List Vault Directory

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds value beyond that by disclosing error messages ('Error: ... not found'), rate-limit behavior and the GITHUB_TOKEN tip, and the exact JSON return structure. While it repeats some annotation info, it contributes meaningful behavioral context.

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 organized into clear sections (Args, Returns, Examples, Error Handling) with a front-loaded purpose statement. Every sentence contributes: examples clarify usage, the 'Don't use when' routes to a sibling, and error handling preempts common failures. No fluff 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 list-directory tool with no output schema, the description provides everything an agent needs: the return format (JSON), error handling, rate-limit advice, and usage examples. It also differentiates from siblings. Open-world concerns like large results are partly addressed by the rate-limit note. Nothing critical 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?

Schema description coverage is 100%, so parameters are fully documented in the schema (defaults, descriptions, enum). The description repeats this information and adds usage examples ('governance' path) but does not introduce new semantic meaning not already in the schema. Baseline 3 is appropriate; the examples are marginal added value.

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 and resource: 'List the files and subdirectories at a given path in the canonical-vault repository'. It explicitly names the sibling tool it is not (vault_get_file) and provides usage examples that clarify the exact scope. This clearly distinguishes it from the other siblings.

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 gives explicit when-to-use examples ('What's in the governance directory?') and an explicit when-not-to-use condition ('Don't use when: You need the actual contents of a file (use vault_get_file instead)'). This is the clearest possible guidance, leaving nothing to inference.

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