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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false. The description adds meaningful behavioral context beyond that: the tool is public and requires no account, some fields are gated behind a paid plan, and locked fields are returned as `locked` with an `upgradeUrl`. This is valuable for setting agent expectations about degraded responses and paywall behavior. The write-free, idempotent behavior is consistent with the annotations, and the description's claims do not contradict them.

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?

The description is compact but information-dense: two sentences cover input forms, returned fields, public access, paywall gating, and locked responses. It is front-loaded with the core purpose and input forms before diving into plan limitations. There is no filler or repetition of schema text.

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 the presence of an output schema that can describe return values, the description covers the remaining contextual essentials: how to address the resource, what data is public, what requires a plan, and how locked fields behave. Input parameters are fully documented in the schema, so an agent has everything needed to invoke it correctly. The tool's complexity is moderate, and the description plus schema plus annotations form a complete picture.

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%: each parameter (id, url, boe_id) has its own schema description explaining format and semantics. The tool description adds the functional context of how the inputs relate to the resource: URL from app.subastech.com and BOE identifiers with the SUB- prefix. No parameters have enums and required is 0, which the description partly explains by saying the tool accepts 'por identificador, URL o identificador BOE,' implying any one is sufficient. The description does not add significant syntax beyond the schema except the BOE-ID-returns-all-lots note, 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 states that this tool retrieves a public auction sheet from BOE by identifier, URL, or BOE ID, and lists the specific fields returned (address, values, dates, result, lots, summary). It is immediately distinguished from siblings like buscar_subastas or analisis_subasta because it is a single-record ficha by identifier rather than a search or analysis. The title 'Ficha de una subasta' reinforces the resource but the description adds the specific input forms and output coverage.

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 description states the tool is public and requires no account, and it explicitly says which fields are available without login versus which require a plan. It also names the input formats (10-character ID, app.subastech.com URL, BOE identifier) and notes that BOE ID returns all lots. It does not explicitly name sibling alternatives or contrast with search tools, but for a lookup-by-identifier tool the usage context is clear enough. The clear public/no-account statement helps an agent decide when to use this tool over ones requiring auth.

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