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

Annotations already cover read-only, non-destructive and non-idempotent, and the description reinforces that nothing is changed. It adds context the annotations do not carry: per-call pricing ($0.002 via x402 USDC or card key), 25 free calls, failed calls free, and that repeats are billed. Input semantics (UTF-8 vs 0x/hex bytes) are also noted.

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 capability list and input semantics are front-loaded, and the use cases and pricing trail behind. It is dense but nearly every sentence carries information; the pricing boilerplate is the only part that could be trimmed.

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 description effectively enumerates the returned values (MD5, SHA-1, SHA-256, SHA-384, SHA-512, Keccak-256, CRC-32, base64 SHA-256, SRI strings), which is what an agent needs to know about the response. Limits like the 100,000-character cap live in the schema, and no pagination or error behavior is described, but little is missing for a simple stateless hash call.

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 both parameters and the hex flag are fully documented in the schema itself. The description restates the hex behavior and the 'text=hello world' example, adding only marginal value beyond structured data.

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 and resource ('Every common hash of one input in a single call') and enumerates exactly which digests come back, including SRI strings and Keccak-256 for Ethereum. It also implicitly distinguishes itself from the sibling 'hash' tool by framing itself as the multi-algorithm option that is 'cheaper than hashing one algorithm at a time'.

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?

Gives concrete usage contexts (checksums, cache keys, file integrity, comparing digests across systems) and an inline example. It hints at the alternative ('hashing one algorithm at a time') but never names the sibling 'hash' tool or states when a single-algorithm call would be preferable.

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