cp

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

Discloses destructive nature ('Destructive to destination: creates new copies on the filesystem') and safety features (dry-run, overwrite protection). Adds context beyond destructiveHint annotation.

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?

Five focused sentences, front-loaded with purpose and key features. Every sentence adds value without fluff.

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?

Complete for a copy tool: explains return type (JSON with source/destination), safety mechanisms, and when to use alternatives. No missing info given lack of output schema.

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 100%, baseline 3. Description adds value by explaining defaults ('Overwrite protection enabled by default') and usage of --allow_overwrite and --dry_run flags, but does not detail all params.

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?

Clearly states 'Copy files and directories' with specific verb and resource. Distinguishes from siblings by explicitly stating not for moving ('use mv') or setting permissions ('use install').

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?

Provides explicit guidance: 'Use to duplicate files or directories' and 'Not for moving files — use "mv"' and 'Not for setting permissions — use "install"'. Clearly tells when and when not to use.

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