Get a pairing code

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

Beyond the annotations, it reveals the code's TTL ('lives about 160 seconds') and a specific failure mode (`already_linked`). The open-world, non-idempotent nature is consistent with the description, though other potential side effects are not detailed.

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 sentences each deliver distinct, useful information: purpose, code lifetime, and error condition. There is no filler, repetition, or extraneous detail.

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 two-parameter tool with no output schema, the description adequately explains the return value, the code lifespan, and the error behavior. It could be slightly more explicit about prerequisites or side effects, but nothing critical 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?

The input schema already documents both `phone` and `accountId` with 100% coverage. The description does not add significant parameter-specific meaning beyond the phone-based linking context, so a baseline score of 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 clearly states the resource (a pairing code) and the action: it links by phone number instead of QR code and returns an 8-character code. The contrast with QR code also distinguishes it from the sibling get_account_qr_code.

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?

It provides a clear usage context: use this tool when linking via phone number instead of a QR code. It does not explicitly name the alternative tool or list exclusions, but the 'instead of QR code' framing gives enough guidance.

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