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

With no annotations, the description does much of the behavioral work: it says robots.txt is fetched live, explains the longest-match rule, names default user agents, and describes the returned decision, deciding rule, and crawl delay. It does not cover failure behavior when robots.txt is missing or unreachable, so it is strong but not complete.

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 description is three tight sentences, front-loads the core question, then adds the matching rule and return details without filler. The parenthetical agent list is dense but useful.

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?

For a two-parameter check with no output schema, the description explains the decision outcome, the deciding rule, and crawl delay, which is sufficient for an agent to understand what calling the tool yields. The courtesy-check caveat also sets appropriate expectations.

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 already 100%, so the baseline is 3. The description adds real meaning by specifying that user_agent defaults to '*' plus named AI crawler agents, which is not captured in the schema.

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 states a specific boolean question and mechanism: it checks whether robots.txt allows fetching the exact URL, fetches the live robots.txt, and applies longest-match rules. This clearly distinguishes it from site-level siblings such as check_site and list_sites without needing 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?

The phrase 'this exact URL' and the disclaimer 'courtesy check, not a legal opinion' give clear usage context. However, the description does not explicitly say when to use this instead of a sibling like check_site, so it stops short of full alternative routing guidance.

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