Cross-Platform Filesystem MCP Server

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

No annotations are provided, so the description carries full burden for behavioral disclosure. While 'List contents' implies a read-only operation, it doesn't specify permissions needed, error handling (e.g., for non-existent paths), output format, or whether it's recursive. For a tool with no annotation coverage, this leaves significant behavioral gaps.

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 a single, efficient sentence with zero wasted words. It's front-loaded with the core purpose and appropriately sized for a simple listing tool, making it easy to parse quickly.

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?

Given no annotations, no output schema, and multiple sibling tools with overlapping functionality, the description is incomplete. It doesn't explain what 'contents' includes (files, directories, symlinks), how results are formatted, or how it differs from similar tools, leaving the agent with insufficient context for optimal use.

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%, with both parameters ('path' and 'showHidden') fully documented in the schema. The description adds no additional parameter semantics beyond what's already in the structured fields, so it meets the baseline score when schema coverage is high.

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 'List contents of a directory' clearly states the verb ('List') and resource ('contents of a directory'), making the purpose immediately understandable. However, it doesn't differentiate from sibling tools like 'get_current_directory' or 'search_files' which also involve directory/file operations, so it doesn't reach the highest score.

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 no guidance on when to use this tool versus alternatives. With siblings like 'get_current_directory' (which might list current directory) and 'search_files' (which might filter results), there's no indication of when 'list_directory' is preferred or what its specific scope is beyond the basic listing function.

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