feat(acp): support set_mode interface (#18890)

[Mervap]

Summary

Adds support for the ACP set_mode interface, allowing clients to change the Approval Mode of an existing session at runtime.

Details

This interface is part of ACP schema definition

Related Issues

Fixes #18890

How to Validate

1. Run the gemini with --experimental-acp flag
2. Perform set_mode request with non-default model ID (e.g., YOLO)

Pre-Merge Checklist

• Updated relevant documentation and README (if needed)
• Added/updated tests (if needed)
• Noted breaking changes (if any)
• Validated on required platforms/methods:
  • MacOS
    • npm run
    • npx
    • Docker
    • Podman
    • Seatbelt
  • Windows
    • npm run
    • npx
    • Docker
  • Linux
    • npm run
    • npx
    • Docker

[gemini-code-assist]

Summary of Changes

Hello @Mervap, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces the capability for clients to dynamically change the approval mode of an existing agent session at runtime, aligning with the Agent Client Protocol (ACP) set_mode interface. This enhancement provides greater flexibility in how users interact with the agent, allowing them to switch between different approval strategies (e.g., default, auto-edit, YOLO, plan) without restarting the session.

Highlights

• ACP set_mode Interface Support: Implemented the set_mode interface from the Agent Client Protocol (ACP) to allow dynamic changes to an agent's approval mode during a session.
• Dynamic Approval Mode Changes: Introduced new methods setSessionMode in GeminiAgent and setMode in Session to handle mode changes and validation, enabling runtime adjustment of approval modes.
• Enhanced Session Responses: Enhanced session creation and continuation responses to include available approval modes and the current active mode, providing clients with up-to-date session status.
• Dynamic Mode Listing: Added a buildAvailableModes utility function to dynamically determine and list available approval modes based on feature flags, such as isPlanEnabled.

Changelog

• packages/cli/src/zed-integration/zedIntegration.test.ts
  • Added mocks for getApprovalMode and isPlanEnabled in the test setup.
  • Introduced new tests to verify that session creation returns correct available and current modes, depending on whether the 'plan' mode is enabled.
  • Added tests for the setSessionMode functionality, including successful mode delegation and error handling for non-existent sessions or invalid modes.
• packages/cli/src/zed-integration/zedIntegration.ts
  • Imported ApprovalMode enum.
  • Modified newSession and continueSession methods in GeminiAgent to include modes (available and current) in their responses.
  • Implemented setSessionMode in GeminiAgent to delegate mode changes to the specific session.
  • Added setMode method to the Session class, which validates the requested mode and updates the configuration.
  • Created a new helper function buildAvailableModes to construct the list of available session modes dynamically.

Activity

• The author, Mervap, has added/updated tests for the new functionality.
• The changes have been validated on MacOS using npm run.
• This PR addresses and fixes issue Acp/ZedIntegration Set Approval Mode (set_mode) #18890.

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[gemini-code-assist]

Code Review

This pull request adds support for the ACP set_mode interface, allowing clients to change the approval mode at runtime. The changes include new methods in GeminiAgent and Session to handle this, along with corresponding tests. The implementation is mostly correct, but I've found one issue regarding validation in Session.setMode that should be addressed to make the implementation more robust.

[sripasg]

@Mervap - can you please check the test failures ? Thanks !

[Mervap]

@sripasg Should be fixed now

[sripasg]

There seems to minor test expectation issue and a lint issue. Please fix these .. otherwise LGTM ! One of us will approve as soon as the tests pass.

[Mervap]

One more try 😶