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

Beyond the readOnly/openWorld annotations, the description discloses the data source ('via a Turkish residential proxy'), the exact cost model ($0.01 USDC per successful call), accepted payment rails (x402 on Base, Solana or Arc), and that failed calls are not charged. These are material operational facts an agent cannot infer from structured fields.

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?

Purpose is front-loaded in the first clause, followed by a dense but relevant field list and a separate payment sentence. The long enumeration of return fields is somewhat redundant given the output schema, but overall it is efficient and wastes little space.

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?

Given an output schema exists, the description is more than complete for a two-parameter read tool: it covers source, pricing, payment rails, and failure charging. Minor gaps remain around rate limits or proxy-related failures, but nothing critical for correct invocation 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 both query and page are already documented, including the '1-50' page range and Turkish query examples. The description adds the page size ('36 products per page') and currency for price, but does not clarify parameter behavior beyond the schema, so baseline 3 applies.

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 opens with a specific verb and resource ('Trendyol (Turkey) product search') and scopes it to a named marketplace and country, which clearly distinguishes it from sibling marketplace tools like ecommerce_hepsiburada or ecommerce_digikala_iran. An agent can identify exactly what this tool retrieves without opening the 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?

Usage is implied by the marketplace scope, and the schema's query description notes Turkish works best, but the description never says when to prefer this over a sibling such as ecommerce_hepsiburada for Turkish e-commerce or when to avoid it. No explicit exclusions or alternatives are given.

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