list_skill_files

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

With no annotations, the description must carry the full behavioral burden. It conveys that the tool is a read-only listing operation and that subdirectory filtering is available, but it does not mention potential side effects, ordering, hidden-file inclusion, or error behavior. Some behavioral context is added beyond the tool name (listing 'reference files, scripts, or resources' ), but it is sparse.

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, front-loaded with the core verb-resource and followed by a clear directive on a parameter. No unnecessary words or redundancy.

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 2-parameter tool with an output schema present, the description covers the main use case and parameter guidance. It doesn't need to describe return values (output schema exists). Minor gaps like recursion or sorting behavior are acceptable for this simplicity, and the available context signals are sufficient.

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 schema describes only parameter names given 0% coverage, so the description must compensate. It explicitly explains the optional subdirectory parameter with examples ('references' or 'scripts'), but it leaves skill_name to implicit understanding from the phrase 'a skill's directory'. This partially compensates but not fully.

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 action ('List files') and the resource ('in a skill's directory'), and explains it's for discovery of reference files, scripts, or resources. This separates it from sibling tools like read_skill_file (reads a specific file) and fetch_resource (retrieves a resource), making the purpose unambiguous.

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 phrase 'Use this to discover...' gives explicit context for when this tool is appropriate. It doesn't explicitly state when not to use it or name alternatives, but the listing intent is clear, so a strong 'when' cue is present.

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