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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), yet the description still adds real behavioral context: nothing is written to the site, output is markdown for the owner to publish, no AI engines are queried, and no effect on AI Overviews is promised. The line "A public post is cited as the reason the draft exists" hints at an external side effect but is vague enough to leave the agent unsure what that post is.

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 and trigger are front-loaded in the first two sentences, and the constraints follow in order of importance. Some sentences restate the same read-only guarantee ("Nothing is written to the site" alongside the no-side-effect framing), adding slight redundancy without hurting usability.

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 the description does not need to explain the markdown return value, and it correctly focuses on scope, side effects, and prohibitions. Coverage is strong for a single-parameter tool; the only soft spot is the unexplained "public post is cited" behavior.

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 parameter is fully documented in the schema with format examples and scope ("Only that site's public pages are read"). The description's "Pass the domain" 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?

The description names a specific verb and artifact ("Drafts an llms.txt") and its source ("from the site's own public pages"), which cleanly separates it from the sibling check_ai_instructions. An agent can tell what it produces without opening the 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?

It gives an explicit trigger ("Use this when the owner wants a draft AI instructions file to review") and an explicit exclusion ("Do not use it for private addresses or to collect contact details"). It stops short of naming the alternative sibling tool for the checking/validation case, so routing between generate and check is left to inference.

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