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

No annotations exist, so description must cover behavioral traits. It only states the operation, omitting critical details like side effects (none expected), security considerations, or output format. For a cryptographic tool, more transparency is 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?

Extremely terse at one sentence, but lacks information. Conciseness should not come at the cost of utility. A more informative single sentence could improve context.

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?

Despite having output schema, the description is too sparse to be complete given the complexity (cryptographic function) and presence of many siblings. It fails to contextualize the tool's role or security aspects.

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 covers both parameters (key, message) with descriptions (100% coverage). Description adds no additional meaning, so baseline 3 is appropriate.

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?

Description states the action (Generate) and algorithm (HMAC-SHA256), but is minimal. Among sibling tools like generate_hmac, hmac_md5, hmac_sha512, it lacks differentiation, making the purpose vague without context.

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. With many related tools (e.g., generate_hmac, hmac_md5, hmac_sha512), the description fails to specify criteria for selection.

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