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

Annotations already convey the read-only, idempotent, and non-destructive nature. The description adds behavioral detail about how the tool analyzes parsing issues and returns actionable fixes, and the W3C validator analogy gives a concrete mental model. It does not contradict annotations, and there are no hidden side effects mentioned.

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—two sentences that front-load the core action, detail the checks performed, and describe the output. Every sentence earns its place, using the W3C validator analogy for quick comprehension. No fluff or redundancy.

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 tool with a single parameter and an output schema, the description covers the purpose, input constraints, method, and output type. It is complete enough for an agent to correctly select and invoke the tool without additional context. The sibling tools are clearly different in scope.

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?

The input schema already fully describes the only parameter (url) with its type and accepted formats. The description does not add significant new parameter-specific semantics beyond what the schema provides. With 100% schema coverage, the baseline of 3 is appropriate.

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 clearly states the tool checks resumes for ATS compatibility, listing specific checks (text extractability, email/phone/sections, multi-column layouts, tables, emoji). It is distinguished from sibling tools by focusing on resumes and using the W3C validator analogy, making the purpose unambiguous.

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 a resume needs ATS parsing validation. It provides clear context about the input (PDF/.docx URL) and the type of output (score and fixes). However, it does not explicitly mention alternatives or exclusions, such as when to use check_job instead.

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