update_vm

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It opens with 'DESTRUCTIVE:' to warn about mutation, explains partial-update behavior ('only non-empty/non-zero fields are applied'), and reveals the preview and confirmation mechanism. This gives the agent a clear expectation of side effects and execution flow.

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 concise and well-structured, starting with a critical DESTRUCTIVE warning, followed by usage notes, then a clear argument list. Every sentence provides necessary information without redundant filler. The 'Args:' section is easy to scan and maps directly to the schema.

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 complex 8-parameter mutation tool with no annotations, the description is remarkably complete. It covers preconditions, partial-update semantics, parameter meanings, and the confirm/preview workflow. The presence of an output schema means return values need not be described, so all necessary context is present.

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 input schema has 0% description coverage, so the description fully compensates by explaining every parameter: vm_id identifies the VM, name and description use empty strings to keep current values, cores and memory_mb use 0 to keep current, auto_start accepts 'on'/'off'/'last', auto_start_delay uses -1 to keep current, and confirm must be true for execution. This adds essential meaning beyond the bare schema.

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 purpose: 'Update virtual machine settings.' It uses a specific verb and resource, and the tool name 'update_vm' is differentiated from siblings like create_vm, delete_vm, and start_vm by its focus on modifying settings.

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 provides explicit usage guidance: the VM should be stopped before changing CPU or memory, and only non-empty/non-zero fields are applied. It also explains that confirm must be true to execute and otherwise returns a preview. However, it does not explicitly mention alternatives or when-not-to-use scenarios, so it falls short of a 5.

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