sha256sum

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

Annotations already indicate read-only; description adds 'no side effects' and details return format (JSON per-file hash values). Could mention memory/performance for large files, but still strong.

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?

Concise: 4-5 sentences front-loaded with main action, then read-only note, return format, and use cases. No superfluous content.

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?

Given one parameter, clear annotations, and no output schema, the description fully covers purpose, usage, safety, and return format. No gaps.

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% with a clear description for the single parameter. The tool description does not add further parameter-level detail beyond confirming it hashes files or stdin.

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 uses a specific verb ('Compute') and resource ('files or stdin'), clearly states it is the standard cryptographic hash, and distinguishes from siblings by mentioning alternatives like md5sum and b2sum.

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 states when to use (cryptographic integrity, security-sensitive) and when not (high-speed non-security), naming alternative tools (md5sum, b2sum).

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