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

Adds real context beyond the annotations: determinism, no network/state, and per-call limits (1 s, result up to 1 MB). One flaw: it says JSON input is capped at 64 KB while the schema declares data maxLength of 1,048,576 (1 MB), a contradictory bound that could make an agent over-constrain input.

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?

Front-loaded with the definition and labeled sections (Cuándo / No para / Efectos / Límites) that make scanning easy. Docked one point because the entire content is duplicated in Spanish and English, roughly doubling length without adding information.

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?

Safety is covered by annotations, return shape by the output schema, and inputs by full schema coverage, so the description only needed usage and limits — which it supplies. The only gap is the input-size limit conflicting with the schema's maxLength.

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 both enums (input_encoding, output_encoding) are fully documented in the schema, so the baseline applies. The phrase 'texto o unos bytes' hints that string input may be interpreted as bytes, but no encoding syntax or format guidance is added.

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 and algorithm ('Calcula el resumen SHA3-256 (FIPS 202)') and immediately differentiates it from the closest sibling by naming the padding difference vs Ethereum keccak256. An agent can pick between hash-sha3-256 and hash-keccak256 without opening either 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?

Has explicit 'Cuándo' (compare content, match a published checksum) and 'No para' clauses with the alternative tool named (hash-keccak256). When-to-use and when-not-to-use are both spelled out rather than implied.

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