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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real behavioral context beyond them: the tool internally renders a PDF with pdf.js and reads the text back, and in file mode it narrows the comparison to only the name, summary and bullets supplied in the fields. It stops short of noting cost or latency of the render-and-parse step, which is the only remaining gap.

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 when-to-use condition is front-loaded in the first clause, followed by mechanism and then explicit non-goals — a sensible order. The sentences are long and clause-dense (the first sentence packs trigger, mechanism, and three report categories), but every clause carries information and nothing is repeated.

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 13-parameter tool with nested objects, this is close to complete: it explains the two input modes, what the output verifies, and what the tool refuses to do, and an output schema exists so return formatting need not be described. The only omission is guidance on what a passing versus failing check looks like in practice, which would help an agent interpret results.

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 the schema already documents all 13 parameters, including the nested file object, template, page_size and fit_to_one_page. The description's only added parameter meaning is that supplying file switches the tool to checking that uploaded document and restricts comparison scope — a useful nuance, but marginal against a fully documented schema, so the baseline 3 applies.

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 and resource — confirm that a resume PDF has machine-readable text — and enumerates exactly what is reported (page count, top-to-bottom text flow, missing or out-of-order headings and bullets). It explicitly names the sibling generate_resume_pdf and explains the relationship (it builds the same PDF from the same fields), so an agent can separate the two without opening either 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?

"Use this when the user wants to confirm..." gives an explicit trigger, and the description spells out the two operating modes: build-and-check from fields, or check an uploaded PDF via the optional file parameter. It also names when-not: it does not score the resume, rewrite it, or predict ATS ranking, which steers the agent away from using it as an evaluation tool.

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