Validate local CSS

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

Annotations already carry the safety profile (readOnlyHint, openWorldHint, idempotentHint, destructiveHint=false), and the description adds genuinely useful context beyond them: the specific external destination (W3C Jigsaw), a 'bounded' size constraint, and the privacy implication that local file content is sent to a third party. It does not contradict the annotations; openWorldHint aligns with the external send.

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 sentences with zero waste; the core function is front-loaded in the first sentence and the critical security constraint lands in the second. Every word 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?

For a single-parameter tool with a full schema, strong annotations, and an output schema, the definition is nearly complete: it names the external service, flags the sharing boundary, and scopes the input. The only real gaps are that 'bounded' is unspecified as to the actual size cap, and there is no routing to sibling tools for related but different validations.

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%, with filePath already described as 'Absolute or workspace-relative path to a CSS file.' The description adds only marginal qualifiers ('bounded', 'local') that do not substantially enrich parameter understanding, so the baseline of 3 applies.

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: 'Reads a bounded local CSS file and sends it to the W3C Jigsaw CSS Validator.' The domain (CSS validation) and input type (local CSS) clearly distinguish it from siblings like html.local, seo.metadata, and links.broken, so an agent can tell it apart without opening schemas.

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 implies usage context (validating a local CSS file) and adds an authorization constraint ('Use only files the user is authorized to share'), but it never states when to prefer this over alternatives or when not to use it. No explicit exclusions or sibling routing are provided.

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