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 disclose genuinely important context: the 1000 atomic USDC cost and that payment authorization is required before execution. It still omits the output form (64-char hex digest), determinism, and whether results are cached or side-effect free, so it is only partially complete for an unannotated tool.

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 short sentences, front-loaded with the core purpose; the cost and payment caveat earn their place as operational constraints. Slightly terse on the return value, but nothing is padded or redundant.

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 trivial single-input hashing tool with no output schema or annotations, the description covers purpose, input type, exclusions, and the payment prerequisite. The main omission is the return format, which an agent would need since no output schema exists to describe 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?

Schema coverage is 0% on the single 'text' parameter, so the description must compensate. It adds a real constraint by specifying the input is UTF-8 text with no file fetching, but it never states the min/max length limits (1-3000) that the schema enforces, leaving the agent unable to anticipate rejection.

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 precise verb+resource: 'Return the SHA-256 fingerprint of supplied UTF-8 text.' It pins down the algorithm (SHA-256) and the input encoding (UTF-8), and the leading sentence clearly separates it from the codec/format siblings like base64_text_codec and json_normalize.

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 'No file fetching, identity check, or signature verification' clause scopes what the tool is not for, which is useful negative guidance. However, no sibling alternative is named and there is no explicit when-to-use statement, so the routing guidance is only implied.

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