vm_start

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

With no annotations provided, the description carries the full burden of disclosing behavioral traits. It does convey the headless-by-default behavior, but it does not specify what happens if the VM is already running, whether the operation can fail due to VM state, or what output is returned. The 'or resume' hint is vague about state handling.

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, compact sentence with the primary action front-loaded. It wastes no words, though it could have been slightly more informative about state behavior or sibling relationship without becoming verbose.

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 start tool, the description gives the core purpose, but it omits important contextual details: how to handle an already-running VM, the distinction from vm_resume, and any prerequisites beyond the schema-documented 'vm' parameter. Since there is no output schema and no annotations, these gaps leave the agent with material uncertainty.

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 both parameters (vm and gui) are already documented in the input schema. The description adds no new parameter-level detail beyond reinforcing that GUI is off by default, which is already encoded in the schema's default value. A baseline 3 is appropriate.

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 uses a specific verb and resource: 'Power on (or resume) a VM'. It clearly indicates the tool's action, but the phrase '(or resume)' overlaps semantically with the sibling tool vm_resume, so differentiation from that sibling is not fully addressed.

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 implies that this tool starts a VM headlessly, which is a clear usage context, but it provides no explicit guidance on when to use vm_start versus sibling tools like vm_resume, vm_stop, or vm_suspend. No exclusions or alternative conditions are given, leaving selection partly to inference.

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