pyxel-mcp

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden. It discloses that the tool runs a script, captures at a specific frame, and has a timeout, which are useful behavioral traits. However, it does not mention potential side effects (e.g., if the script execution modifies state), error handling, or performance implications, leaving gaps in transparency.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is appropriately sized and front-loaded, starting with the core purpose, then detailing the return format, and finally listing parameters with brief explanations. Every sentence adds value without redundancy, making it efficient and well-structured.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the complexity of running a script and capturing screen data, with no annotations but an output schema (implied by 'Returns'), the description is fairly complete. It covers the tool's purpose, output format, and parameters, but could benefit from more behavioral context (e.g., error cases or prerequisites) to fully compensate for the lack of annotations.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate. It adds meaning by explaining that 'script_path' is an absolute path to a .py script, 'frames' is the frame number to capture with a default, and 'timeout' is the maximum wait time in seconds. This clarifies the purpose and usage of parameters beyond the bare schema, though it could provide more detail on format constraints.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the specific action ('Capture screen as a compact color index grid') and distinguishes it from siblings by specifying it returns Pyxel palette indices in a 2D array format, unlike tools like 'capture_frames' or 'play_and_capture' which likely handle different capture methods or outputs.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage for programmatic comparison of screen contents in a compact format, but does not explicitly state when to use this tool versus alternatives like 'capture_frames' or 'compare_frames'. It provides context but lacks explicit guidance on exclusions or comparisons.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.