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

Beyond the annotations, the description discloses substantial non-obvious behavior: resources are read from two sources, mismatches are routed to `resources_under_review` and must not be asserted as facts, and `resources_note` explains edge cases like SSL certificates and Windows hosting limits. This is exactly the kind of behavioral context an agent needs.

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 first sentence front-loads the core purpose and the subsequent paragraphs add necessary caveats about resource reconciliation and null semantics. It is longer than strictly necessary, but the extra detail is substantive rather than filler, and the structure is logical.

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?

The description covers input expectations, found and not-found return behavior, resource provenance, reconciliation edge cases, and the meaning of `resources_note`. With an output schema already present, it does not need to re-list return fields, and nothing essential for correct invocation 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?

The input schema only provides `name` with no description (0% schema coverage). The description compensates by explaining that the name must be exact and that a missing catalog entry returns null. It does not specify formatting or case sensitivity, but for a single string parameter this is reasonable and useful.

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 opens with 'Ficha completa de un plan por su nombre exacto', clearly stating that the tool returns a complete plan record when given an exact name. It specifies the content (prices, resources, source provenance, timestamps) and the null behavior, which distinguishes it from search-oriented siblings like search_products.

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 gives clear context: use this tool when you need a complete plan record by exact namehola. It also provides an important interpretive rule—if the plan is not in the catalog, null means it cannot be purchased. However, it does not explicitly name alternatives or state when not to use the tool, so it misses the top tier.

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