firefox-devtools-mcp

# Future Features This document tracks features that are planned or considered for future implementation but are currently disabled or not yet implemented. ## Disabled Features ### `evaluate_script` Tool **Status:** Temporarily Disabled **Reason:** Needs further consideration for security and use case validation **Implementation:** Fully implemented in `src/tools/script.ts` #### Description The `evaluate_script` tool allows executing arbitrary JavaScript functions inside the currently selected browser page. It supports: - Synchronous and async functions - Passing arguments via UIDs from snapshots - Timeout protection against infinite loops - JSON-serializable return values #### Example Usage ```json { "function": "() => document.title", "timeout": 5000 } ``` ```json { "function": "(el) => el.innerText", "args": [{ "uid": "abc123" }] } ``` #### Security Considerations This tool allows executing arbitrary JavaScript in the browser context, which requires careful consideration: 1. **Sandboxing:** Scripts run in the page context with full DOM access 2. **Timeout Protection:** Default 5s timeout prevents infinite loops 3. **Size Limits:** Functions limited to 16KB 4. **Return Values:** Must be JSON-serializable #### Future Work Before re-enabling this tool, consider: - [ ] Add explicit security warnings in tool description - [ ] Document safe usage patterns and anti-patterns - [ ] Consider adding a "safe mode" with restricted APIs - [ ] Add example use cases to documentation - [ ] Evaluate if snapshot + UID-based tools cover most use cases #### Re-enabling To re-enable this tool: 1. Uncomment exports in `src/tools/index.ts` 2. Uncomment handler registration in `src/index.ts` 3. Uncomment tool definition in `src/index.ts` allTools array 4. Update documentation with security guidelines 5. Run tests: `npm test -- script` --- ## Planned Features ### BiDi Native Tab Management **Status:** Planned **Priority:** High Currently, tab management uses Selenium WebDriver's window handles. Future versions should use Firefox BiDi's native `browsingContext` API for: - Better performance - More reliable tab metadata - Real-time tab updates - Window management **Implementation Location:** `src/firefox/pages.ts` ### Console Message Filtering by Source **Status:** Planned **Priority:** Medium Add ability to filter console messages by source (realm/context): ```json { "level": "error", "source": "worker", "limit": 10 } ``` **Implementation Location:** `src/tools/console.ts` ### Network Request Body Capture **Status:** Planned **Priority:** Medium Capture and expose request/response bodies for network requests: - POST/PUT request bodies - Response bodies (with size limits) - Binary data handling **Implementation Location:** `src/firefox/events/network.ts` ### Advanced Performance Profiling **Status:** Planned **Priority:** Low **Note:** Basic performance metrics are available via Navigation Timing API (not exposed as MCP tools) Full performance profiling support would include: - CPU profiling - Memory snapshots - FPS monitoring - Long task detection - Custom performance marks and measures **Reason for deferral:** WebDriver BiDi does not currently provide advanced profiling APIs. Use Firefox DevTools UI Performance panel for advanced profiling. **Previous implementation:** Performance tools were removed in PERFORMANCE-01 task due to limited BiDi support and complexity for minimal value. --- ## Rejected Features None yet. --- ## Contributing Have an idea for a new feature? Please: 1. Check this document first 2. Open an issue with the `feature-request` label 3. Describe the use case and benefits 4. Consider security and performance implications