validation.w3c.validate_pages.v1

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It doesn't state what the tool returns (output schema exists but the description doesn't mention it), whether there are network dependencies on the W3C service, rate limits, or what happens on validation failure. For a tool that makes an external network call to a validation service, this is a meaningful gap.

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 a single, efficient sentence that's easy to parse. It's appropriately short for a validation tool with simple parameters. However, it could have added a bit more value in the same length (e.g., mentioning it's non-destructive, or the level default behavior).

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?

There is an output schema and the parameters are relatively simple, but as a network-dependent external service call with multiple similar sibling tools, the description should clarify the distinguishing scenario (raw HTML vs live URLs) and what the tool does after validation (just reports? Does it optionally fix warnings?). It's adequate for basic use but incomplete for ambiguity resolution.

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 0%, so the description must compensate. However, the schema itself is fairly self-documenting: pages (array of objects with html and url), level (enum error/warning). The description mentions 'raw HTML pages' which maps to the pages.html field. The level parameter is not explained in the description but its enum values are self-explanatory. Does not fully compensate for 0% coverage but the schema does decent work on its own.

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 states the tool validates raw HTML pages through the W3C Nu Validator, which is specific enough (verb=validate, resource=raw HTML pages, through=Nu Validator). However, it doesn't distinguish from sibling tools like validate_urls_raw.v1 or validate_and_recheck.v1, which presumably also involve W3C validation. The scope (raw HTML vs URLs) is a differentiator, but the description doesn't explicitly call it out.

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?

There is no guidance on when to use this tool vs alternatives. Given siblings like validation.w3c.validate_urls_raw.v1, validation.w3c.validate_and_recheck.v1, and validation.w3c.autofix_safe.v1, the agent needs to know that this tool is for raw HTML content (not URLs) and that it's validation-only (no recheck, no autofix). None of this is stated.

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