qemu_disk_create

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

Annotations only say it is non-read-only, non-idempotent and non-destructive; the description adds the crucial failure mode (fails if path already exists instead of overwriting, consistent with idempotentHint=false) and warns that qemu_boot's format auto-detection only distinguishes qcow2 from raw, so other formats silently degrade. That is real behavioral context beyond the annotation block.

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-loaded with purpose and the qemu_boot dependency, then parameters, then the failure mode. Slightly redundant in the middle - 'qemu_boot never creates a disk image itself' and 'This closes that gap: create one here, then boot straight into it' say overlapping things - but nothing is wasted overall.

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?

An output schema exists, so return values need not be described; with purpose, sibling relationship, parameter grammar, format constraints and the existing-path failure all covered, an agent has everything needed to invoke it correctly on the first attempt.

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 0%, so the description carries the full burden and does: it spells out qemu-img size grammar with unit suffixes and examples ('10G', '512M'), restricts format to exactly two valid values with a default, and implies path must not exist. All three parameters gain meaning absent from 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?

States a specific verb and resource ('Create a fresh disk image via qemu-img create') and immediately ties it to the sibling that needs it (qemu_boot's `disk` param), which lets an agent place it among the qemu_* tools without opening the 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?

Explains exactly when to use it: qemu_boot never creates images, so create here first, then boot. It also routes the format choice to siblings - 'qcow2' is required for qemu_snapshot_save/qemu_snapshot_load, 'raw' otherwise - which is explicit alternative-selection guidance.

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