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

Annotations already cover read-only, idempotent and closed-world, and the description reinforces them while adding genuinely new context: determinism, the 64 KB input cap, 1 s per-call budget and 1 MB result cap. It stops short of describing the output shape, but an output schema exists, so this is close to complete.

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?

Information is front-loaded—algorithm first, then when/not-for, then side effects and limits—and every sentence carries content. The cost is that the entire block is duplicated in Spanish and English, roughly doubling length for a single-language reader.

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?

For a one-parameter deterministic encoder with an output schema, this covers everything an agent needs: algorithm, when to use, the sibling alternative, safety profile, determinism and operational limits. Nothing material is left to inference.

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% and the schema already documents payload_hex, its pattern, max length and the 'including version byte' nuance. The description's note about 'including any version byte' adds emphasis but no new syntax or format information, so 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 and resource plus the exact algorithm (append 4 bytes of double SHA-256, then Base58), so the agent knows precisely which transformation happens. It also distinguishes itself from base58check-decode and, implicitly, from plain base58-encode by naming the checksum step.

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' plus an explicit 'No para' clause naming base58check-decode as the alternative for decoding/verifying checksums. Both the use case and the exclusion route the agent unambiguously.

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