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

Goes well beyond annotations by disclosing the 4-byte double-SHA-256 checksum verification, that the first byte is interpreted as version, determinism of output, and hard limits (64 KB JSON input, 1 s per call, 1 MB result). Read-only/no-network/no-stored-state is stated but is already covered by readOnlyHint and openWorldHint, so the added limits carry the score.

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?

Each language version is front-loaded and efficiently structured with labeled When/Not-for/Side-effects/Limits. However the full text is duplicated in Spanish and English, roughly doubling length without adding information; a tighter single-language-plus-gloss would score higher.

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?

An output schema exists so return shape needn't be explained, yet the description still notes payload plus version byte. With limits, determinism, and the encode alternative all covered, an agent has everything needed to call it correctly.

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 coverage is 100% with a single documented required parameter including an example, so the schema already does the work. The description adds nothing parameter-specific (e.g. no note on whitespace, length limits below the 4096-char schema cap, or what an invalid checksum yields), so the 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 specific verb+resource (decode Base58Check, verify checksum, return payload and version byte) and names the sibling it is not (base58check-encode). An agent can distinguish it from base58-decode and base58check-encode 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?

Explicit "Cuándo" and "No para" sections, with base58check-encode named as the alternative. Minor deduction: the When clause says bytes/text must be converted "a esta codificación, o desde ella", which half-describes the encode direction and muddies the boundary versus base58check-encode and base58-decode.

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