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

With no annotations, the description fully carries the transparency burden and meets it exceptionally. It discloses the return shape, enumerates five specific error categories, explains the auto-suggest fix for Tabs namespace misuse, and defines that wrong-library icon imports are errors. This is far beyond a typical tool description.

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?

Though long, every sentence is high-signal. The mandatory directive is front-loaded, the numbered catches make complex rules scannable, and the closing prohibitions are unambiguous. No filler or redundancy; the structure earns its length.

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?

With no output schema, the description correctly explains the return object and its fields. It covers the necessary preconditions (complete code, import from @marmoui/ui), the expected parameters, and the iterative workflow. For a tool of this complexity, nothing significant is missing.

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 coverage is 100%, so baseline is 3. The description adds meaningful semantics for iconLibrary by linking it to get_design_guidelines and clarifying that mismatched imports are errors. Code and context parameters are adequately described in the schema, so the extra value for iconLibrary pushes this to a 4.

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 states a specific verb and resource: 'Validates TSX/JSX against real @marmoui/ui prop signatures'. It clearly differentiates from siblings by framing itself as a mandatory pre-return step for generated code, not just a general validation tool. The scope and outcome are unmistakable.

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?

Provides explicit when-to-use guidance: 'MANDATORY — call this on every piece of code you generate before returning it to the user', plus a clear feedback loop ('If valid=false, fix all errors and call this again') and a hard rule ('DO NOT return code with errors'). It also instructs matching iconLibrary with get_design_guidelines, which is actionable usage context.

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