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

Annotations already declare readOnly, openWorld=false, idempotent and non-destructive, so 'solo lectura, sin red, sin estado guardado' is largely restatement. The description does add real value with determinism and a 1 s per-call limit, but the stated '64 KB' input limit conflicts with the schema's maxLength of 524288 characters, which undermines trust in the stated bounds.

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?

Purpose and exclusions are front-loaded and the format spec is tight. But the generic 'Cuándo' enumeration is filler that does not apply to this tool, and the full ES description is duplicated again in the schema's description field, inflating the payload without adding 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?

An output schema exists, so return values need not be explained, and annotations carry the safety profile. The description covers the format being validated, the exclusion, determinism and time limits — enough to call it correctly; only the mismatched size limit and the off-topic 'when' clause keep it short of complete.

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 single parameter is documented, so the baseline is 3. The description goes further by spelling out the expected shape of the content (one H1 first, optional > summary, H2 sections with '- [name](url): notes' lists, optional 'Optional' section), which tells an agent what valid input looks like beyond 'llms.txt content (string)'.

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 ('Revisa un llms.txt según el formato de llmstxt.org') and enumerates the checked elements (H1, resumen, H2 con listas de enlaces), plus what it reports (errores, advertencias, estructura). It explicitly separates itself from the closest sibling, agent-readiness-checklist.

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 and the condition that selects it, which is genuinely useful routing. However the 'Cuándo' clause is generic boilerplate ('una URL, una cabecera HTTP, un token, una versión, un rango de IP...') that does not describe this tool's actual use case and could push an agent toward it for unrelated parsing tasks.

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