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

With no annotations, the description carries the full burden, and it does add genuinely useful behavioral context: the tool is paid, with three accepted payment rails (x402 USDC, Cashu ecash, Lightning L402). However, it discloses nothing about the return shape (whether one hash or a set is returned) or error behavior for invalid algorithms.

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?

Two sentences, front-loaded with the hashing behavior before the payment detail, with no filler. The payment sentence is dense with three price points but each is relevant to calling the tool successfully.

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 utility with no output schema and no annotations, the description covers algorithms, default behavior, HMAC, and cost. The main remaining gap is the shape of the returned hashes, which the absent output schema would otherwise need to supply.

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 0%, so the description must compensate. It explains the alg values (md5, sha1, sha256, sha512, default all) and that key enables HMAC, which covers two of three parameters meaningfully, but it omits the exact accepted string format for alg and does not describe the text parameter's treatment.

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?

States a specific verb (hashes) and resource (text), and enumerates the four algorithms plus optional HMAC, which concretely distinguishes it from vaguer siblings like encode or crypto. An agent can tell what it produces 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?

There is no guidance on when to use this versus siblings like encode or crypto, no exclusions, and no prerequisites beyond the payment note. The default-all-algorithms and HMAC-with-key behavior implies some usage, but no explicit when/when-not is offered.

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