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

Annotations already declare it is a non-read-only, open-world, non-idempotent, non-destructive mutation. The description goes well beyond by enumerating the two distinct outcomes, explaining that setup_required means no case exists yet, instructing the agent not to claim creation, and warning against contacting anyone prematurely. This is rich, non-obvious behavioral context.

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?

Front-loads the purpose and precondition, then uses a clearly labeled 'Two outcomes' list that maps each response to a required agent action. It is somewhat long, but nearly every sentence carries actionable instruction rather than 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 an output schema, the safety profile is covered by annotations and the response handling is covered by the outcome enumeration, so the agent knows how to behave. The remaining gap is the total absence of parameter guidance, which is the one thing an agent must supply to make the call.

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% across 6 parameters, only one required, and the description never mentions any parameter (amount_cents, counterparty, billing_period, automatic_change, observed_signals, expense_description) or their expected formats. With low coverage the description was expected to compensate but does not.

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?

Opens with a specific verb and resource: 'Open a Dueback negotiation case.' This clearly distinguishes it from siblings like detect_negotiable_bill (detection), get_case_status (status read), and list_verified_savings (listing). An agent can identify the action without opening the schema.

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?

Explicitly states the precondition: 'Only call after the human approved the pitch from detect_negotiable_bill.' This names the required prior sibling call and the gating condition, leaving nothing to inference about when to invoke it.

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