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

Annotations already establish readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real behavioral context beyond that: the fallback to nearest sites when no market exists, and the ordering of rules by how far behind they are. It omits output shape limits and whether results are paginated or size-capped.

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?

One sentence, front-loaded with the core concept and then the return contents, with no filler. It is dense and slightly comma-heavy, but every clause adds information.

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 must describe return values and does so meaningfully (rank, median score, per-rule share vs market median and best site, ordered by gap). What remains thin is when to choose this rather than sibling market tools.

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% for the single 'site' parameter, and the description adds nothing beyond the schema's domain-format note. Baseline 3 applies since the schema already carries full parameter meaning.

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 resource and scope: a site benchmarked against its market, including rank, median score, and per-rule pass-rate comparisons. It never names or contrasts with adjacent siblings like mttr_markets, mttr_competitors, mttr_leaderboard or mttr_similar, so the agent cannot confidently disambiguate 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?

There is no explicit when-to-use guidance, no prerequisites, and no named alternative. The nearest-sites fallback is a behavioral detail, not a routing instruction, so an agent must infer when this tool beats mttr_markets or mttr_compare.

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