robots_txt_check

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

Annotations declare openWorldHint=true and destructiveHint=false, and the description meaningfully extends this by disclosing the Googlebot user-agent emulation, the 500 KiB evaluation threshold, and the side effect of persisting results to history (consistent with readOnlyHint=false). It stops short of noting auth requirements, rate limiting, or what happens for a missing/erroring robots.txt, which would matter for a remote fetch.

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?

One front-loaded sentence with the action first and the returned artifacts following as a compact enumeration. Every clause maps to a real output; nothing redundant or padded.

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?

There is no output schema, so the description usefully enumerates what comes back, including the size-limit check and Google's own interpretation. For a one-parameter read-plus-history tool this is close to complete; only edge-case behavior (robots.txt missing, 4xx/5xx, blocked fetch) is left unstated.

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?

With a single parameter at 100% schema coverage, the schema already documents that host, URL, or sc-domain property is accepted. The description adds no formatting or normalization guidance beyond that, so the baseline of 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 ('Fetch robots.txt like Googlebot') and enumerates the concrete outputs (status, size vs 500 KiB, groups, Googlebot rules, sitemaps, syntax warnings, diff). It does not, however, distinguish itself from the closely named sibling robots_txt_check_property, and its mention of 'diff' and 'history' overlaps conceptually with robots_txt_diff and robots_txt_history.

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?

Usage is only implied: an agent can infer this is for validating crawlability of robots.txt as Googlebot, versus robots_txt_test (live rule testing) or robots_txt_watch (ongoing monitoring). There is no explicit when-to-use statement, no exclusions, and no sibling is named as an alternative.

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