chmod

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

Discloses destructive nature (modifies filesystem bit) beyond the destructiveHint annotation, and adds useful behaviors like --dry_run for preview and return format (JSON with old/new mode). No contradictions with annotations.

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?

Three sentences, each carrying distinct value: purpose+destructiveness, preview+return, usage guidance+alternatives. No redundancy or filler.

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?

Covers return format and references siblings, but does not address error cases or permission requirements. Acceptable given schema covers all parameters and annotations provide destructive hint.

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%, so baseline 3. Description does not add significant new information beyond what schema already provides (e.g., octal modes, dry_run preview). Fulfills minimal requirement.

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?

Description clearly states it changes file permissions using octal modes, specifies the resource (filesystem permission bits), and differentiates from ownership changes by referencing chown/chgrp.

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?

Explicitly says when to use (control read/write/execute access) and when not to (ownership changes), and points to alternative tools chown and chgrp. Also recommends --dry_run for preview.

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