list_allowed_directories

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

Annotations already declare readOnlyHint=true, and the description aligns by saying 'Returns the list.' It adds context beyond annotations by noting that subdirectories are also accessible and explaining the meaning of an empty list, which is helpful behavioral/config guidance without contradiction.

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 two sentences long, front-loaded with the primary purpose, and includes only essential additional details about subdirectories and empty-list handling. No filler 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 zero-parameter read-only tool with an output schema, the description fully covers the return semantics and a common edge case (empty list). No significant gaps remain.

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 schema description coverage is 100% (trivially). The description adds no parameter-specific semantics, but the baseline for zero-parameter tools is 4, and it does add a note about empty-result configuration that indirectly relates to setup.

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 returns the list of directories the server is allowed to access, using a specific verb and resource. It distinguishes from sibling listing tools like list_directory by focusing on access permissions, and adds that subdirectories are also accessible.

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 provides useful context about what the result means and what to do if empty (add directory paths in .mcp.json), but it does not explicitly discuss when to use this tool vs alternatives like list_directory or tree. The usage is implied rather than clearly differentiated.

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