MCPControl provides 21 well-defined tools with consistent naming conventions (verb_noun pattern: get_*, click_*, move_*, etc.) and complete input schemas using Zod validation. Tool descriptions are substantive (ranging 75-250 chars) and explain what each tool does. However, output schemas are not documented, tool responses are not specified in the code, making it impossible to verify what fields agents should expect. Error handling guidance is absent; tools do not indicate what happens on failure or how to recover. Parameter descriptions are clear but sparse in some cases (e.g., 'Key to press' lacks specifics on valid key names). No tool annotations (readOnlyHint, destructiveHint) are present despite ~60% of tools being destructive (mouse clicks, keyboard input, clipboard writes, window manipulation). Security concerns exist: clipboard operations expose raw system state; no indication of permission gates, rate limits, or audit logging. Overall, definitions are above-average in structure and naming clarity but weak in output specification, error guidance, and security declaration.

• Document output schemas for all tools. Example for get_screenshot: 'Returns {"image_data": string (base64), "width": number, "height": number, "format": string}'. Example for get_screen_size: 'Returns {"width": number (pixels), "height": number (pixels)}'. This enables LLMs to chain tools correctly and extract required fields.
• Add error handling guidance to tool descriptions. Example: 'click_at: If coordinates are outside the screen bounds, returns an error with the valid range. Retry with corrected coordinates.' Example: 'type_text: If the input field is not focused, returns an error. Call focus_window() first to ensure the target window has focus.'
• Annotate all tools with destructiveHint and readOnlyHint. Mark read-only tools: {"destructiveHint": false}. Mark destructive tools: {"destructiveHint": true}. This distinguishes 'click_at' (irreversible action) from 'get_screenshot' (safe to retry) at a glance.
• Enumerate valid key names for press_key and hold_key. Update description to: 'Key to press or hold. Valid keys: enter, tab, escape, shift, ctrl, alt, cmd, backspace, delete, space, arrow_up, arrow_down, arrow_left, arrow_right, home, end, page_up, page_down, f1 - f12, a - z, 0 - 9, etc.'
• Add scope declarations to clipboard tools. Example: 'get_clipboard_content (scope: read:clipboard)' and 'set_clipboard_content (scope: write:clipboard)'. Include security note: 'Warning: clipboard may contain sensitive data (passwords, tokens). Only grant write:clipboard to trusted agents.'
• Declare idempotency for mouse/keyboard tools. Add to descriptions: 'This tool is idempotent: calling it multiple times with the same parameters produces the same result.' For non-idempotent tools, explicitly state: 'This tool is NOT idempotent: calling it multiple times may produce different results (e.g., scroll_mouse scrolls from the current position, not to an absolute position). Use with caution in retry loops.'

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

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