vm_resize_disk

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

Annotations already declare destructiveHint=true and idempotentHint=false, but the description adds the crucial operational facts: growth is irreversible with 'No undo token', and dry_run provides a preview path. This tells the agent exactly what is at risk and how to mitigate it, well beyond the structured hints.

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?

Front-loads the write tag and the grow-only/irreversibility warning before the Args block, so the highest-risk facts land first. The Args list is terse and each entry adds real information rather than restating the parameter name.

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 destructive, non-idempotent mutation with no output schema, the description covers the essential risk surface (irreversibility, dry_run) and every parameter. It omits prerequisites such as required VM power state or permission scope, which would round it out, but nothing critical is missing.

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 carries the full burden and does: it documents all six parameters, gives concrete disk-key examples ('scsi0', 'virtio0', 'sata0'), specifies the size format ('+<N>G' increment or larger absolute size), and explains that node may be omitted to auto-locate. This fully compensates for the empty 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?

States a specific verb and resource ('Grow a VM disk') and immediately narrows scope with 'GROW-ONLY — shrink requests are refused.' An agent can distinguish this from disk-adjacent siblings like vm_move_disk or vm_reconfigure without opening any schema.

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?

Gives clear operational context: grow-only semantics, refusal of shrink requests, and 'Pass dry_run=True to preview' for safe exploration. It stops short of naming alternatives (e.g., vm_reconfigure) or stating prerequisites like VM power state, so it is clear context without explicit alternative routing.

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