figma_validate_screen

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

The description declares the tool is 'Read-only — never mutates the file,' which aligns with the readOnlyHint annotation. Additionally, it details the output structure (breakdown includes coverage and overflow objects with specific ratios), adding context beyond the annotation. No contradictions are present.

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 concise with 4-5 sentences covering purpose, usage, version details, and alternatives. It is well-structured with clear sections, though the version note could be slightly more integrated. Overall, it earns its length without unnecessary fluff.

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 tool's complexity (scoring across dimensions, conditional actions) and lack of output schema, the description fully covers the return value (compliance score, breakdown details), usage context, and decision logic. It also mentions version specifics, making it self-contained. No gaps remain.

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 input schema already provides 100% description coverage for all parameters. The description adds value by explaining the context for minScore (threshold for deletion and rebuild) and implying the role of expectedDs (library name for scoring). This goes beyond the schema's basic definitions, meriting a 4 despite the high baseline.

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 explicitly states the tool validates a screen against design-system discipline criteria, returning a compliance score across three dimensions. It distinguishes itself from the sibling tool figma_scan_ds_compliance by specifying that the latter is for hardcoded samples and primitive fallback lists. This provides clear differentiation and a specific verb+resource combination.

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 gives explicit instructions on when to use the tool ('AFTER creating a screen to verify DS compliance') and what action to take based on the result ('If score < minScore, Claude should delete the screen and rebuild it'). It also names an alternative tool for different use cases, offering complete guidance.

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