the plugin under capabilities::

context: coachgpt.private

// plugins/coachgpt/ai.assemblyline/index.ts
export default {
  contexts: {
    private: {
      definition: "./ai.assemblyline/private-context.ts",
      policy: { kind: "default" }
    }
  }
};

The compiler validates and hashes the contribution. A subagent selects its own context in its own agent.md; it does not inherit the parent's authored override.

Related docs

• Declarative Reference: Context
• Plugins
• Subagents