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 the account-scoped behavior and the business-filtering hint, but it does not disclose pagination behavior beyond what the schema already provides. It does not contradict annotations.

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?

Two sentences with no filler. The core action and scope are front-loaded, and the use-case guidance is a single clause. Every word 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 read-only list tool with a rich output schema, full parameter documentation, and annotations covering safety, the description is nearly complete. The only minor gap is that it doesn't explicitly state when not to use it or mention pagination behavior, but those are covered by the schema and the tool's simplicity.

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 the schema already documents all three parameters (limit, offset, business_id). The description adds a small amount of context by mentioning the business filter implicitly ('this business'), but it does not add meaning beyond the schema. Baseline 3 is appropriate.

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 ('List') and resource ('KaiCalls agents on the authenticated account'), and it distinguishes itself from sibling tools by clarifying scope (account-level listing). It also adds a practical use case ('before setting anything up, to see whether this business already has a secretary answering its calls'), which makes the tool's purpose immediately clear.

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 gives a clear context for when to use the tool ('before setting anything up') and what question it answers ('whether this business already has a secretary answering its calls'). It does not explicitly name alternatives or exclusions, but the context is strong enough for an agent to select it over siblings like list_numbers or list_recent_calls.

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