fix(cli): treat unknown slash commands as regular input instead of showing error

[skyvanguard]

Summary

Fixes #17003

File paths starting with / (e.g., /usr/local/bin, /etc/config) are incorrectly parsed as slash commands, showing an "Unknown command" error instead of being sent to Gemini as regular text input.

Changes

• Unknown commands now fall through as regular input: When a /-prefixed input doesn't match any registered command and MCP servers are fully loaded, handleSlashCommand returns false, allowing the input to be processed as a normal query by Gemini.
• MCP loading edge case handled: If MCP servers are still discovering commands (MCPDiscoveryState.IN_PROGRESS), a warning is displayed since the command might exist but hasn't been registered yet.
• History duplication fix: Moved addToHistory call to after command parsing, preventing the input from being added to history when it's going to be treated as regular text (the caller handles history in that case).
• Dead code removal: Removed unreachable "Unknown command" error block at the end of the try block.

How it works

The routing flow in prepareQueryForGemini (useGeminiStream.ts:449-451) already handles the false return:

if (isSlashCommand(query)) {
  const result = await handleSlashCommand(query);
  if (result !== false) return; // Command was handled
}
// Falls through to send as regular Gemini query

Comparison with #17009

This PR improves upon the approach in #17009:

• Properly handles the MCP loading state instead of removing the check entirely
• Avoids history duplication by restructuring the flow
• All existing tests pass with no CI failures

Test plan

• Unknown commands (e.g., /usr/local/bin) return false and don't add to history
• Unknown commands during MCP loading show appropriate warning
• Known commands (e.g., /help, /quit) continue to work normally
• Case-sensitive matching preserved (/Help returns false)
• All 36 tests in slashCommandProcessor.test.tsx pass
• All 70 tests in useGeminiStream.test.ts pass
• TypeScript compilation: 0 errors

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[gemini-code-assist]

Summary of Changes

Hello @skyvanguard, 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 refines the command-line interface's behavior when encountering inputs that resemble slash commands but are not recognized. The primary goal is to correctly interpret file paths and similar inputs as regular text for the Gemini model, rather than displaying an error. It also introduces better handling for cases where commands might be pending discovery by MCP servers, providing a more informative user experience.

Highlights

• Improved Unknown Command Handling: Unknown slash commands (e.g., file paths) are now treated as regular text input for Gemini if MCP servers are fully loaded, preventing erroneous 'Unknown command' messages.
• MCP Loading State Awareness: If an unknown command is entered while MCP servers are still discovering commands, a warning is displayed, indicating that the command might exist but hasn't been registered yet.
• History Duplication Prevention: The logic for adding input to history has been refactored to occur after command parsing, ensuring that inputs treated as regular text are not duplicated in the history.
• Dead Code Removal: An unreachable 'Unknown command' error block has been removed, streamlining the command processing logic.

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[gemini-code-assist]

Code Review

This pull request effectively addresses the issue of file paths being misinterpreted as slash commands. The core change to treat unknown commands as regular input by returning false from handleSlashCommand is correct and well-implemented. I appreciate the thoughtful handling of the edge case where MCP servers are still loading, providing a helpful warning to the user instead of silently failing. The accompanying fixes for history duplication and removal of dead code improve the overall quality and robustness of the command processor. The test suite has been updated comprehensively to cover the new logic. Overall, this is a solid improvement.

[skyvanguard]

I have signed the CLA. @googlebot I signed it.

[Adib234]

Looks like your email needs CLA, here's a more detailed scan

-- | -- | --
skyvanguard |   | Ok: 🇨
  | skyvanguard@gmail.com | Need CLA
  | noreply@anthropic.com | Need CLA

[skyvanguard]

Looks like your email needs CLA, here's a more detailed scan

-- | -- | --
skyvanguard |   | Ok: 🇨
  | skyvanguard@gmail.com | Need CLA
  | noreply@anthropic.com | Need CLA

My email is: skyvanguard.ia@gmail.com

[Adib234]

Right, i think skyvanguard@gmail.com | Need CLA means that you need to get CLA for your email