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

With no annotations the description carries the full burden. It does disclose useful behavior beyond the schema: output format (hex plus Base64) and the cost/payment model ($0.001 USDC on Base via x402), which is real operational context. It omits auth/wallet requirements for payment, rate limits, and what happens on oversized input (250k limit), leaving gaps.

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?

Two sentences, front-loaded with what it does, then supporting use cases and cost. Dense with minimal waste. The keyword-stuffed use-case list is slightly padded but still earns its place for retrieval.

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?

There is no output schema, so the description correctly explains the return format (hex plus Base64). It covers cost and supported algorithms. But for a payable tool with no annotations it leaves out default-algorithm behavior and payment/auth mechanics, which an agent needs before invoking.

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 50%, so the description compensates by naming the four supported algorithms (SHA256, SHA-512, SHA-1, MD5), which map to the 'algo' enum values, and by clarifying the input is UTF-8 text. It does not state a default algorithm when 'algo' is omitted, which is the main remaining ambiguity.

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: compute SHA256/SHA-512/SHA-1/MD5 checksums for UTF-8 text, returning hex plus Base64 digests. That is much clearer than a name like 'hash' alone. It does not, however, distinguish itself from closely related siblings such as hmac or multi-digest-checksum, so it falls short of a 5.

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?

Provides concrete use contexts ('checksum verification, integrity checks, content fingerprints, cache keys, deduplication and agent pipelines'), which tells an agent when this tool is appropriate. It never states when NOT to use it or names an alternative (e.g. hmac for keyed hashing), so no exclusions are given.

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