fiken_update_invoice_draft

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

The description adds minimal value beyond the annotation (readOnlyHint: false), only confirming that the tool mutates state. It discloses no behavioral traits such as idempotency, required permissions, or effects of partial updates. The schema's many optional fields are not addressed.

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 a single sentence with no wasted words. It is direct and efficiently communicates the core function.

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?

Given the 19-parameter schema, lack of output schema, and minimal annotations, the one-sentence description severely under-communicates. It does not explain return values, side effects, or how to structure update requests, leaving the agent with insufficient context to use the tool effectively.

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?

With only 21% schema description coverage, the description should compensate but does not. It offers no parameter descriptions, default values, or usage context. The required parameters (draftId, type, daysUntilDueDate, customerId) are not even mentioned, leaving the agent without critical guidance.

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 'Updates an existing invoice draft' clearly specifies the action (update) and the resource (existing invoice draft). Among sibling tools like fiken_create_invoice_draft, fiken_get_invoice_draft, and fiken_delete_invoice_draft, it is unambiguous and well-differentiated.

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 provides no guidance on when to use this tool versus alternatives (e.g., when to update vs create or delete). It lacks prerequisites, such as the draft being in a viable state, and does not mention any exclusion criteria.

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