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

With no annotations provided, the description carries the full behavioral burden. It does add useful context: only public PDFs are supported, the output is a plain text preview, and there is a $0.005 USDC cost. It does not disclose failure behavior, size limits, or truncation details, which would be valuable.

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?

A single, well-structured sentence communicates the action, target, output type, and cost with zero filler. Every word contributes meaning.

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 one-parameter tool, the description is minimally viable: it names the input and output type. However, without annotations or an output schema, it should also clarify what 'preview' means, how much text is returned, and what happens for invalid or inaccessible PDFs.

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 0% and the pdfUrl parameter has no description, so the description must compensate. It clarifies that the parameter should be a public PDF URL, but it does not specify additional format details, download-link requirements, or accessibility constraints.

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?

Description uses the specific verb 'Extracts' with a clear resource: 'plain text preview from public PDF URLs'. This distinguishes it from sibling tools like web_scraper, extract_json, and render_screenshot, making the tool's purpose immediately obvious.

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 implies when to use the tool: when the target is a public PDF URL and plain text is needed. However, it does not explicitly state when not to use it or mention alternatives for non-PDF or private documents, leaving some routing judgment to the agent.

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