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

Annotations already declare idempotentHint=true, destructiveHint=false, and openWorldHint=true, and the description enriches this: the link stays valid up to 3 days, the tool 'creates nothing billable and connects nothing by itself', and it warns not to claim WhatsApp is connected until status confirms. This adds auth and workflow constraints beyond the 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?

Front-loaded with the core purpose, then layers caveats and the follow-up step. It is dense and every sentence carries information, though slightly long and working hard to pack in constraints.

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?

An output schema exists so return values need no explanation. Combined with the auth requirements, line-selection default, validity window, and explicit next-step routing, the definition is complete for correctly invoking the tool.

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 coverage is 50%, with business_id undocumented. The description compensates for phone_number by explaining the default-to-oldest-line behavior, which the schema does not convey, though business_id's role remains implicit as the account scope.

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 and resource: 'Get the one link a business owner opens to put WhatsApp on their KaiCalls number.' It distinguishes itself from the sibling get_whatsapp_status by explicitly noting it 'connects nothing by itself' and pointing to the status tool afterward.

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?

Explicitly states who may call it ('Owner or admin only'), the default line selection ('oldest KaiCalls line unless phone_number names another'), and the follow-up requirement ('call get_whatsapp_status after the owner finishes'). When-to-use and the alternative flow are both spelled out.

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