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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the description's job is to add substance — and it does, disclosing the inclusion rule ('explicit platform support, excluding tools marked only as any-store') and the freshness caveat of oldest last-checked dates. The odd mention of 'counts' alongside 'IDs and names' leaves the return shape slightly muddled, keeping it off a 5.

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 with the core purpose front-loaded, so the agent gets the point immediately. The trailing sentence packs several loosely related facts (counts, source links, last-checked dates) that read as a compressed return-value dump rather than a clean statement.

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?

With no parameters and no output schema, the description carries the burden of explaining what comes back, and it does name the fields returned. Those field names ('counts', 'oldest available last checked dates') are described opaquely enough that an agent still can't fully predict the payload shape.

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 tool takes zero parameters, which is the baseline-4 case: there is nothing for the description to disambiguate, and it correctly signals a no-argument enumeration.

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 — 'List commerce platform IDs and names' — and scopes it to feeding the platform filter, which clearly separates it from tool-search siblings like search_tools or get_tool. It never names an alternative, but the distinct resource makes the distinction unambiguous.

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?

The phrase 'for the platform filter' implies when an agent would want this list, but there is no explicit when-to-use guidance, no statement of what to do with the result, and no mention of alternatives or prerequisites.

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