fs_drives

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

The description adds valuable context beyond the annotations: 'VM remains locked by this session; call vm_unlock when finished.' This discloses a key behavioral trait (the lock state) that annotations (readOnlyHint, destructiveHint) do not cover. No contradiction with annotations.

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 extremely concise: two sentences, front-loaded with the primary purpose, followed by a critical locking note. Every word earns its place, with no 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 parameterless, output-schema-less tool with strong annotations, the description is complete. It states what it does, why (filesystem browsing), and the VM lock context. No additional information 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?

The tool has zero parameters, so the baseline is 4. There is no parameter semantics needed, and the description doesn't attempt to describe any.

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's function: 'List available Windows drive roots for filesystem browsing.' The verb 'List' and resource 'Windows drive roots' are specific, and the purpose 'filesystem browsing' distinguishes it from sibling tools like fs_list (which lists directory contents).

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 gives clear context for when to use the tool ('for filesystem browsing') but does not explicitly compare it to alternatives like fs_list or state when not to use it. The lock context implies a prerequisite (VM is locked) but that's more behavioral than usage guidance.

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