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

With no annotations, the description carries the full burden. It does contribute two useful behavioral facts: the 20-active-link cap and that the call returns code and url. It omits permissions/auth, what happens when the cap is hit, and whether label is optional, leaving real 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 compact sentences, front-loaded with the action and followed by the constraint and return shape. No filler.

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 low-complexity tool with one optional parameter, the description covers purpose, a hard limit, and return values in lieu of an output schema. The main residual gap is the optionality of label and any auth requirement.

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 the single label parameter is fully documented with an example in the schema, so baseline is 3. The description adds nothing about the parameter, including that it is optional (0 required params), missing an easy opportunity.

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 ('Create a new tracked referral link') that an agent can readily distinguish from update_referral_link and get_referral_overview. It stops short of explicitly naming the sibling boundary, but the create/update split is self-evident.

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?

There is no explicit when-to-use guidance, no alternatives named, and no prerequisites beyond the incidental '(max 20 active)' note. The cap at least signals a precondition under which the call will fail, which is implied usage rather than stated guidance.

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