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 valuable behavioral context: it returns the A-du page, reports verification status, and clarifies that the assistant cannot complete the application. It doesn't mention side effects like whether starting an application creates a record, but the idempotentHint and readOnlyHint cover the main concerns.

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 sentences with zero waste. The core action is front-loaded, the return value is stated, and the critical limitation (assistant cannot complete) is included. 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 tool with one optional parameter, no output schema, and annotations covering safety, the description is nearly complete. It explains what the tool does, what it returns, and the key limitation. The only minor gap is not describing the exact structure of the A-du page or what 'already verified' means in practice, but that's not necessary for correct invocation.

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 the single optional parameter (listing_id). The description adds context by explaining why the parameter exists ('so the link returns them to it'), which is helpful but not essential. Baseline 3 is appropriate since the schema does the heavy lifting.

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 clearly states the verb ('Begin'), the resource ('a rental application'), and the actor ('for the signed-in person'). It also distinguishes itself from siblings by noting it returns the A-du page and reports verification status, which separates it from tools like request_tour or send_inquiry.

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 explicitly states when to use this tool (to begin a rental application) and provides a clear exclusion: an assistant cannot complete an application because identity verification and background-check authorization require the person themselves. This gives the agent actionable guidance on when not to use it or what to delegate.

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