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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint and destructiveHint=false, so safety is covered. The description adds genuinely new behavior: the payload can be very large, results are cached for 24h, and content is capped at 20 linked pages. It does not say what happens on failure (non-existent llms.txt, non-HTML targets), which keeps it from a 5.

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?

Three tight sentences, front-loaded with the core action and payload, followed by the size warning and cache note. No filler and no repetition of the title.

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 no output schema, the description carries the burden of describing return values, and it does: index plus up to 20 pages of Markdown, the document itself, or a video transcript. Size and caching behavior round out what an agent needs before invoking it.

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% — both url (with example forms and optional scheme) and fresh (ignore 24h cache) are already documented in the schema. The description reinforces what the link may point to but adds no syntax or constraint beyond that, so the 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 (get llms-full.txt for a link) and then defines exactly what that payload contains: the llms.txt index plus full Markdown of up to 20 linked pages, or the page/document itself, or a video description plus timestamped transcript. This level of specificity makes it unmistakable against the sibling llms_txt.

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?

Explicitly routes the agent: 'prefer llms_txt when you only need to find pages,' combined with the warning that the result 'can be large.' The condition that selects the cheaper alternative is stated outright, so an agent does not have to infer it from the names.

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