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

With no annotations, the description carries the full burden and does substantial work: it discloses the billing model ('charged the product's listed price per call via x402 (USDC on Base)') and what the response contains (provenance chain, Ed25519 attestation). It omits failure/refund behavior and rate limits, but the cost and payment disclosures are exactly the kind of context annotations would otherwise have to supply.

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?

Two sentences with no filler; the core action comes first and the routing pointer and payment/response details follow. Every clause carries information an agent needs.

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 output schema the description must characterize returns, and it does so at a high level (provenance chain, attestation) though not the actual payload shape. Combined with the cost model and the search_catalog pointer, an agent has enough to invoke it, but the 'params' object's expected keys remain underspecified.

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 67% and the description adds real meaning on top: it establishes that 'slug' selects the catalog product and that slugs/prices/params are sourced via search_catalog, and it frames 'params' as the product's own query params. The payment parameter is already documented in the schema, so credit there is limited.

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 states a specific verb and resource ('Buy one call of any catalog product by slug') and immediately delimits scope ('including datasets that have no tool of their own'). An agent can distinguish this from the sibling search_catalog without opening either 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?

It routes the agent explicitly to search_catalog for finding slugs, prices and params, and clarifies which products are reachable through this tool. It stops short of stating when NOT to use it (e.g. when a dedicated sibling tool already exists), so it is clear context rather than full when/when-not guidance.

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