pdfmux

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively communicates that this is a read-only operation ('No extraction performed'), describes what information is returned, and implies it's a lightweight operation ('instantly'). However, it doesn't address potential limitations like file size constraints or error conditions.

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 perfectly structured and economical. The first sentence establishes purpose and scope, the second provides crucial behavioral context, and the third offers explicit usage guidance. Every sentence earns its place with no redundant information.

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 moderate complexity (single parameter, read-only operation) and the presence of an output schema (which handles return values), the description provides excellent contextual completeness. It covers purpose, behavioral characteristics, and usage guidance while leveraging the structured data appropriately.

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 schema has 0% description coverage for the single parameter, but the description compensates by implicitly clarifying that 'file_path' refers to a PDF file from which metadata will be extracted. While it doesn't specify format requirements or constraints, it provides enough context to understand the parameter's purpose beyond the bare schema.

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 with specific verbs ('Get PDF metadata') and resources ('PDF'), listing exact metadata types (page count, file size, document type, table presence). It explicitly distinguishes from siblings by stating 'No extraction performed' and naming alternatives, making the scope unambiguous.

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 explicit guidance on when to use this tool ('Use this first to decide which tool to call next') and names specific alternatives (convert_pdf, analyze_pdf, extract_structured) for different use cases. It clearly positions this as an initial diagnostic step before more intensive operations.

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