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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false and non-destructive, so the safety profile is covered. The description adds a genuinely useful behavioral fact — that the tool does not compute a price but points to where rates are published/enquiries are taken — which is context beyond the annotations. It stops short of describing what the returned quote source looks like or any auth/rate constraints.

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 short sentences with no filler, and the core point is reasonably front-loaded. The clipped 'Price it:' opener is punchy but slightly at odds with the need for precision in an agent-facing definition.

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?

An output schema exists and annotations cover the safety profile, so return-format explanation is not required. The remaining gap is parameter meaning: three undocumented inputs with 0% schema coverage leave the agent guessing what market and decision_id should contain, which is material for correct invocation.

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 0% for three parameters (banner, market, decision_id), so the description carries the full burden and largely fails it. Only 'banner' is obliquely referenced via 'the banner's own media program'; market and decision_id receive no explanation at all. With sub-50% coverage the description should compensate but does not.

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 domain-specific purpose: returning where the banner's media program publishes rates or takes an enquiry, and clarifies that GSC itself never prices. However, the framing ('Price it:') is cryptic and the actual verb+resource ('returns a quote source') is only inferable, not stated plainly. It does implicitly separate this from pricing/renewal siblings but without naming them.

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?

There is no explicit when-to-use or when-not-to-use guidance. The statement 'GSC never prices; a quote comes from the retailer's program' explains the domain model but does not tell the agent when to call quote_package versus list_packages, submit_demand, or renew_package. Usage is left entirely to inference.

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