React Native MCP has 16 tools with complete input schemas and descriptions, but quality is inconsistent. Naming follows verb_noun convention well (get_orientation, take_screenshot, tap, swipe). However, descriptions are terse (avg ~40 chars, well below the 194-char baseline for A+ tools) and lack context on WHEN to use each tool or what happens on failure. Parameters are typed but many lack detailed constraints (e.g., 'selector' accepts 'CSS-like' but no format spec; 'orientation' is a number with no enum or range). Output schemas are not documented anywhere in the provided source. Error handling is absent, no guidance on recovery, retryability, or actionable error messages. The tool set is well-composed (each does one thing) and idempotent (read-only tools are safe; write tools are discrete actions), but lacks the LLM-optimization depth expected of production tools.

• Expand all tool descriptions to 100 - 200 characters. Include: (1) what the tool does, (2) when to use it vs similar tools, (3) what it returns or asserts. Example: 'Tap at specified coordinates. Use for button clicks, menu items, or UI interactions. Returns success or error with coordinates attempted.'
• Document output schemas for all tools. For query_selector, specify: {elements: [{uid, text, x, y, width, height, visible}], total}. For describe_ui: {tree: string, componentCount: number}. For take_screenshot: {base64: string, width, height}.
• Add explicit enums and ranges to parameters. Change 'orientation' from bare number to enum: 0|1|2|3 (or PORTRAIT|LANDSCAPE|etc.). Change 'direction' to enum: up|down|left|right. Add format/pattern to 'selector' (e.g., 'CSS selector syntax, e.g., #id, .class, [attr=value]').
• Add error handling guidance to write tools (tap, swipe, input_text, evaluate_script). Example: 'If element not found, call query_selector first to verify it exists. If script fails, check syntax and return the error message for LLM debugging.'
• Clarify tool relationships in descriptions. For input_text vs type_text: 'input_text types into the currently focused field (faster, no lookup). type_text targets a specific element by uid (use after query_selector). For assert_visible vs query_selector: 'assert_visible checks visibility and fails if not found (for assertions). query_selector returns element details for further interaction.'

Inferred effective spec: <=2025-11-25.

• Relies on Logging (deprecated) - log to stderr or use OpenTelemetry