Summary

ACP extension command behavior is implemented in packages/cli/src/acp/commands/extensions.ts, but test coverage was missing for important error paths in the disable/uninstall flows.

Problem

Two failure scenarios were not explicitly covered:

1. DisableExtensionCommand when extensionManager.disableExtension(...) throws.
2. UninstallExtensionCommand when extensionManager.uninstallExtension(...) throws for a non-existent extension.

Without explicit tests for these branches, regressions in user-facing error reporting can slip through.

Proposed Solution

Add and maintain test coverage in:

• packages/cli/src/acp/commands/extensions.test.ts

New test cases:

• returns error when disabling fails
• returns error when uninstalling a non-existent extension

Each test should assert the exact command output format to ensure stable, user-facing error messages.

Acceptance Criteria

• The ACP extensions test suite includes explicit coverage for both error paths above.
• Error output includes the extension name and propagated error message.
• Targeted test command passes:

npm run test --workspace @google/gemini-cli -- src/acp/commands/extensions.test.ts

Related PR

Related to #22798