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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, and the description adds genuinely new context beyond them: selectable text in reading order, a plain-text and JSON copy, page count, whether fit_to_one_page succeeded, and that download links expire in about an hour. The statement that it 'lays out only the text given' and does not embellish or verify is important behavioral information that no annotation conveys.

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 trigger condition is front-loaded and each sentence carries distinct information (returns, templates, scope limits, link expiry). The parenthetical list of resume fields partially duplicates the schema's own section names, which is the only mildly redundant element in an otherwise dense paragraph.

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 12-parameter generation tool, the description covers trigger, scope limits, output characteristics and a practical caveat about expiring download links. An output schema exists, so the description's brief mention of return values is a bonus rather than a gap, and nothing an agent needs to call this correctly 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 description coverage is 100%, so every one of the 12 parameters is already documented with examples and constraints in the schema. The description restates the content sections and mentions the three templates and two page sizes, but adds no format, default, or interaction detail (e.g., how fit_to_one_page interacts with template choice) that the schema does not already carry.

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 ('generate a resume PDF from facts they provide') and scopes it tightly by enumerating the content sections it lays out. It also draws a boundary against sibling functionality by saying it 'does not write, embellish or verify resume content', which separates it from check_resume_text without needing to name it.

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 opening clause gives an explicit trigger ('Use this when the user wants their resume as a PDF file from facts they provide'), and the exclusions ('Does not make cover letters, Word files, two-column designs or photos') tell the agent when not to call it. The alternative tool check_resume_text is never named, so the routing guidance is strong but not fully explicit.

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