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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuinely new behavioral facts not in annotations: no network access, no stored state, deterministic output, and hard limits (64 KB input, 1 s per call, 1 MB result), which matter for planning large paginated Link headers.

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?

The purpose sentence is front-loaded and the template example is useful, but the Spanish and English blocks are near-duplicates and the generic 'When' enumeration mentions inputs (tokens, versions, HTML, agent files) irrelevant to Link header parsing, padding the definition.

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 values need no explanation; the description still covers purpose, the closest alternative, side effects, determinism and operational limits. For a low-complexity, two-parameter read-only parse tool, nothing needed for correct invocation is missing.

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%, so both parameters are already documented. The description adds only the semantic note that relative URLs are resolved against an optional base, which largely restates the schema's own "Base URL for relative links"; the baseline 3 is appropriate when the schema does the heavy lifting.

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: parses an HTTP Link header (RFC 8288) into URL + rel + other parameters, with the motivating use case of rel="next" pagination. It also names the sibling it is not (http-headers-parse), so an agent can distinguish it from the crowded set of header parsers 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?

The "No para / Not for" clause explicitly excludes the nearest alternative (http-headers-parse) with the distinguishing condition (raw header block → lowercase-keyed object). However, the positive "Cuándo/When" clause is generic boilerplate listing unrelated artifacts (tokens, versions, IP ranges, HTML/Markdown, agent files) rather than conditions specific to Link headers.

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