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

Annotations already mark this as read-only and idempotent, so the description's main burden is to add useful context. It does so by disclosing that results are estimates, that output is JSON, that the call has a £0.01 cost, and that it references EU AI Act Art. 50 and schema.org. This goes beyond the structured annotations without contradicting them.

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 four short sentences with no filler. 'Returns JSON visibility metrics' is slightly redundant with the opening clause and the output schema, but the compliance and cost statements are distinct and valuable, so the overall structure is efficient and front-loaded.

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?

This is a low-complexity, single-parameter read tool. The description states what metrics are returned, labels the estimates, gives the JSON return shape, and adds operational context (cost, compliance). Combined with the read-only annotations and the output schema, nothing an agent needs in order to invoke it correctly is missing.

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 single 'url' parameter is already clearly documented as the merchant URL whose metrics should be returned. The description merely repeats 'merchant URL' and adds no format, normalization, or edge-case detail, so it adds no semantic value beyond 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 opens with a specific action ('Retrieve') and a specific resource ('estimated LLM mention rate and GEO score for a merchant URL'), and names the return type. The named metrics make it distinguishable from sibling tools like get_agent_maturity or run_geo_audit, which focus on different concepts.

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 tool's intended use is implied by 'for a merchant URL' and 'Retrieve estimated LLM mention rate and GEO score', but the description gives no explicit condition, no exclusions, and no pointers to an alternative tool. It does not help an agent decide between this and the many similar-looking sibling tools.

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