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

Beyond the annotations (readOnly, idempotent, closed-world), the description adds determinism guarantees and concrete operational limits: 64 KB JSON input, 1 s per call, 1 MB result. These quota/timeout constraints are not derivable from the annotation block and materially affect invocation planning.

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 with purpose, then labeled fields (Cuándo / No para / Efectos / Límites) that scan quickly. The full Spanish-then-English duplication roughly doubles the text, which is a deliberate bilingual pattern rather than waste, but it slightly dilutes density.

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-value documentation is not needed. The description covers purpose, alternatives, side effects, determinism, and size/time limits — everything required to call a pure hash function 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 description coverage is 100% and both optional parameters carry enum values with defaults, so the schema fully documents input_encoding and output_encoding. The description adds no syntax or format guidance beyond the schema, which is acceptable but not additive; 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 ('Computes the RIPEMD-160 digest (160-bit)') and adds the concrete use domain ('used inside Bitcoin HASH160'). It explicitly distinguishes itself from the sibling hash-sha256, so an agent can select it without opening a 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?

Contains explicit 'When' guidance ('an exact digest of given text or bytes is needed, e.g. to compare content or match a published checksum') and an explicit 'Not for' clause naming the alternative tool. Both the positive and negative selection conditions are stated.

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