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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive. The description adds genuinely new behavioral context beyond them: the pricing model ('Free within the daily allowance, then $0.002 USDC per call via x402'), which is relevant for call planning and not present in 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?

Two sentences, front-loaded with the core purpose before the pricing note. The enumerated field list is slightly long but plausibly useful for output expectations; little waste overall.

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?

An output schema exists, so the description need not explain return values, and it does not over-explain them beyond naming fields. With annotations covering safety and the schema covering the parameter, the description is complete for a single-record lookup; only explicit sibling routing 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% and the single id parameter is fully documented with an example (674231-2026), so the schema carries the burden. The description only restates that it takes a publication number, adding no format or validation detail beyond the schema; 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?

States a specific verb and resource: fetch 'One TED notice by publication number,' and enumerates the fields returned (title, buyer, value, deadline, CPV, place, winners). The singular-by-ID framing implicitly contrasts with the sibling eu-tenders__search, but it never names or explicitly distinguishes the sibling.

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: an agent infers it should use this tool when it holds a TED publication number rather than search criteria. There is no explicit when-to-use, when-not-to-use, or named alternative (eu-tenders__search), leaving routing to inference.

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