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

With no annotations, the description carries the full burden. It correctly indicates the tool is a pure function (no side effects) and is free to use. The phrase 'hex digest' clarifies output format. It does not contradict annotations (none provided).

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 well-structured sentence with no wasted words. The critical 'FREE (no wallet needed)' qualifier is front-loaded. Every phrase earns its place.

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?

For a simple hash function with two parameters and no output schema, the description covers key aspects: supported algorithms, input, free usage. It doesn't mention output length or edge cases, but these are standard expectations for a hash 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 coverage is 0%, so the description must explain parameters. It does: 'SHA-1/256/384/512' maps to the 'algo' enum, and 'of a string' explains 'data'. This adds meaning beyond the schema's bare type definitions.

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 ('hex digest' meaning compute hash) and resource ('a string'), listing all supported algorithms (SHA-1/256/384/512). It clearly distinguishes from sibling tools like base64 (encoding) or random_numbers (random generation).

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 mentions it is free and no wallet needed, implying low-barrier usage. However, it gives no guidance on when to use this tool over alternatives or which algorithm to choose, leaving the agent to infer from context.

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