accessibility_check

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

With no annotations, the description carries the full burden and does so: it discloses pricing ($0.015 USDC), p99 latency (20s), a partial-refund rule ('Not charged when the page cannot be loaded'), the automated-coverage limit (~a third of barriers), and a detailed picture of the returned grade, impact ordering, selectors and fix hints.

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?

Front-loaded with the core purpose, then tiers of detail. The long parenthetical rule list and the standards sentence are dense but each carries selection-relevant information; nothing is padding, though the description is on the verbose side.

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 and no annotations, the description fully picks up the slack: it explains what the audit returns, how results are graded and sorted, the coverage limitation, billing conditions and cost. An agent has everything needed to call it and interpret results.

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 both parameters are already documented in the schema. The description restates the mobile mode as a '390 px phone viewport', adding marginal colour beyond the schema's '390x844 vs 1280x800'. Baseline 3 is appropriate when the schema does the heavy lifting.

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 and resource ('Automated web accessibility audit of a page in a real browser with axe-core') and grounds it in named standards (WCAG 2.2 AA, EN 301 549, EAA, BFSG, BaFG). This clearly distinguishes it from neighbours like seo_meta, site_audit, privacy_check and image_alt_text.

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?

Strong when-to-use framing ('For the EU Accessibility Act (EAA), the German BFSG ... and Austrian BaFG') and an explicit scope caveat ('a screening, not a certification and not legal advice'). It stops short of naming an alternative sibling or a when-not-to-use condition, so it is clear context without explicit routing.

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