ReftrixMCP

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

Annotations declare readOnlyHint=true, idempotentHint=true, and openWorldHint=true. The description adds valuable behavioral context beyond these annotations by detailing exactly what layout changes are detected (section visibility, font/grid/spacing changes) and specifying the return format (0-100 score). It does not mention rate limits or error handling scenarios.

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 a single, dense sentence with zero waste. It front-loads the core action (simultaneous capture), specifies the viewports, lists the analysis targets, and defines the return value—all essential information with no filler.

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?

Despite lacking an output schema, the description explicitly states the return value (diff score 0-100) and explains the analysis methodology. Combined with comprehensive annotations and 100% schema coverage, this provides sufficient context for invocation, though error handling scenarios remain undocumented.

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 100%, documenting all parameters including the default viewport values. The description reinforces the default three viewports but does not add syntax details, format constraints, or usage examples beyond what the schema already provides, warranting the baseline score for high-coverage schemas.

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 precisely states the tool captures web pages across three specific viewports (desktop 1920x1080, tablet 768x1024, mobile 375x812) simultaneously, analyzes responsive layout differences (section visibility, fonts, grids, spacing), and returns a diff score (0-100). This clearly distinguishes it from siblings like responsive.search or page.analyze.

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?

While the detailed functional description implies usage scenarios (responsive layout testing), it lacks explicit guidance on when to use this capture tool versus responsive.search (likely for retrieving existing captures) or other analysis tools. No 'when-not' exclusions or alternative recommendations are provided.

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