zas_pair

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

No annotations exist, so the description carries the whole burden, and it does disclose the important non-obvious traits: this is a multi-call asynchronous owner-approval handshake, re-pairing in an existing profile replaces the prior agent, and the owner sees this agent's mark and name on every device. It stops short of stating code expiry, rate limits, or what the first response contains besides a URL.

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?

Four short sentences, the action and the flow front-loaded with the conditional `code` case placed where the agent will need it. The closing sentence on the agent mark is mild extra detail but earns its place as visible-behavior disclosure.

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 one-optional-param pairing tool with no output schema and no annotations, the description covers the full interaction shape: initiation, polling, code fallback, and re-pairing semantics. Only the absence of any timeout or expiry guidance keeps it from being fully complete.

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 schema already documents `code` at 100% coverage, and the description adds why it exists: it is the fallback for when the browser cannot reach this machine. That contextualizes a parameter an agent might otherwise supply blindly, though it doesn't give format specifics.

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?

Opens with a specific verb and resource: 'Pair this agent with a Zas account.' That is unmistakably distinct from the send/receive/status siblings, which all operate on already-paired data. An agent can pick this tool without opening the schema.

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?

Lays out the call sequence clearly: first call yields a URL for the owner, a later call reports approval, and a `code` argument is only needed when the page shows one. What's missing is any routing versus siblings (e.g. check zas_status first, or what to do if the profile is already paired beyond 'replaces the old agent').

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