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

The readOnlyHint annotation already establishes this is a safe, non-mutating read, and the description does not contradict it. Beyond restating the endpoint, the description adds no behavioral context such as pagination semantics, default page size, ordering, or rate limits, so it clears the lowered bar but adds little.

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, front-loaded sentences with the core purpose first and no filler. The API endpoint line is marginally useful but borders on redundant given the tool name.

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 list tool with a fully documented schema and no output schema, the definition covers what is needed to invoke it. It could still note pagination behavior and result ordering, but nothing essential is missing.

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 limit, offset, status, and customer_id are already fully documented in the schema, including the enum values and the Chargebee filter mapping. The description only names two of the four filters and adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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 (list) and resource (invoices) and names the two filter dimensions, so it is clearly distinct from chargebee_get_invoice (single invoice) and the other list_* siblings. It stops short of explicitly contrasting itself with the sibling retrieval tools, which keeps it from a 5.

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?

"Filter by customer or status" implies the intended use cases but never states when to reach for this versus chargebee_get_invoice or chargebee_list_credit_notes, nor any exclusions or prerequisites. Usage must be inferred from the tool name and filter list.

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