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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds context about what the tool returns (letters, escalation stages, next steps) but doesn't disclose details like whether the 'on' date affects the escalation state or whether the response includes computed fields. With annotations covering the key behavioral traits, a 3 is appropriate.

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, well-structured sentence that front-loads the core purpose ('One chased invoice in full') and then lists the key contents in a natural flow. No wasted words, and it earns its length by enumerating the distinct data categories.

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 read-only, idempotent lookup tool with 100% schema coverage and no output schema, the description covers the main things an agent needs: what the tool does and what data it returns. It doesn't explain the escalation schedule format or how 'on' interacts with the data, but those are minor gaps given the annotations and schema already carry the safety and parameter details.

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 both parameters ('on' and 'invoice') are already documented in the schema. The description doesn't add extra meaning beyond what the schema provides, but it does reinforce that the tool is about a single invoice's full state. Baseline 3 is correct.

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 uses a specific verb ('chased invoice in full') and enumerates the exact resource contents: billed, paid, owed, letters sent, escalation schedule, and next steps. It clearly distinguishes itself from siblings like aging_summary or overdue_list by focusing on a single invoice's full state.

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 implies this is the tool to use when you need the complete state of one chased invoice, including escalation and next actions. It doesn't explicitly name alternatives or exclusions, but the scope is clear enough that an agent can infer when to use it versus a list-level tool like overdue_list or aging_summary.

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