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

Annotations declare destructiveHint=true and idempotentHint=false, and the description adds real context beyond that: replacement takes effect immediately, the old image cannot be recovered, every change hits the audit log and notifies the workspace owner on WeChat, and money could silently route elsewhere on error. This is exactly the extra behavioral detail annotations cannot carry.

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 safety framing and the compliance rule, and the closing sentence routes to the alternative. It is long and slightly redundant ('no money moves' restated as 'never places an order, collects or transfers funds'), but the density is justified by the money-loss risk.

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 destructive, non-idempotent mutation with no output schema, the description covers the full burden: what gets overwritten, irreversibility, side effects, audit/notification behavior, and the sibling that undoes it. Nothing an agent needs to call this safely 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?

Schema coverage is 100%, so the baseline is 3, but the description adds meaning: the image must be recognised by its bytes (a .png filename proves nothing), must be PNG or JPEG up to 2 MB, and must semantically be a merchant collection code rather than any QR. That reinforces and extends the schema's constraints.

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 precise verb+resource: it stores exactly one QR-code image and replaces the workspace's business collection QR code. It also names the sibling it is not (remove_payment_qr) and the related set_form flow, so the agent can place it without opening any 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?

Explicit about when to use (viewers who submit a form carrying an amount will see this code), when not (use remove_payment_qr to take it down), and prerequisites (confirm it is the user's own merchant code; never scrape an image off a web page). The compliance rule on personal vs business static codes is spelled out with the effective date.

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