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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. Beyond that, the description supplies genuine context: no API key is needed over stdio, and the return payload includes title, price, file info and a /m/<hash> market page URL — details 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 core purpose, then filtering, then the return shape, then the auth note — a sensible ordering. There is minor redundancy between 'Search and browse' and 'Filter by keyword, category, and paginate', but no wasted sentence.

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?

Four optional parameters are fully covered by the schema and an output schema exists, so the description need not explain return values in depth. What it lacks is the relational context — how results lead into purchase_asset or get_download_url, and what 'active' excludes — but nothing prevents a correct call.

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 100%, with q, page, pageSize and the category enum all documented inline, so the baseline is 3. The description only restates that filtering happens by keyword, category and pagination, adding no defaults, limits or syntax beyond 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 pair and resource — 'Search and browse active listings on the Payaion marketplace' — with the scope qualifier 'active'. It does not explicitly distinguish itself from the closest sibling, list_on_marketplace, so an agent must infer that one browses others' listings and the other publishes its own.

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?

Mentions what can be filtered and that results paginate, which implies the discovery use case, and adds 'No API key required over stdio' as an environment note. However, it never states when to choose this over list_on_marketplace, nor that browsing is the natural precursor to purchase_asset or get_download_url.

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