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

Annotations already declare destructiveHint=true, readOnlyHint=false, and idempotentHint=false, so the agent knows this is a mutating, non-idempotent operation. The description adds the context that it operates on a paired computer and that it handles tar or zip formats, but it does not disclose what happens on overwrite, whether the archive is deleted after extraction, or whether extraction is recursive. With annotations covering the safety profile, a 3 is appropriate.

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?

A single sentence that front-loads the trigger condition and the resource type. Zero wasted words. It earns its place by stating the exact use case and the supported formats.

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 has an output schema, so return values are already documented. The description plus annotations cover the safety profile (destructive, non-idempotent) and the trigger condition. The only missing context is what happens on conflicts (e.g., overwriting existing files) and whether the archive is removed after extraction, but these are minor for a straightforward extraction tool.

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 the schema already documents all three parameters (archive, device, destination). The description adds the format constraint ('tar or zip') and the default behavior for destination ('Defaults to the archive directory' is in the schema, not the description). The description does not add meaning beyond the schema, so the baseline 3 is correct.

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 states a specific verb ('extract'), a specific resource ('tar or zip archive'), and a clear target ('unpacked on a paired computer'). It distinguishes itself from the sibling create_archive, which performs the inverse operation, and from file-manipulation tools like copy_file or move_file. The phrase 'on a paired computer' also clarifies the remote-device context.

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 explicitly says 'Use this when the user wants an existing tar or zip archive unpacked on a paired computer,' which gives a clear trigger condition. It does not explicitly name alternatives or exclusions (e.g., when to use create_archive or when not to use it), but the trigger is specific enough that an agent can select it correctly. A small gap: it doesn't mention that the archive must already exist or that the destination must be writable.

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