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

Adds real behavioral context beyond the annotations: no model call, nothing stored, free of charge, and a Pro-plan prerequisite that would otherwise surface only as an error. The parenthetical endpoint wrapper is mildly confusing given the POST verb, but the leading [read-only] tag keeps it consistent with readOnlyHint=true. It does not say what the check returns, which is the main 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?

Two compact sentences: the capability and its sources come first, followed by cost/safety and plan prerequisites. The bracketed [read-only] tag and the endpoint wrapper are terse and no sentence is padding.

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?

With five parameters at low schema coverage and no output schema, the definition should say what a check produces (violations list, pass/fail, matched rules) so an agent can interpret the result. Plan gating and cost are well covered, but the return shape and the two undocumented parameters leave it only minimally complete for a validation tool.

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 only 20%, so the description has to carry more weight. It does map the four context enum values to concrete copy types and hints that 'destinations' is a claims source, but platforms, destination, and how text is scoped are not explained anywhere, so the compensation is only partial.

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 object: it checks a hook, CTA, caption or ad against named claims sources (verified prices, banned phrases, competitors, destinations). That is far more specific than the title. It does not explicitly contrast itself with the sibling cta_check, so an agent must infer the boundary between a claims audit and a CTA check.

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 rather than stated: you submit copy plus a context to validate it before use, and the description notes it is free and requires the Pro plan. There is no explicit when-to-use versus when-not-to-use guidance and no routing to alternatives such as cta_check or hooks_generate when the copy itself needs to be created.

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