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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds meaningful extras beyond that: it is free with no account, inputs must be public and non-personal, and the response includes the quoted rule, a timestamp and a signature. It stops short of describing latency or rate limits.

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?

Dense but well front-loaded: the trigger condition and the two arguments come first, followed by sources and return values. The parenthetical restatement of the title is slightly redundant, but every other clause earns its place.

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 compensates by enumerating the four possible verdicts and the accompanying evidence (quoted rule, time, signature). Combined with the annotations and a fully documented schema, an agent has everything needed to call and interpret this tool.

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%, so the schema already documents url, agent and user_agent in detail, giving a baseline of 3. The description adds value by indicating the required input shape and the public/non-personal constraint on the URL, plus the default '*' behavior context for the agent token.

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 verb+resource ('check permission before your agent fetches a page') and enumerates exactly what sources it consults (robots.txt per RFC 9309, AI-preference lines, RSL, tdmrep.json, llms.txt) and what it returns (ALLOWED/DISALLOWED/NO_RULE/UNKNOWN). This is clearly distinguishable from siblings like gaip_watch_register or gaip_diagnose_integration_failure.

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?

'Use this before your agent fetches a page' gives an explicit trigger condition, which is strong usage guidance. It does not name alternatives or state when NOT to use it, but the pre-fetch check framing is unambiguous enough that an agent knows the context.

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