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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, yet the description still adds real value: no network access, no stored state, determinism, and explicit limits (1 s per call, result up to 1 MB). One flaw: it claims 'JSON input up to 64 KB' while the schema's markdown maxLength is 1 MB, an internal inconsistency the agent must resolve.

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?

Well front-loaded and cleanly sectioned (Cuándo / No para / Efectos / Determinista / Límites), but the entire Spanish block is restated in English and again inside inputSchema.description, so a large share of the text is duplication rather than new information.

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?

With an output schema present and annotations covering safety, the description supplies what structured fields cannot: sibling exclusion, determinism, and size/time limits. It is nearly complete for a single-parameter read-only tool, held back only by the 64 KB vs 1 MB limit mismatch.

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 the single 'markdown' parameter carries a worked example, so the schema already does the work. The description adds nothing about the parameter itself — the 'flagging relative and non-http(s) links' detail describes output, not input — 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 set: lists inline links, images, reference definitions and bare URLs in Markdown, with text, target and flags for relative/non-http(s) links. It explicitly names the sibling it is not (html-links-extract), so an agent can separate the two 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' clause names the alternative (html-links-extract) and the condition that selects it, which is the key routing decision here. The 'Cuándo' list, however, is generic boilerplate (HTTP headers, tokens, versions, IP ranges, agent-readiness files) rather than markdown-link-specific triggers, so the positive guidance is weaker than the negative.

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