Audit a page for accessibility problems

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

Beyond the readOnlyHint/openWorldHint annotations it discloses the engine (axe-core), that execution happens in a real browser, the WCAG versions checked, and a credit cost per call, which is genuine added context. It omits things like expected runtime/timeouts or whether the audit covers only the given URL or linked pages.

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 with the core action, the output shape, and the cost, all front-loaded. No filler or restatement of the title.

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 does the necessary work by naming the return structure (violations grouped by severity with offending elements). Small gap: it doesn't clarify whether passing rules/incomplete checks are included or the shape of each finding.

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 only 50%: max_violations is documented in the schema itself and the description adds nothing about its default or cap semantics, while url has no schema description and is only implicitly explained by 'against a URL in a real browser'. Baseline 3 is appropriate since the schema does most of the work.

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 (run axe-core against a URL) plus the exact output (WCAG 2.0/2.1/2.2 violations by severity with responsible elements). The line 'returns structured findings rather than an image' explicitly separates it from the capture_screenshot and capture_pdf siblings.

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?

It implicitly routes the agent to this tool when actionable findings are needed instead of a visual artifact ('so you can act on them directly'), and the 'costs 1 credit per call' note gives a selection signal. It does not explicitly say when not to use it, nor position it against compare_pages.

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