filesystem-mcp

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

With no annotations provided, the description carries full burden but only states the action without behavioral details. It doesn't disclose whether this requires elevated permissions, if changes are destructive or reversible, potential side effects on nested items, or error handling for invalid paths/modes. 'Change permissions' implies mutation but lacks critical safety and operational 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 a single, efficient sentence with zero wasted words. It front-loads the core action ('Change permissions mode') and includes essential technical context ('POSIX-style') without unnecessary elaboration.

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 mutation tool with no annotations and no output schema, the description is incomplete. It lacks information about permissions required, whether changes apply recursively, what happens on partial failures, or the return format. Given the complexity of file system operations and absence of structured safety hints, more behavioral disclosure is needed.

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. The description adds minimal value beyond implying 'multiple' paths (hinting at array usage) and POSIX context, but doesn't elaborate on parameter interactions or usage nuances beyond what the schema already provides.

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 verb ('Change permissions mode') and resource ('multiple specified files/directories'), with the parenthetical '(POSIX-style)' adding technical specificity. It distinguishes from siblings like chown_items (ownership changes) and delete_items (removal), but doesn't explicitly contrast with them.

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?

No guidance is provided on when to use this tool versus alternatives like chown_items for ownership changes or stat_items for checking permissions. The description implies it's for permission modification but offers no context about prerequisites, constraints, or appropriate scenarios.

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