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

Despite annotations marking the tool as not read-only, not idempotent, and not destructive, the description adds vital behavioral context: the key is returned only once and cannot be recovered (only SHA-256 stored), the minting does not authenticate the connection, the client sends the key, and configuration details are provided. This far exceeds what annotations convey and prevents catastrophic misuse. No contradiction with annotations.

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?

The description is dense but each sentence earns its place: purpose, one-time return warning, authentication caveat, retry guidance, and duplicate policy. It front-loads the core purpose before the critical warnings. It could be slightly trimmed (e.g., repeating 'no card' and 'no signup flow' is minor), but the length is justified by the high stakes of key loss.

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 nested objects, the description covers all essential behaviors: key issuance parameters, one-time retrieval, storage, authentication failure modes, retry policy, and duplicate handling. It is complete enough for an agent to call correctly and understand consequences. A minor gap is that it doesn't describe the exact success/error response format, but given no output schema, this is covered enough by the behavioral warnings.

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?

The only parameter, email, is fully documented in the schema (format, description, and the one-free-key-per-address note). Since schema description coverage is 100%, the description doesn't need to add more about the parameter itself. The description reinforces the email constraint but adds no new semantics beyond the schema, so a 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?

The description opens with a specific verb ('Mint') and a clear resource ('free Attestwire API key'), plus concrete limits (100 documents/month, no signup flow, no card). It clearly distinguishes itself from sibling tools that validate, verify, or diagnose invoices/VAT, and the scoping ('for the tools that need one') makes the intent unambiguous.

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 description explicitly states when to use the tool (for tools that need an API key) and provides strong guidance on what NOT to do: do not retry a keyed tool before the key is saved/configured. It also warns about duplicate issuance (second call returns 409). While it doesn't explicitly name alternative tools, the context is self-contained and clear enough for an agent to decide when to call this tool.

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