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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower and the description clears it by disclosing the billing model ($0.001 USDC per successful call), the payment rail, and a direct HTTPS alternative for the same computation. It stops short of describing failure modes such as what happens on a failed payment or an over-length input.

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?

Four short sentences, front-loaded with the algorithm definition, then a test vector, then operational facts. Every sentence carries non-redundant information and nothing is wasted.

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?

With no output schema, the embedded example adequately conveys the return format, and pricing is covered. The gap is input selection: a two-parameter, zero-required tool with no schema descriptions leaves the agent unsure whether to pass hex, text, or both, which the description does not resolve.

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% and neither parameter is documented in the schema, so the description carries the burden. It partially compensates by defining the byte interpretation (big-endian 16-bit words, zero-padded final odd byte) and demonstrating a text input, but it never maps those semantics to the `hex` and `text` fields, never says whether they are mutually exclusive, and never states precedence when both are supplied despite zero required parameters.

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?

Names a specific algorithm variant (Fletcher-32, modulus 65535) rather than a vague 'checksum' verb, and the variant naming alone separates it from siblings like fletcher16, crc16 and inet_checksum. The worked example "abcde" -> 4ff029c7 confirms unambiguously what the tool computes.

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 only implied by the purpose statement; there is no explicit statement of when to pick Fletcher-32 over fletcher16/crc16 or what inputs are appropriate. It does supply operational context an agent needs before calling (cost per successful call, x402/Solana payment, and an equivalent HTTPS endpoint), which is real routing value but not when-to-use guidance.

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