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

Annotations cover the safety profile (readOnly, idempotent, non-destructive, closed-world), but the description adds genuinely useful behavior beyond them: the tool is public with no account, several sections (scoring, veredicto, cargas, ROI, valoración, intervinientes) are tier-gated behind Pro, and gated content is signaled via 'locked' plus 'upgradeUrl' rather than erroring. That partial-result contract is exactly the kind of detail annotations cannot 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 dense sentences that lead with the resource and lookup keys before the access/tier caveat. Every clause carries information (fields returned, public access, Pro gating, locked contract), with no filler. It is packed but not padded.

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 an output schema present and annotations covering safety, the description only needs to add access, identification and gating context — and it does all three. An agent knows how to identify the auction, what it may get back, and what a gated response looks like, so nothing material 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 description coverage is 100%, so the meaning, pattern and max length of id, url and boe_id are already documented — including that boe_id 'devuelve todos los lotes'. The description restates the 10-character id form and lists the same lookup modes without adding format, precedence, or whether at least one parameter must be supplied. 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 concrete resource (ficha pública de una subasta del BOE) and the three ways to identify it (10-char id, app.subastech.com URL, SUB- BOE id), then enumerates the returned fields. It implicitly separates itself from paid siblings like analisis_subasta by declaring 'pública, sin cuenta' versus the Pro-only scoring/veredicto. No sibling is named outright, but an agent can distinguish it without opening other schemas.

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?

Gives real usage context: no account required, lookup by id/url/boe_id, and the behavior when a section is gated ('se devuelve locked con upgradeUrl'). However it never states when to prefer this over buscar_subastas, buscar_por_codigo or analisis_subasta, so routing between siblings is left to inference.

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