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

With no annotations, the description carries the full burden: it usefully discloses the non-goal (no cracking/reversing) and the cost model (1 credit per call), which are real behavioral traits. However, it says nothing about result shape (single best guess vs. ranked candidates), confidence, or accuracy limits for ambiguous lengths/formats.

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 plus a short cost line, with the core purpose and the algorithm families front-loaded. Every clause carries information; nothing is padding.

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 single-parameter tool with no output schema and no annotations, the description covers purpose, scope boundary, and cost, which is close to what an agent needs. The one remaining gap is that it never characterizes the return value, which the absence of an output schema leaves entirely to the agent's imagination.

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?

One parameter at 0% schema coverage: the description implies the input is the raw hash string and that length/format are what get analyzed, which is useful orientation. It adds no syntax, encoding, or formatting guidance (e.g., how to pass crypt strings, whether prefixes like '$2y$' are required) and doesn't explain the 8–300 char bounds.

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 (guess/identify) and resource (hash type) plus the concrete algorithm families covered (MD5, SHA, bcrypt, argon2, crypt). The clause 'Does not crack or reverse hashes' cleanly separates it from any cracking-adjacent tool, so an agent can pick it without opening the schema.

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?

The negative scope ('does not crack or reverse hashes') gives the agent an explicit when-not condition, which is more than most definitions offer. It stops short of naming a sibling to use instead (e.g., password_check or jwt_inspect for those adjacent tasks), so it is clear context rather than a full routing rule.

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