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

With annotations already declaring readOnlyHint=false and openWorldHint=true, the description still adds meaningful context: the default confirm-each-call behavior (which can be switched off), the requirement to confirm with the user before reaching other people, the need for a Cotlet API key with app access, and the business rule that Teachable does not sell paid products below $1.00 USD. This goes well beyond the annotations.

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 purpose is front-loaded, which is good, but the body is a series of short fragments with some redundancy against the schema (repeating the letters/numbers-only rule) and the confirmation guidance is split across two sentences. It is readable but not tightly edited.

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?

There is no output schema, and the description covers the creation scope, constraints, confirmation protocol, and auth requirement, which is most of what an agent needs. It stops short of describing what the created coupon returns or how applies_to interacts with pricing_plan_id, leaving a small gap for an 8-parameter mutation tool.

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 description coverage is 100%, so the baseline is 3. The description largely restates schema facts (code is letters/numbers only, quantity up to 10,000) and adds one genuine business rule (no paid product below $1.00 USD) that is not in the schema, but it does not explain discount_type vs discount semantics or pricing_plan_id's conditional requirement.

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 ('Creates a coupon on the Coupons page') and clarifies the scope options (all products, one product type, or one pricing plan). It distinguishes creation from the sibling list/archive coupon tools, though the opening fragment ('Teachable: Coupon code for all products...') is awkwardly phrased rather than a clean purpose statement.

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?

Usage is implied by the verb 'creates' versus sibling tools like teachable_list_coupons and teachable_archive_coupon, and the confirmation protocol is described. However, there is no explicit statement of when to use this tool rather than listing or archiving, nor any prerequisites for setup beyond the API key note.

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