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

Annotations already declare readOnlyHint=true, idempotentHint=true and openWorldHint=false, so the safety profile is covered. The description adds real behavioral value beyond that: it discloses what classes of problems are reported (vague superlatives, promises without proof, results without mechanism, generic CTAs) and that output includes remediation suggestions ('tells you how to fix each one').

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?

Five sentences, front-loaded with the core purpose before the examples and the sibling hand-off. Each sentence carries distinct information (what it catches, that it proposes fixes, when to use, when to use something else), though the detection list is slightly repetitive.

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 single-parameter, read-only checker with no output schema, the description covers purpose, detection scope, remediation behavior and fallback routing. The only gap is concrete input formatting for the claims array, which is a minor omission given the schema fields.

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 description references the input conceptually ('claims like ...', 'any button text'), which maps loosely to the claims text and type fields, but it gives no format or batching guidance. Schema description coverage is reported as 0%, so the description does not fully compensate for the parameter documentation gap, though the nested schema itself is self-describing.

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?

Specific verb+resource: it checks marketing claims and CTAs and says exactly what it detects (vague superlatives, unproven promises, generic buttons). It also distinguishes itself from the sibling check_headlines, which 'does the full job' for headlines, so an agent can route correctly 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?

Explicit when-to-use with concrete examples ('results in days', 'trusted by thousands', '#1 tool', any button text) plus an explicit boundary: for headlines, use check_headlines instead. Nothing about routing is left to inference.

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