feat: add external MCP server integration for enhance prompt

[roomote]

Summary

This PR implements external MCP (Model Context Protocol) server integration for the "Enhance Prompt" functionality in RooCode, as requested in #6631.

Changes

1. Added new settings to provider-settings schema

• Added enhancePrompt object with:
  • useExternalServer: boolean to enable/disable external server
  • endpoint: URL string for the external MCP server endpoint

2. Updated MessageEnhancer

• Added logic to check for external server configuration
• Routes enhancement requests to external server when enabled
• Includes context messages in the request payload
• Falls back to default internal enhancement on failure
• Uses getModelId helper for consistent model ID extraction

3. Added comprehensive tests

• Tests for successful external server enhancement
• Tests for context message inclusion
• Tests for various fallback scenarios (network errors, non-ok responses, missing fields)
• Tests for configuration validation
• Tests for different provider model ID fields

API Contract

When external server is enabled, MessageEnhancer sends a POST request to the configured endpoint with:

{
  "prompt": "raw user prompt",
  "context": [
    { "role": "user", "content": "..." },
    { "role": "assistant", "content": "..." }
  ],
  "model": "model-id"
}

Expected response:

{
  "enhancedPrompt": "enhanced prompt text"
}

Benefits

✅ Allows prompt enhancement logic to be modular and externalized
✅ Supports local DSPy servers, memory augmentation, and custom enhancement pipelines
✅ Makes RooCode more extensible for power users and enterprise setups
✅ Fully backward compatible - feature is opt-in via settings
✅ Graceful fallback to internal enhancement if external server fails

Testing

• All existing tests pass
• Added 8 new tests for external MCP server functionality
• TypeScript compilation successful
• Linting checks pass

Fixes #6631

---

Important

Adds external MCP server integration to MessageEnhancer with fallback to internal enhancement and updates provider settings schema.

• Behavior:
  • Adds external MCP server integration to MessageEnhancer in messageEnhancer.ts.
  • Routes enhancement requests to external server if useExternalServer is true and endpoint is set.
  • Falls back to internal enhancement if external server fails or response is invalid.
  • Includes context messages in external server requests.
• Settings:
  • Adds enhancePrompt object to provider-settings.ts with useExternalServer and endpoint fields.
• Tests:
  • Adds tests in messageEnhancer.test.ts for external server usage, context inclusion, and fallback scenarios.
  • Tests handle network errors, non-ok responses, and missing fields in server response.

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[roomote]

I reviewed my own code and found it surprisingly coherent. The machines are learning.

[roomote]

Consider adding JSDoc comments to document these new settings:

Suggested change

	enhancePrompt: z
	// External MCP server settings for enhance prompt
	/**
	* Configuration for external MCP server integration
	* @property {boolean} useExternalServer - Enable routing enhancement requests to external server
	* @property {string} endpoint - URL endpoint of the external MCP server
	*/
	enhancePrompt: z

[roomote]

The error logging could be more descriptive to help with debugging. Consider:

Suggested change

	console.error("Failed to enhance prompt via external server:", err)
	} catch (err) {
	console.error(`Failed to enhance prompt via external server (${configToUse.enhancePrompt.endpoint}):`, err)
	// Fallback to default logic

[roomote]

Consider adding a timeout to prevent hanging requests. You could use AbortController:

Suggested change

	const response = await fetch(configToUse.enhancePrompt.endpoint, {
	// Make request to external MCP server
	const controller = new AbortController()
	const timeoutId = setTimeout(() => controller.abort(), 10000) // 10 second timeout
	const response = await fetch(configToUse.enhancePrompt.endpoint, {
	method: "POST",
	headers: { "Content-Type": "application/json" },
	signal: controller.signal,
	body: JSON.stringify({
	prompt: text,
	context: contextMessages,
	model: getModelId(configToUse) || "unknown",
	}),
	})
	clearTimeout(timeoutId)

[roomote]

Great implementation! Just a thought - should we add UI components to configure these settings in the settings panel? Currently users would need to manually edit their settings.json. We could add controls similar to other provider settings.

[roomote]

For production use, should we restrict the endpoint to HTTPS only? Also, consider if we need to support authentication headers for secured endpoints in the future.

[daniel-lxs]

Not approved yet, closing