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

Annotations already cover read-only, idempotent, non-destructive and closed-world, so the bar is lower; the description adds genuinely new behavior by disclosing the cost model (no credits) and the source-resolution rule (latest CV in Litjob unless cv_text is supplied). It does not describe the shape of the returned gap analysis, but with annotations carrying the safety profile this is solid.

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 compact sentence with the output definition front-loaded and the cost note appended. No wasted clauses, though the nested parenthetical makes it slightly harder to parse than a plain declarative sentence.

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?

No output schema exists, so the description should say what the agent gets back (a list of missing keywords, presumably with some scoring), and it should clarify what happens when neither job_id nor job_text is supplied given zero required parameters. What is present is accurate but leaves these gaps for a tool the agent will call blind.

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 100%, so the schema documents job_id, cv_text and job_text with defaults and max lengths. The description only reinforces the cv_text default; it adds nothing about how job_id and job_text interact despite zero required parameters, which is the one genuinely ambiguous point.

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 output: the skills/keywords from a job ad that are absent from the user's CV, which is clearly distinguishable from extract_job_keywords (extraction only) and find_job_matches (matching, not gap analysis). It is framed as a question rather than a verb phrase, which slightly softens the directive, and no sibling is named explicitly.

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 is implied by the phrase 'missing from the user's CV' against a job ad, and the 'Free: no credits used' note is a helpful selection signal versus credit-consuming siblings like tailor_application. However, there is no explicit when-to-use/when-not guidance and no mention of how this differs from extract_job_keywords.

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