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

Annotations already cover safety (readOnly, idempotent, non-destructive, openWorld), so the description earns credit for going further: it enumerates exactly what the eight weighted signals evaluate and promises a concrete fix per failure. It omits operational behavior such as latency, rate limits, or failure handling for unreachable domains.

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?

Front-loads the verb and the payoff score, then parenthetically enumerates the signals; the 'Free, no account' fragment is a deliberate call-to-action. The signal list is long but each item is a distinct evaluation dimension rather than filler.

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 correctly compensates by describing the return (0-100 score, eight signals, per-failure fixes). Parameters and safety are covered elsewhere, leaving only error-path and timing behavior unspecified, which is a minor gap for a simple read-only scanner.

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 schema itself documents both params including accepted URL forms and the en/es enum, so the description adds nothing beyond it. Baseline 3 is appropriate when the schema carries the full parameter burden.

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 ('Scans a website') plus the concrete artifact produced ('AI Visibility Score (0-100)'), which no sibling produces. An agent can distinguish this scan-and-score tool from check_ai_recommendations and generate_llms_txt from the description alone.

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 implied by the purpose (scan a URL to get its AI visibility score) and the description usefully discloses a prerequisite condition ('Free, no account'), but it never states when to prefer this over the sibling tools or what to do with the result. No exclusions or routing guidance are given.

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