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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context beyond them: the check is instant/offline and, critically, cannot see other people's marks — flagging the false-negative limitation. It stops short of saying what the response contains.

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?

Three short sentences, no filler, with the core purpose and the scanned grounds front-loaded before the scope caveat. Every sentence earns its 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 two-parameter read-only tool with full schema coverage, the description gives enough to call it correctly. Without an output schema, it could have said what a verdict looks like (flags vs. pass/fail) or pointed to suggest_alternatives as the next step — a minor 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?

Both parameters are documented in the schema at 100% coverage, so the schema carries the load. The description adds no syntax, format, or tips for the optional 'description' field beyond what the schema already says. Baseline 3 is appropriate here.

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 concrete verb and resource (checks a mark) and enumerates the exact refusal grounds examined: descriptive, generic, surname, place name, famous brand. The line "It can't see other people's marks" implicitly separates it from search_marks, though no sibling is named explicitly.

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 only implied — an agent can infer this is a pre-filing sanity check, and the closing sentence hints at scope boundaries. There is no explicit when-to-use, no named alternative (e.g. suggest_alternatives, search_marks), and no statement of prerequisites or follow-up actions.

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