Look up a WCAG 2.2 success criterion

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

With no annotations and no output schema, the description does real work: it enumerates the returned fields (level, principle, guideline, ADA Title II applicability, practical test, axe-core rules, W3C and Understanding links) and 'Search' implies a read-only operation. It omits pagination/limit behavior and result-count semantics, which are the remaining behavioral gaps.

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 dense sentences, each earning its place: the first covers input modes, the second covers output. Nothing is repeated from the schema and the search capability is 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?

For a read-only lookup tool with no annotations and no output schema, the description covers inputs and return contents well enough to call it correctly. The only shortfall is unexplained behavior for the limit and level filters.

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 33%: only 'query' is documented in the schema, and the description usefully extends it with axe-core rule names and concrete examples. However, the 'level' enum and especially the 'limit' parameter (caps results at 20) receive no explanation in either place, so the description only partly compensates for the coverage gap.

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 (search) and a precisely scoped resource (the 87 WCAG 2.2 success criteria), plus the exact matching modes: number, name, keyword, axe-core rule. Siblings like audit_html_snippet and get_verified_fix_example are clearly different operations, so no disambiguation is needed.

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 lookup modes imply when the tool is useful, but there is no explicit statement of when to use it versus siblings (e.g., before auditing a snippet, or to resolve a rule id found by audit_html_snippet) and no exclusions. Usage is inferable rather than stated.

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