Extraer texto de un PDF

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

Annotations already cover the safety profile (readOnlyHint, destructiveHint=false, openWorldHint), so the description's added value is the hard operational limits: 5 MB max, 20 pages per call, and the critical caveat that scanned PDFs return empty because there is no OCR. That last point is exactly the kind of failure-mode disclosure annotations cannot provide.

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?

Two sentences, zero filler. The core action and its size/page constraints are front-loaded, and the no-OCR limitation is placed last as a caution.

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?

An output schema exists, so return-format details are legitimately omitted, and the description covers size, page, and OCR boundaries. It stops short of noting whether non-PDF or non-direct URLs fail and how the text/json format choice affects downstream use.

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 100%, so url, pages and format are already documented, including the 1-indexed range syntax and the enum values. The description's "pages selects a range" restates the schema and it never mentions the format parameter, so it adds little beyond 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?

States a specific verb+resource ("Extract text from a PDF") and immediately qualifies it with the required input form ("at a direct URL"). No sibling tool performs PDF text extraction, so an agent can select this unambiguously without opening the schema.

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?

Usage conditions are implied rather than stated: the agent learns it needs a direct URL and that pages selects a range, but nothing says when to reach for this instead of download_resource or how to handle a scanned PDF once it returns empty. Adequate but no explicit when/when-not guidance.

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