analyze_url

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

With no annotations, the description carries the full burden of behavioral disclosure. It does reveal meaningful configurable details via the bracket notation: default engine ('axe'), WCAG version ('2.1_AA'), and viewport size ('1280x1024'). However, it does not disclose potential side effects (e.g., network requests), error handling, or any rate limits, and the return format is only vaguely described as 'detailed violation reports'. This is useful but not comprehensive.

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?

The description is extremely concise: one sentence plus a compact bracket. It conveys the core purpose and key configuration details without wasted words. The front-loaded structure immediately identifies the action and resource, and the bracket adds valuable context in a structured format. Every element 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?

Given that there is no output schema and no annotations, the description must cover more ground. It adequately explains the tool's purpose and key parameters, but it omits guidance on when to choose this tool over siblings and what the response format looks like beyond 'detailed violation reports'. This is a common gap for tools with siblings, making the description sufficient for basic invocation but not fully complete for an autonomous agent.

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?

The input schema provides 100% coverage for all three parameters, with descriptions for 'url', 'tags', and 'engine'. The tool description does not add additional parameter semantics beyond what the schema already provides. Since the schema is fully descriptive, the baseline score of 3 is appropriate; the description offers no extra value for parameters.

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?

The description clearly states the tool's function: 'Run accessibility tests on a URL and return detailed violation reports.' The verb 'Run' and resource 'URL' are specific, and the bracket notation adds useful context about engine and WCAG version. However, it does not explicitly distinguish itself from the sibling tool 'analyze_url_json', which likely provides the same accessibility tests in a different output format, so it misses an opportunity for full differentiation.

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 description provides no explicit guidance on when to use this tool versus alternatives. It does not mention that 'analyze_html' should be used for HTML input, or that 'analyze_url_json' might be preferred for JSON output. The context is clear for basic use, but no exclusions or alternative recommendations are given, leaving the agent without decision support.

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