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

With no annotations, the description carries the burden of behavioral disclosure. It explicitly states that text content is never generated or altered, only structure is inferred, and it discloses metadata extraction (title/author/page count/date) and a real token count. It does not mention rate limits or failure modes, but the core behavioral traits are clearly disclosed.

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 compact and front-loaded with the core action and input format. The extra details (metadata, token count, sample endpoint, content kit) are useful and each sentence earns its place. It is slightly dense with the parenthetical list of sibling tools, but not bloated.

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?

For a two-parameter tool with no output schema, the description covers the input modes, the output format, the behavioral guarantee, and a sample endpoint. It does not explain the exact structure of the returned Markdown or error cases, but the provided information is sufficient for an agent to invoke it correctly in most cases.

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 0%, so the description must compensate. It explains that the tool accepts a public PDF by HTTPS URL or base64, which directly maps to the two parameters (url and pdf_base64). It does not detail the exact base64 format or URL requirements, but it gives enough semantic meaning for an agent to understand the two input options.

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 ('Extract'), a specific resource ('a public PDF by HTTPS URL or base64'), and a concrete output ('clean Markdown'). It also distinguishes itself from siblings by naming the content kit (pdf, web-read, extract, summarize, detect-language) and pointing to GET /pdf/sample, so an agent can tell it apart from read_web_page and extract_structured.

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 clear context: it handles public PDFs via URL or base64 and produces Markdown. It does not explicitly state when not to use it or name alternatives like read_web_page for non-PDF content, but the content-kit mention and the sample endpoint provide enough context for an agent to select it for PDF-specific extraction.

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