skills_list

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

The description discloses that it returns only metadata (~100 tokens per skill) and covers scope resolution order, which is valuable behavioral context. However, no annotations are provided, and the description does not mention whether this performs a read-only operation, whether it follows symlinks, or how errors are handled if the project root is invalid. Still, for a listing tool, the scope and return-type disclosure is adequate.

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 two sentences and front-loaded with the core purpose. It covers scope, return type, and the alternative tool in no more words than necessary. Every sentence 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 simple read-only discovery tool with one optional parameter and no output schema, the description is complete enough: it states scope, return size, and the next step (skill_load). The only minor gap is lack of detail about exact directory patterns, but that is not essential for an agent to select and invoke it correctly.

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?

There is one parameter, projectRoot, with 100% schema description coverage ('Project root (defaults to cwd)'). The tool description adds the context that the root is used to discover relevant skill directories, but the schema already explains the parameter well. Baseline 3 is appropriate.

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: discover SKILL.md skills from a project root with specific scope details (project vs personal). It also distinguishes itself from the sibling tool skill_load by noting this returns metadata only, which helps the agent understand the difference between listing and loading.

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 explicitly says when to use this tool: to discover skills visible from a project root, and explicitly tells the agent to use skill_load for the full body. This provides clear usage guidance and distinguishes it from the sibling skill_load without ambiguity.

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