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

Annotations already declare readOnly, idempotent, non-destructive and openWorld=false, so the offline/no-state claims are largely restatements. The description does add genuinely new operational context the annotations cannot convey: 64 KB input cap, 1 s per call, 1 MB result cap. It also clarifies the scope limit (does not check balances or ownership).

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?

Content is front-loaded and every claim is substantive, but the entire block is duplicated verbatim in Spanish and English, and the EN section is truncated mid-sentence with a meta-reference ("[EN completo / full EN: inputSchema.description]"). Roughly half the length is redundancy.

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-param offline validator with an output schema, the description covers purpose, routing, determinism and resource limits — enough to invoke correctly. The remaining gap is failure behavior (does an invalid address throw or return a negative result), which the output schema may or may not cover.

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 an example, so the baseline is 3. The description goes slightly beyond by specifying the underlying semantics — a 20-byte hex address — which explains why the schema's maxLength is 64 rather than the expected 42 characters, useful disambiguation for a single-param tool.

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 ("Valida una dirección EVM") plus the exact check performed (20-byte hex format + EIP-55 checksum) and the return value (checksummed form). It explicitly names a sibling it is not (bitcoin-address-validate), so the agent can route without opening 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?

"Cuándo" gives the trigger condition (verifying format and check digit offline before use) and "No para" names the exclusion with the alternative tool (bitcoin-address-validate for Base58Check). Both the positive and negative routing decisions are explicit.

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