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

Beyond the annotations it discloses the two behaviors that matter: the result is a link for the CUSTOMER to click, not a completed transaction, and the `items` path is validated against the live catalog (so invalid SKUs surface as errors). That adds real context the annotations don't convey. It does not explain what happens when the goal/preferences match no set, or what the returned link looks like.

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: what it builds, the optional item-form alternative, then the key non-mutation caveat. The most decision-relevant constraints are front-loaded and nothing is redundant.

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 five-parameter link-generator with no output schema, the definition supplies what an agent needs: required vs optional inputs, the enum vocabularies via schema, catalog validation behavior, and the fact that the return value is a URL rather than an order. Nothing material 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% and four parameters are enums with their own descriptions, so the schema already carries most of the meaning. The description restates the preference names (zestaw, moc, forma) and the SKU:quantity format without adding syntax or constraint detail beyond the schema. Baseline 3 applies since the description adds little param-level value.

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 ("Builds a link"), the resource (the subscription builder at /subskrypcja/zestaw), and the inputs it derives from (goal plus optional preferences). The closing sentence explicitly separates it from a purchase action ("Does NOT create a subscription or pay"), so an agent can distinguish it from zloz_subskrypcje or place_order without opening a 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?

It gives clear usage context: use it to produce a clickable link for the customer, including the alternative path of passing explicit items. The negative guidance ("does NOT create a subscription or pay") effectively steers the agent away from the ordering siblings. It stops short of naming the sibling to use when the customer actually wants to complete checkout, leaving that inference to the agent.

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