list_skills

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 explains the scanning scope (project-level and user-level directories, SKILL.md files) and the return format (JSON array with name, description, path). This goes beyond a simple 'list' and gives useful operational detail, though it does not cover edge cases like missing directories.

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: the first states the core purpose, the second adds scanning and return details. It is front-loaded, concise, and every word contributes. No redundant or vague language.

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 low-complexity list tool with one optional parameter and an output schema, the description is complete. It covers what action is performed, where skills are scanned, and what the return format is. It does not explain the concept of 'agent skills,' but that is likely assumed context. Sibling differentiation is not addressed but is not necessary for completeness.

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 for project_roots has a 100% coverage description, fully explaining the parameter's behavior. The tool description does not mention parameters, but the schema already provides the necessary semantic detail, so the baseline of 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 with a specific verb and resource: 'List all available agent skills with their names and descriptions.' It distinguishes from siblings (activate_skill, read_skill_file) by focusing on enumeration, not activation or file reading.

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 when to use the tool (to list available skills) and provides context about scanning project and user directories, but it does not explicitly mention alternatives or exclusions (e.g., 'use read_skill_file to view contents'). The usage is clear but not directly contrasted with sibling tools.

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