List Skills

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

Annotations already declare readOnlyHint and idempotentHint, so the safe read-only nature is known. The description adds concrete behavioral context by listing the return fields (name, description, source, bundled files), going beyond what annotations provide. It does not describe pagination or sorting, but for a zero-parameter list tool this is sufficient.

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 exceptionally concise: two sentences. The first sentence states the purpose and output fields, and the second directs to the sibling tool. No filler or redundant information, 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?

Given the tool's simplicity (zero parameters, no output schema), the description is complete. It lists the return fields explicitly and points to the related sibling read_skill for loading a skill. Nothing critical is missing for an agent to use this tool effectively.

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 tool has zero parameters, and the input schema is empty, so there is nothing to explain. Per the rubric, a baseline of 4 is appropriate when there are no parameters. The description does not need to add parameter details because none exist.

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.' It also specifies the output fields (name, description, source, bundled files), which distinguishes it from siblings like read_skill that load a single skill.

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 tells the agent when to use an alternative: 'Call read_skill to load one.' This implies that list_skills is for browsing/identifying skills, while read_skill is for loading a specific one, providing clear context and direct guidance.

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