Update Draft Invoice

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

No annotations are provided, so the description carries the full burden. It discloses the key behavioral constraint (draft-only, non-finalizing), which is useful. However, it says nothing about partial vs. full update semantics, permissions, or what happens to omitted fields — significant gaps for an unannotated mutation tool.

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?

Three short sentences, front-loaded with the core action. There is mild redundancy between 'Cannot be used to finalize' and 'not yet finalized,' but no wasted filler.

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 mutation tool with no annotations and no output schema, the draft-only constraint is correctly surfaced, but the update mechanics (partial vs. full, required-field behavior beyond 'id', response format) are unaddressed. Adequate but with clear gaps.

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%, so every parameter is already documented in the schema. The description adds no parameter-level meaning (e.g., whether fields are optional partial updates), 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?

States a specific verb and resource ('Update an existing draft invoice') and narrows scope to draft-only invoices, which implicitly distinguishes it from create_invoice and get_invoice. It does not name a sibling explicitly, but the draft constraint gives an agent enough to tell it apart.

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 a clear when-not condition: 'Cannot be used to finalize an invoice. Only draft invoices (not yet finalized) can be updated.' This is genuine selection guidance. It stops short of naming alternatives (e.g., a finalize/send tool), so it is not a 5.

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