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

Annotations only supply readOnlyHint and openWorldHint; the description adds material context beyond them, notably the $0.002 USDC per-call cost via x402 and the op=all batching behavior. It stops short of describing error handling, input size limits, or output format, so it is not a 5.

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?

Front-loaded with the capability list, then the batching behavior, then the price — a sensible order with no filler. The first sentence is dense but every clause (each algorithm and encoding) does informational work.

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 should indicate the return shape (raw hex string vs. a JSON object of multiple digests), which it does not. What it does cover — supported ops, batching, and pricing — is adequate for invocation but leaves an agent guessing at the response.

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 only 33% (only `key` is annotated as 'For hmac-sha256'). The description partially compensates by listing the algorithm/encoding domain that the undocumented `op` parameter selects from, but it never gives the literal op values or explains `text` beyond the obvious.

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 verb+resource ('Hash and encode text') and enumerates the exact algorithms and encodings covered (SHA-256/1/512, MD5, HMAC-SHA256, Base64/Base64url, hex, URL, UUID). This clearly separates it from neighbors like abi_encode, jwt_decode, sign_verify, and password_check.

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 the enumeration of supported operations and the note that op=all returns every hash and encoding at once, which is a genuine selection hint. However, there is no explicit when-to-use/when-not guidance and no routing to or away from any sibling tool.

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