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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds the default sort order ('newest first'), which is genuine behavioral context, but says nothing about pagination mechanics, rate limits, or how many calls the agent must make despite exposing an offset token.

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 zero filler: purpose, filters, and API endpoint. Every sentence earns its place.

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 simple 0-required-param list tool with no output schema and full schema coverage, the description covers purpose, ordering, and filters adequately. It could have noted the pagination loop (repeat until next_offset is absent) since there is no output schema to clarify return shape, but the gap is minor.

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 every parameter (email, limit, offset, created_after) is already documented with Chargebee-specific mapping notes like '→ email[is]'. The description adds no parameter detail beyond what the schema provides, 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?

Specific verb+resource ('List customers') plus scope details (newest-first ordering, filterable by email or creation time) and the underlying API endpoint. It's clearly distinguishable from chargebee_get_customer / chargebee_create_customer by the list semantics, though it never names a sibling explicitly.

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 usage by stating the available filters ('Filter by email or creation time'), which tells the agent when this tool is appropriate, but there is no explicit when-to-use versus chargebee_get_customer or the other list_* tools, and no exclusions.

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