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

readOnlyHint=true already marks this as a safe read, but the description adds genuinely new behavioral context: that access is 'Free, no API token needed,' which tells the agent authentication isn't a barrier. It stops short of describing result volume, ranking, or pagination.

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?

Two tight sentences with no filler, and the core purpose is front-loaded before the clarifying aside. Minor repetition of 'Pandus' and a slightly nested parenthetical keep it from a clean 5.

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 search tool with no output schema and full schema coverage, the description is largely sufficient. It could say more about what a result looks like or how it relates to the explain_* siblings, but nothing critical to correct invocation 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%, so the schema already documents both query and locale. The description's enumeration of query forms and the 1.4.3 example merely restate what the schema (and its description) already say, so the baseline of 3 applies.

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 (Searches) and resource (Pandus library of accessibility rule cards), and clarifies what those cards actually are (axe-core rules explained for business owners). It does not, however, name the sibling tools explain_rule or explain_wcag_criterion to draw a boundary between searching and explaining.

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: the accepted query forms (words, axe rule id, WCAG criterion) suggest when to reach for it. There is no explicit when-not or named alternative, even though explain_rule and explain_wcag_criterion are obvious candidates for routing.

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