pyxel-mcp

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

With no annotations provided, the description carries full burden but provides minimal behavioral information. It mentions what the tool detects (text positions, balance issues) but doesn't disclose execution characteristics like whether it's read-only/destructive, permission requirements, rate limits, or what happens on timeout. For a tool with 3 parameters and no annotation coverage, this is inadequate.

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 well-structured with purpose statement, functional details, and parameter explanations in separate sections. It's appropriately sized with no redundant information. The parameter section could be slightly more concise, but overall it's efficient and front-loaded with the core purpose.

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 3 parameters with 0% schema coverage but good parameter documentation in the description, plus the existence of an output schema (which means return values don't need explanation), the description is moderately complete. However, for a tool that analyzes visual layouts and runs scripts, more behavioral context about execution and results would be helpful despite the output schema.

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?

The description includes an 'Args' section that explains all 3 parameters with meaningful context beyond the schema (which has 0% description coverage). It clarifies that script_path is 'Absolute path to the .py script to run', frames is 'Frame number to analyze' with default, and timeout is 'Maximum seconds to wait'. This fully compensates for the schema's lack of descriptions.

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 tool's purpose: 'Analyze screen layout, text alignment, and visual balance' with specific verbs like 'detects', 'checks', and 'identifies'. It distinguishes from siblings like inspect_screen or inspect_sprite by focusing on layout analysis rather than general screen inspection or sprite-specific checks. However, it doesn't explicitly contrast with all siblings.

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 provides some usage context: 'Use this to verify UI layout quality' which implies when to use it. However, it doesn't explicitly state when NOT to use it or mention alternatives among the many sibling tools (e.g., when to use inspect_screen instead). The guidance is implied rather than explicit.

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