validate_skill

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

Annotations already cover readOnly/idempotent/non-destructive safety, but the description adds non-obvious behavior: no project init needed, and the crucial caveat that a successful tool envelope does not mean the skill is valid — the report's errors and warnings must be inspected. That is exactly the kind of semantic warning annotations cannot carry.

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?

Four sentences, all load-bearing, with the operation stated first and prerequisites, alternatives, and the report caveat following in priority order. Slightly dense but no filler sentences.

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 read-only validation tool with an output schema, the description covers everything an agent needs: supported inputs, prerequisites, sibling boundaries, and how to interpret the returned report versus the envelope status.

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 the baseline is 3. The description restates that an ID/name or path is accepted, which mildly reinforces but does not extend what the schema already documents, and the optional scope parameter is left entirely to the schema.

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?

"Validate a draft, registered canonical skill, or local skill file/directory" names a specific verb and enumerates the three input forms it accepts, immediately separating it from sibling tools like publish_skill and get_skill_detail. The added constraint "without publishing or changing skill content" pins down the scope of the operation.

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?

Gives explicit timing ("before publish_skill or after editing a skill") and names an alternative ("get_skill_detail reads registered metadata") so the agent knows which sibling handles the adjacent task. It also notes that project initialization is not required at this interface, removing a common false prerequisite.

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