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

With no annotations, the description carries the full behavioral burden. It usefully discloses the auth prerequisites (FixedQR API key, active plan), but says nothing about failure modes, whether edits break existing scans, or whether changes are reversible — meaningful gaps for a mutation tool.

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 tight sentences, front-loaded with the action and followed by prerequisites. No filler, though it could have used a few of those words to clarify the id parameter.

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 mutation tool with no annotations, no output schema, and 0% parameter coverage, the description is thin: it omits what 'id' identifies, whether label/target are both optional, and what the result of an update looks like. Auth context is present but insufficient overall.

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 0% across 3 parameters, so the description must compensate and only partly does. It implies 'label' and 'target' semantics via 'label'/'destination', but the mismatch ('destination' vs schema's 'target') risks confusion, and the required 'id' parameter is never explained.

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: 'Change the destination or label of an editable QR code you own.' This distinguishes it from create_dynamic_code and generate_qr by scope (modify vs. create/generate), though it doesn't name the siblings explicitly.

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?

'an editable QR code you own' plus the plan/API key requirement implies when the tool is applicable, but there is no explicit when-not guidance or reference to an alternative (e.g., use create_dynamic_code for new codes). Usage must be inferred.

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