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

Annotations already declare non-readonly, non-destructive and open-world. The description adds real value beyond them: it requires explicit user confirmation, clarifies it signs an authorization, creates exactly one pending invoice, and enumerates non-effects (no pay/settle/activate/identity proof).

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, front-loaded with the confirmation gate, then the action, then the negative scope. No waste; every clause carries 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?

For a two-parameter mutation with no output schema, the description covers the confirmation requirement, the produced artifact (one pending invoice), and what it deliberately does not do. Only the origin/meaning of operation_id remains slightly implicit.

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 only 50%: confirm_invoice_creation is documented in-schema and the description reinforces its 'explicit confirmation' meaning. operation_id is undocumented in both places, though 'the prepared authorization' implies it references a prior prepare call. Partial compensation, baseline 3.

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 (sign + create) and resource (a pending NIP-05 name@frontiercrown.com invoice), naming the exact artifact. The contrast with prepare_grynvault_nip05_invoice (it consumes 'the prepared authorization') and with the supporter-invoice sibling is clear from the resource name.

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 a clear precondition ('after separate explicit user confirmation') and bounds the action with negatives ('does not pay, settle, activate, or prove identity'). It implies but never explicitly names prepare_grynvault_nip05_invoice as the required preceding step, so it stops just short of full routing guidance.

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