create_invoice

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

No annotations are provided, so the description carries full burden. It discloses important behaviors: auto-generation of invoice_id from book's invoice counter when omitted, currency fallback chain (customer's currency → book's default), and job grouping constraints (must belong to same customer, must be a customer-job with owner_type='customer'). For a mutation tool with no annotations, this is strong behavioral disclosure.

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 well-structured with a one-line summary followed by a clean Args list. Every sentence adds value - examples, defaults, interactions, and constraints. No filler or redundant content. Param-doc-per-line formatting makes scanning easy.

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 7-parameter invoice creation tool, the description covers all parameters with examples and fallback behaviors. It documents the job_id prerequisite (create_job first), which is critical domain knowledge. An output schema exists to handle return value documentation. The description is comprehensive for a complex creation tool.

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 0%, so the description fully compensates by explaining every parameter with concrete examples. Each parameter gets its own Args entry with type hints and example values: customer_id ('000001'), invoice_id ('INV-2026-001'), term ('Net 30'), date format (YYYY-MM-DD). This adds substantial meaning beyond the raw schema.

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 clearly states the verb+resource: 'Create a customer invoice.' It distinguishes from siblings like create_bill, create_credit_note, create_voucher, and create_job by explicitly naming the resource type. The 'Create' verb plus 'customer invoice' resource makes the purpose 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 provides clear context on when to use the tool, particularly around the job_id parameter, instructing to 'Use create_job first to define the job, then attach invoices to it via this parameter.' It also explains the currency fallback behavior. However, it doesn't explicitly state when NOT to use this tool vs. alternatives like create_bill, though the intended domain is clear.

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