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

Annotations only provide the generic safe-write profile (readOnly=false, destructive=false). The description adds real behavioral facts annotations cannot carry: selectionType and allowQuantity are immutable after creation, allowQuantity is rejected on non-'multiple' types, and modifier names must be unique per merchant ignoring case.

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?

The most consequential warning (the tool alone does nothing) is front-loaded, followed by the irreversible selectionType decision and then the conditional allowQuantity rule. Every sentence carries a constraint the agent cannot infer from structured fields; nothing is padding.

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 create operation with no output schema, the description covers creation semantics, the chaining requirement and immutability constraints very well, but never states what is returned (notably the new modifier id needed by link_modifier_to_category). That is a minor but real gap in an otherwise complete definition.

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 meaningfully exceeds the schema by defining each enum value with concrete examples ('single' = milk/temperature, 'multiple' = toppings, 'multiple'+allowQuantity = tick and count, 'quantity' = steppers) and by clarifying that the last two count units rather than distinct choices — information absent from the bare enum list.

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+resource ('Create a new question the till can ask, with its choices') and immediately distinguishes itself from hub_add_modifier_choice and hub_create_product_option by scoping to the whole modifier rather than a later-added choice. An agent knows exactly what object is being produced.

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?

Explicitly names the required follow-up ('follow it with link_modifier_to_category, or the modifier sits unused'), which is the single most important routing fact for this tool. It also implicitly routes choice-by-choice authoring to the add-choice flow via the schema note, so the agent has both when-to-use and when-not-standalone guidance.

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