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

Annotations cover the safe, read-only, idempotent nature. Beyond that, the description discloses the paid x402/USDC cost model, supported algorithm families, input/output encodings, HMAC key support, and the exact return payload contents, which is rich behavioral context.

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?

The description is a single dense paragraph, front-loads the core operation and algorithm support, then adds encoding details, return shape, and pricing. Every sentence carries information useful for selection or invocation.

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 six-parameter cryptographic tool with no output schema, the description explains the main return values: digest, input byte length, and algorithm identifier. It does not specify exact output field names or error payloads, but the agent has enough to invoke it correctly.

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 description coverage is 100%, and all six parameters already have enum or constraint descriptions in the schema. The description restates the algorithm and encoding options but adds little syntactic or default detail beyond what the schema provides.

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 states a specific verb+resource: compute a cryptographic digest of supplied data. It enumerates supported algorithms, HMAC, input encodings, output encodings, and return contents, so the agent can identify exactly what the tool does without opening the schema.

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 implies usage through a detailed capability list, but it does not explicitly state when to use this tool versus alternatives or when not to use it. No sibling tool competes for hashing, so the gap is modest but present.

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