skill_list

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

Annotations already cover the safety profile (readOnly, idempotent, closed-world), so the description's value-add is its disclosure of failure behavior: unreadable entries are reported so 'an empty list is never a mystery.' That is genuinely useful operational context beyond the annotations, though it doesn't mention ordering, limits, or staleness.

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?

Two sentences, both front-loaded and information-dense: the first enumerates the returned fields, the second covers the failure mode. No filler or restatement of the tool name.

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?

With no output schema and no parameters, the description carries the full burden and discharges it by naming the exact fields returned and the error-reporting behavior. An agent knows what it gets back and how to interpret an empty response.

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 takes zero parameters, so there is nothing to document beyond the schema; baseline 4 applies. The description instead spends its budget on the return shape, which is the relevant semantic content here.

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?

Names a specific verb and resource ('List every Agent Skill this server found') and enumerates exactly what the listing contains: name, description, when-to-use, bundled file count, and executable scripts. It also implicitly differentiates itself from skill_run by noting scripts 'may be executed with skill_run', making the read-vs-execute split with siblings clear.

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?

Pointing at skill_run for execution implies this is the discovery step before loading or running a skill, so usage is inferable. However, it never states when to call this versus skill_load or skill_file, nor any conditions or exclusions, leaving the routing to inference.

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