List Agent Skills

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

Beyond the annotations, the description discloses that only loaded skills are listed, that skill markdown bodies are not returned, and that authentication is gated by tool policy. It also explicitly states 'Read-only', consistent with the readOnlyHint annotation.

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 compact and front-loads the primary purpose, then adds usage guidance, exclusions, and auth in a logical sequence. Every sentence earns its place without repetition.

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 zero-parameter, read-only listing tool with an output schema, the description fully covers what the tool returns, how to use it, what it does not return, and how to get the missing content. No critical context is missing.

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?

This tool has zero parameters, so the schema already fully covers the parameter surface. The description appropriately adds no parameter information, matching the baseline of 4 for parameterless tools.

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 states a specific action ('List loaded Agent Skills') and identifies the exact fields returned: name, skills:// URI, description, and tags. It clearly distinguishes itself from the sibling a2a_card tool and from fetching skill markdown bodies.

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?

It explicitly says when to use the tool ('Use to find skill resources to read next'), what it does not do ('Does not return skill markdown bodies'), and names the alternative ('fetch those via the skills://{name} resource'). It also warns against using it for the A2A card, leaving no ambiguity.

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