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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=true, so repeating 'zero state mutation' earns nothing. However, the description adds genuinely useful facts not in the annotations: public unauthenticated access and a concrete rate limit of 60 requests/min per IP, plus a sketch of the return shape. That is real added context for an open-world network call.

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?

Purpose is front-loaded and the sentence ordering (purpose → usage → params → side effects → returns) is sensible. But the 'when you specifically need to execute audit_domain on AEO Auditor (aeoauditing.com)' clause and the 'Strictly read-only, idempotent... zero state mutation' clause largely duplicate the annotations and the tool name, so several sentences do not fully earn their 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?

For a single-parameter read-only audit with no output schema, the description covers purpose, the sibling boundary, the required parameter, auth/rate-limit constraints, and the shape of the response. What is thin is depth-of-audit and failure behavior (e.g. what happens on an unreachable domain or how many checks run), which for an open-world network tool is a minor remaining gap.

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?

There is only one parameter and schema description coverage is 100%, with the schema already giving examples ('stripe.com' or 'https://stripe.com'). The description only restates 'url (required)', adding no further semantics such as whether subpaths/schemes are honored or normalization behavior, so 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 first sentence gives a concrete verb ('Execute a ... diagnostic audit') and a specific resource ('any domain or URL'), enumerating the audit dimensions (AEO, GEO, JSON-LD Schema AST, /llms.txt readiness). It names both siblings, so the tool is distinguishable, though the later line 'Call this tool when you specifically need to execute audit_domain' is a tautological restatement that adds nothing.

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 description has an explicit 'when to use' / 'do NOT use' frame and names both alternatives, but the routing content is hollow: 'use get_domain_benchmark or validate_robots_txt for their respective operations' never says which condition selects which sibling, and 'when you specifically need to execute audit_domain' is circular. The agent must infer the boundaries from the audit dimensions listed in sentence one.

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