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

Annotations already cover read-only, idempotent, and non-destructive behavior. The description adds value by stating 'no auth' and revealing the privacy boundary: it never exposes who bid what. It also enumerates the exact subset of bidding data returned, going beyond what the annotations express.

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 compact sentences convey the tool's output fields, privacy boundary, and auth requirements without filler. The core scope, one feature's bidding numbers, is front-loaded, and every phrase contributes meaning.

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?

For a one-parameter, read-only tool with no output schema, the description is complete: it lists every returned value, states the auth model, and relies on the already-comprehensive schema for input. No critical missing information prevents correct invocation.

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 input schema has 100% description coverage and already explains feature_id as the feature's number from feature_board or its cymetica.com link. The description adds no new parameter-level detail beyond implying a single feature, so the baseline 3 is appropriate.

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 clearly specifies the resource: one feature's aggregate bidding numbers, including the ET10 bid, bidder count, highest bid, open status, and minimum. It also distinguishes itself by explicitly stating 'Never who bid what,' which separates it from per-bidder or per-account tools like feature_my_bids.

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 intended use is implied: call this when you need aggregate bidding numbers for a single feature. The 'Never who bid what' line warns against using it for bidder-level details, but no specific alternative tool is named and there are no explicit when-to-use or when-not-to-use conditions.

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