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

The readOnlyHint and openWorldHint annotations already confirm the safety and scope profile, while the description adds useful behavioral detail: it derives location from address/phone numbers on the site's pages, uses semantic similarity, proximity, and similarity elsewhere, and reports score, pages, and inbound link counts. It does not contradict the annotations.

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 definition is front-loaded with the core concept and packs the relevant output categories into one sentence with no wasted sentences. It is dense and somewhat awkward in phrasing, but appropriately sized for the information conveyed.

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 carries the burden of explaining return values; it does so by naming the competitor categories and the per-result details (score, pages, and inbound link counts). Some ambiguity remains around scoring and ordering, but the definition is sufficient for an agent to understand what to expect.

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?

The input schema has 100% description coverage for the single site parameter, so the schema already explains that a domain such as example.com is expected. The description adds no further parameter-level semantics beyond implicitly referring to 'a site.'

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 clearly identifies the resource as a site's competitors and enumerates the categories returned: nearby semantic competitors, all nearby sites, and similar sites elsewhere. It is more specific than the title alone, but it does not explicitly distinguish itself from sibling tools such as mttr_similar or mttr_near.

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 explains what the tool returns but gives no explicit guidance on when to use it versus alternatives. With sibling tools like mttr_similar and mttr_near present, the lack of routing guidance is a clear gap.

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