auth_qr

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

With no annotations provided, the description carries the full behavioral burden. It does disclose a genuine side effect — the QR is 'also printed on stderr' — which is useful because agents may otherwise rely only on the return value. However, it does not reveal other behavioral traits such as whether a new pairing session is initiated, whether QRs expire, or what happens when already authenticated.

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?

Two short sentences with no filler. The first delivers the core action plus the stderr side-effect; the second gives the human-action follow-through. Every word earns its place and the key content is front-loaded.

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 zero-parameter utility with no annotations and no output schema, the description is largely sufficient: it names the return value (the QR), the side channel (stderr), and the expected downstream user action. The only minor gap is that it never states the return format of the QR or failure behavior, but the tool's simplicity keeps this from being a significant omission.

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 has zero parameters and 100% schema coverage, so the description need not document inputs. 'Get the latest' adds the meaningful semantic that the tool returns the most recent QR rather than generating a fresh session, which is the only invocation-relevant detail an agent needs when there are no arguments.

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 states a specific verb and resource: 'Get the latest WhatsApp pairing QR.' It clearly identifies what the tool produces and adds the user-facing purpose ('Scan with WhatsApp > Linked Devices'), which removes any ambiguity against the sibling list — no other sibling is about pairing or authentication.

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 context of use is implied: this tool is for obtaining a QR to pair a new WhatsApp-linked device, reinforced by the scanning instruction. However, there is no explicit statement of when to use it versus alternatives, when not to use it, or any prerequisite such as being in an unauthenticated state — the guidance is present but only by implication.

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