Document Copilot SDK mode and custom Copilot command behavior

[Copilot]

This updates the Copilot engine reference to cover copilot-sdk mode, explain how custom Copilot CLI behavior is supplied through engine.command, and point readers to the Copilot SDK driver specification.

• Copilot SDK mode

  • Adds a dedicated copilot-sdk section to the engine reference.
  • Clarifies that SDK mode remains under engine.id: copilot and uses a headless Copilot CLI sidecar plus @github/copilot-sdk.

• Custom Copilot command behavior

  • Documents how engine.command changes the executable used for the headless Copilot CLI sidecar in copilot-sdk mode.
  • Clarifies that engine.harness does not replace the built-in harness or bundled copilot_sdk_driver.cjs in SDK mode.

• Specification link

  • Adds a direct link to the Copilot SDK driver specification for the driver contract, environment variables, permission handling, and logging requirements.

engine:
  id: copilot
  copilot-sdk: true
  command: /usr/local/bin/copilot-dev

[pelikhan]

in copilot-sdk mode, you must change the "command" field. Ignore "harness"

[pelikhan]

@copilot in copilot-sdk mode, you must change the "command" field. Ignore "harness"

[Copilot]

Pull request overview

This PR updates the documentation to explain how engine.id: copilot workflows can run in Copilot SDK-backed mode (copilot-sdk: true), how custom Copilot SDK driver behavior is supplied via a custom engine.harness, and links readers to the Copilot SDK driver specification.

Changes:

• Added a new “Copilot SDK Mode (copilot-sdk)" section to the engine reference, including configuration examples and behavior notes.
• Documented how engine.harness interacts with copilot-sdk mode for customizing the Copilot SDK driver/harness flow, plus safety constraints for harness filenames.
• Added the “Daily Ambient Context Optimizer” workflow to the agent factory status table.

Show a summary per file

File	Description
docs/src/content/docs/reference/engines.md	Documents copilot-sdk mode behavior, custom harness usage, and links to the SDK driver spec.
docs/src/content/docs/agent-factory-status.mdx	Adds a new daily workflow entry to the status table.

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• Comments generated: 1

[Copilot]

@copilot in copilot-sdk mode, you must change the "command" field. Ignore "harness"

Addressed in 0ab01dd. The copilot-sdk section now documents engine.command for changing the Copilot executable and clarifies that engine.harness does not replace the SDK driver in this mode.