Lists Windows drive roots to select a filesystem target. The VM session remains locked, so finish by calling vm_unlock.
List available Windows drive roots for filesystem browsing. VM remains locked by this session; call vm_unlock when finished.
| Name | Required | Description | Default |
|---|---|---|---|
| vm_name | Yes | Unique VM name configured in WIN98CTL.INI. |
Changes observed during successful MCP inspections.
v1.7.0Input schema / properties / vm_nameAdded value: +{
+ "description": "Unique VM name configured in WIN98CTL.INI.",
+ "pattern": "^[A-Za-z0-9][A-Za-z0-9._-]{0,63}$",
+ "type": "string"
+}Input schema / requiredAdded value: +[
+ "vm_name"
+]v1.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and idempotentHint=true, but the description adds valuable behavioral context beyond those: the VM remains locked by this session and requires vm_unlock when done. This is a meaningful side effect that annotations alone would not convey.
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, zero redundant wording. The primary action is front-loaded, and the critical lock-related instruction is placed second where it is still easy to notice.
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 simple list operation with a single fully documented parameter, the description is nearly complete. The main gap is that it does not explicitly describe the output format, which is slightly more important since there is no output schema, but the phrase 'drive roots' sufficiently implies the result for an agent.
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 coverage is 100%, and the vm_name parameter is already fully documented in the schema with a description and pattern. The tool description adds no additional parameter-level meaning, which is acceptable given the schema handles it.
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 combines a specific verb ('List') with a clear resource ('available Windows drive roots') and a stated purpose ('for filesystem browsing'). This clearly distinguishes it from sibling tools like fs_list, which list directory contents rather than drive roots.
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 a clear inherent context for when the tool would be used, but it does not explicitly name alternatives or state when not to use it. The lock note ('call vm_unlock when finished') provides useful sequencing guidance, but there is no direct comparison to sibling filesystem tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.