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

Annotations already declare readOnly/openWorld/non-idempotent, and the description adds real context beyond them: the 1-credit default cost, that repeated calls may charge again (reinforcing non-idempotency), and an untrusted-data warning. What's missing is disclosure of pagination caps or result-volume behavior for a 43-param query.

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?

Three short sentences, front-loaded with the purpose, then cost and trust caveats. No wasted text. It is arguably too compressed for a 43-parameter tool, but every sentence earns its place.

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 wide, filter-heavy, non-idempotent query with no output schema, the description covers cost and data trust but says nothing about expected return shape (keyword rows with metrics), result caps, or how the many min/max filters interact. Adequate but with clear gaps against this complexity.

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 carries parameter meaning and the baseline is 3. The description adds nothing parameter-specific beyond the generic 'market filters' phrase and the ASIN-list input, leaving ambiguous fields like queryType and historyDate entirely to the schema.

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: 'Expand traffic keywords from an ASIN list with market filters.' An agent can tell it produces keyword expansions from ASINs. However, it never distinguishes itself from near-neighbors like amazon_traffic_keyword, amazon_traffic_source, or amazon_keyword_miner, so sibling disambiguation is left to the schemas.

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 only implied by the required params (asinList, marketplace, queryType) and the phrase 'from an ASIN list.' There is no explicit when-to-use vs when-to-use-an-alternative guidance, and no prerequisite or exclusion statements, which matters with 40+ traffic/keyword siblings.

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