Delete a previously saved QEMU snapshot to reclaim qcow2 disk space and report failure if QEMU rejects the tag.
Delete a snapshot previously saved with qemu_snapshot_save.
Frees the space it used inside the qcow2 disk. Reports failure if QEMU's delvm rejects it (e.g. an unknown tag) instead of claiming success.
| Name | Required | Description | Default |
|---|---|---|---|
| tag | Yes | ||
| name | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true and readOnlyHint=false, so the safety profile is covered; the description earns credit for adding what is destroyed (space inside the qcow2 disk is freed) and the error contract (a failing delvm surfaces as failure rather than silent success). The mention of QEMU's delvm rejecting an unknown tag is real behavioral context not present in the annotations. It does not discuss the interaction between idempotentHint=true and erroring on an unknown tag, which is a minor omission.
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 the action front-loaded and the effect and error behavior following. No filler, no restatement of the title.
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?
The tool is simple and an output schema exists, so return values need no explanation. However, with zero schema coverage, the unexplained 'name' parameter leaves an agent guessing about scope (which VM the snapshot belongs to), which is a meaningful gap for a destructive operation.
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 0%, so the description must carry parameter meaning, and it largely does not. "Unknown tag" hints that 'tag' identifies the snapshot, but the required 'name' parameter (presumably the VM name) is never explained, and there is no format guidance for either.
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?
Specific verb plus resource ("Delete a snapshot") with an explicit lineage tie to qemu_snapshot_save, so the agent knows this is the inverse of the save tool. It does not explicitly distinguish itself from qemu_snapshot_load or qemu_snapshot_list, so the sibling separation stops just short of a 5.
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 phrase "previously saved with qemu_snapshot_save" implies a precondition (the snapshot must already exist), and the failure note implies a guard, but there is no explicit when-not or direct comparison to qemu_snapshot_load for removing vs. reverting. Usage is implied rather than spelled out.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.