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

Annotations already cover the safety profile (readOnly, idempotent, closed-world), and the description layers on real behavioral context beyond them: a 200-calls-per-day limit on password hashes, salted slow-by-design output returned as a self-describing string, output format differences (hex vs. integer for crc32), and a no-auth requirement.

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 core action and algorithm list, dense with useful detail, and no filler sentences. It runs long as a few compound sentences but every clause conveys selection or behavioral information.

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?

Without an output schema, the description correctly explains return formats (hex digest, integer for crc32, self-describing string for password hashes) and covers rate limiting and auth needs. The only meaningful omission is the input-size bound on the data parameter.

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?

With 0% schema description coverage, the description must carry the burden. It does explain the algorithm parameter by grouping the enum members semantically (integrity vs. legacy vs. password), which adds meaning beyond the raw enum. However the data parameter — its string type and 250,000-character cap — is never addressed, leaving a required input undocumented.

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?

Opens with a concrete verb+resource (hash text) and enumerates the algorithm family, so the agent immediately understands it's a one-shot hashing utility. It clearly contrasts itself with neighboring utilities like encode_data or generate_random by naming cryptographic vs. password-hash modes.

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 explicit selection guidance: sha256/sha3_256/blake2b/blake3 for integrity checks, md5/sha1 only for legacy systems expecting them, and argon2id/bcrypt/scrypt for test-data password hashing. It does not route the agent to the sibling verify_hash tool for the verification half of the workflow, which would be the natural companion.

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