whatsapp_get_qr_code

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds genuinely useful behavior beyond that: the logged-out precondition and the ~1 minute expiry window for each code, which materially affects call timing. It does not describe error behavior when called while logged in, keeping it short of a 5.

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, all earning their place: purpose, precondition, expiry, and two alternatives. Purpose and precondition are front-loaded ahead of the routing hints.

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 no-parameter tool with no output schema, the description covers what the return is ('the QR string'), when it is valid, and how long it lasts. An agent has everything needed to call it correctly and interpret timing.

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 tool takes zero parameters, so the baseline is 4. The description correctly notes the string return value and adds nothing spurious about nonexistent inputs.

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 login QR code as a text string') plus the reason ('to pair a phone with this instance'). It explicitly distinguishes itself from whatsapp_get_qr_code_image and whatsapp_get_pair_code, so an agent can route without opening schemas.

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?

Gives an explicit precondition ('Only works while logged out') and names both alternatives with the condition that selects each: image output vs pairing by phone number. Nothing is left to inference.

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