hmac_sign

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

Despite no annotations, the description fully discloses inputs (hex-encoded key, data, algorithm), output (hex-encoded HMAC), and provides an example. It's a pure function without side effects, so little else needed.

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?

Description is brief, structured with Args/Returns/Example, front-loads purpose. Every sentence adds value, no redundancy.

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?

For a simple deterministic HMAC function, the description covers all aspects: inputs, output format, default behavior, and example. No gaps remain given tool simplicity and presence of output schema implicitly (hex string).

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%, but the description adds complete semantic meaning: key format (hex-encoded), data role (string to sign), algorithm values (sha256 or sha512) with default. This fully compensates for missing schema descriptions.

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?

The description explicitly states 'Generate HMAC' with a specific verb and resource. It clearly distinguishes from siblings like hmac_verify (verification) and hash_sha256 (hashing without key).

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?

No guidance on when to use this tool versus alternatives like rsa_sign or hmac_verify. The agent receives no hints about prerequisites, symmetric vs asymmetric, or comparison with siblings.

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