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

With no annotations, the description carries the full behavioral burden. It usefully discloses the output formats and the 0.001 USDC per-call cost, but does not explain that the first call may return a 402 payment challenge or that hashing is deterministic/stateless beyond the schema's paymentProof note.

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?

Three compact sentences with the core return behavior front-loaded, followed by the default algorithm and payment cost. There is no filler, and each sentence contributes context an agent needs.

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 hashing utility with no output schema, the description covers what is returned and the default algorithm. The payment flow is complex but is fully delegated to the schema's paymentProof field, so the description is nearly complete, with only minor room to mention the 402 handshake.

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 100%, so the input schema already documents text, algo, and paymentProof in detail. The description adds only the default algorithm and pricing context, which is useful but does not meaningfully extend parameter semantics beyond the schema baseline.

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 and resource: it returns the hex and base64 digest of input text. It also names the default algorithm and the payment model, so an agent can immediately distinguish this hashing tool from siblings like base64 or text_stats.

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?

Usage is implied by 'digest of the input text' and the default sha256, but the description does not explicitly say when to use this tool versus alternatives such as base64 or other utility tools. It also omits the practical first-call/payment flow, leaving that to the schema.

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