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

The description is exceptionally strong on behavioral traits beyond the annotations. It specifies the implementation environment ('Pure code and WebCrypto'), the pricing structure ($0.002), input limits (up to 1MB), and technical verification status for certain algorithms (RFC 1321).

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?

Despite being technical and detailed, the structure is highly efficient. It flows logically from core function to supported methods, constraints, output format, and operational costs.

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 definition is extremely robust. It provides an exhaustive list of functionality, implementation details, performance constraints (limit), and financial costs, making it complete for any agent attempting to use it.

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?

Even with 100% schema coverage, the description adds critical semantic meaning. It clarifies that the 'input' parameter can be text or base64 depending on the 'encoding' setting and precisely defines the expected format of the 'algorithms' string (comma-separated list).

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 purpose is clearly defined as hashing text or base64 input. It specifies a wide variety of supported cryptographic functions (MD5, SHA, CRC, HMAC), which makes the resource usage precise.

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?

While it doesn't explicitly list alternatives, it provides strong usage guidance by detailing when specific parameters are needed (e.g., providing a key for HMAC, specifying an encoding, or listing desired algorithms).

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