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

Beyond the annotations, the description adds important behavioral context: the operation is deterministic, returns a hex digest, and has a settlement cost with 'no charge on failure.' It does not mention authorization, rate limits, or side effects, but the annotations already indicate it is not read-only and not destructive.

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 three sentences with no filler: algorithms are front-loaded, the output format is stated, usage guidance is explicit, and the cost model is included. Every sentence 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?

The description covers purpose, supported algorithms, output format, invocation guidance, and billing/failure behavior. Since an output schema exists, return-value details are not needed. The main gap is that encoding values and KDF-specific parameters (e.g., salt or iteration handling) are not clarified, though the schema covers the key requirement.

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%, but the algorithm parameter is only described as 'Hash algorithm,' which is unhelpful. The tool description compensates by explicitly listing the accepted algorithms (SHA-256, SHA-384, SHA-512, HMAC-SHA256, PBKDF2, scrypt) and the hex output format. It still leaves the meaning of the 'encoding' parameter vague.

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 names a specific verb and resource: 'Deterministic hashing of arbitrary input' and enumerates exactly which algorithms are supported. It also states the return format ('Returns hex digest'), which makes it easy to distinguish from compute_encode, compute_infer, and other sibling tools.

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?

It gives explicit when-to-use guidance ('MUST be invoked when an agent needs a cryptographic hash or key derivation') and explicit when-not-to-use ('Do NOT use for encryption or signing'). However, it does not name alternative sibling tools that should be used for encryption or encoding.

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