list_roots

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

Annotations already cover readOnlyHint=true and openWorldHint=false, so the safety profile is known. The description adds genuinely new behavioral context beyond the annotations: the tool defines an access boundary, and paths outside it are refused by the server — useful for predicting failure modes of sibling file tools.

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?

Two short sentences with no filler. The resource identification comes first and the constraining rule second, which is the correct front-loading for an access-boundary tool.

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?

An output schema exists, so return values need not be described, and there are no parameters to document. For a simple read-only enumeration the description covers what the list represents, though it could note whether the result set is static or configuration-dependent.

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 takes zero parameters, so the baseline is 4. There is nothing parameter-wise for the description to compensate for, and schema description coverage is 100%.

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 names the resource precisely — the server's permitted root folders — and the second sentence adds the boundary rule. It is clear what an agent gets back, though it lacks an explicit verb like 'list' and never names a sibling to contrast against.

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?

'Every other path is refused' implies this should be consulted before passing paths to read_file/write_file, but that inference is left to the agent. There is no explicit when-to-call or when-not-to-call statement, and no sibling is named.

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