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

Annotations only cover the safety profile (read-only, closed-world), so the description carries the substantive disclosure: the output is classification-based pairs with named shared categories/tags, it is a review prompt rather than proof of redundancy, and it deliberately never recommends cancellation or totals cost because plan/seat count is unknown. That is meaningful context an agent cannot get from the annotations.

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?

Front-loaded with the trigger condition and tightly packed with routing and limitation info, but slightly redundant — the 'never recommends cancelling' and 'never totals cost' clauses restate the same non-actionable-output point and could be compressed.

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?

There is no output schema, so the description correctly specifies what comes back (overlapping pairs with shared categories and capability tags) and what will not (cost totals, cancellation advice). Combined with the trigger and exclusion guidance, nothing needed to call it correctly is missing.

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 baseline is 3, but the description adds real guidance on the tools parameter ("give it the tools they actually pay for"), scoping input to paid products rather than tools merely used or evaluated. response_format semantics are fully covered by the schema, so no further gain.

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 resource (detect duplicate/overlapping paid AI tools) and immediately disambiguates from siblings by naming compare_tools and find_alternatives as different operations. An agent can distinguish this from every sibling without opening a 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?

Gives concrete user phrasings that should trigger it ("are we paying twice", "does our stack overlap"), plus an explicit Not-for list with the correct alternative for each excluded case. When/when-not/alternatives are all present.

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