Update Purchase Invoice

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

Annotations include idempotentHint=true but no other behavioral details. The description adds critical context: server-managed fields are rejected and confirmed invoices need invalidation first. 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?

Two concise sentences front-loading the main purpose and constraints. No unnecessary words; every piece contributes to understanding usage.

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?

Covers key operational constraints (draft state, field restrictions, prerequisite for confirmed invoices). No output schema exists, so return info is not expected. Could mention success response, but completeness is high for the tool's complexity.

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 description coverage is 100% (both parameters documented). The description adds value beyond schema by warning server-managed fields are rejected, which informs which fields are permissible. This justifies a 4 above the 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?

Clearly states the tool updates draft purchase-invoice fields, distinguishing it from other invoice-related tools like confirm or invalidate. The verb 'update' and resource 'purchase-invoice' are specific, and 'draft' adds important scope.

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?

Provides explicit when-to-use guidance: only for draft invoices. States that server-managed fields will be rejected and that confirmed invoices require prior invalidation, offering clear directions and alternatives.

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