fast-filesystem-mcp

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. 'Synchronizes two directories' implies a potentially destructive operation that could modify or delete files, but the description doesn't warn about data loss risks, permission requirements, performance characteristics, or what happens when conflicts occur. For a tool with 7 parameters that can delete files, this is inadequate.

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 maximally concise at just three words. It's front-loaded with the core purpose and contains zero wasted words or redundant information. This is an example of efficient communication when the schema provides detailed parameter documentation.

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 complex synchronization tool with 7 parameters, no annotations, and no output schema, the description is insufficient. It doesn't explain what synchronization means operationally, what gets returned, error conditions, or performance expectations. The agent must rely entirely on the parameter schema without contextual guidance about the tool's behavior.

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 the schema already documents all 7 parameters thoroughly. The description adds no parameter information beyond what's in the schema - it doesn't explain the relationship between sync_mode options, when to use delete_extra, or how preserve_newer interacts with sync_mode. Baseline 3 is appropriate when the schema does the heavy lifting.

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 'Synchronizes two directories' clearly states the action (synchronizes) and resource (directories), but it's vague about what synchronization entails. It doesn't distinguish this tool from potential sibling operations like fast_copy_file or fast_move_file beyond the general concept of synchronization.

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 multiple file operation siblings available (fast_copy_file, fast_move_file, fast_batch_file_operations), there's no indication of when directory synchronization is preferred over other approaches or what specific problems it solves.

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