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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds the non-obvious plan-tier restriction, which the agent cannot see anywhere in the structured fields and which would otherwise cause a failing call.

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?

Three short sentences, front-loaded with the resource and followed immediately by the retrieval restriction. Every clause carries information: what it returns, what fields each record holds, and who can call it.

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?

With an output schema present, the description need not explain return shape, and it correctly stays out of that. Read-only status, plan gating and the searchable fields are all covered; only the absence of any guidance on result volume relative to 'limit' keeps it from a 5.

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 50%: 'q' documents search over names/GTINs, and 'limit' is self-evident from its default 25 and 1-100 bounds even without prose. The description adds no filtering or pagination semantics, so the description neither compensates for nor widens the gap — baseline 3.

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?

Specific verb (List) plus a precisely named resource (GS1 Digital Link products), with a clarifying gloss ('the codes that go on retail packaging') that separates it from list_qr_codes and list_code_kinds. It never explicitly names the sibling it is not, so it stops short of 5.

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?

'Business plan only' is a genuine eligibility gate an agent must check before calling, which is more than most list tools offer. However, there is no statement of when to use this versus get_product (single lookup) or list_qr_codes, so routing is left to inference from the name.

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