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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior. The description adds important behavioral detail beyond annotations: authentication/plan gating for premium fields and a specific fallback response ('locked' with 'upgradeUrl') when content is restricted.

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 tightly written sentences, front-loaded with what the tool does, followed by access and gating information. Every sentence earns its place with no redundancy.

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?

Given a simple one-parameter fetch, full schema coverage, an output schema, and annotations covering safety, the description adds the crucial missing pieces: public vs premium access and the locked-response behavior. Nothing an agent needs to call it correctly is absent.

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%, and the single parameter 'id' is fully documented in the schema (including that it comes from 'search' or a URL). The description adds no new parameter-level syntax or constraints, so the baseline of 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 ('Lee') and resource ('ficha de subasta') and the lookup key ('por id'), which distinguishes it from search-oriented siblings. It also enumerates the returned fields, making the tool's scope clear without opening the 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?

Provides clear context: public read with no account, but premium fields require an account and Pro plan or higher. It does not explicitly name alternative tools or state when not to use it, but the id-based retrieval context is sufficient for correct selection.

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