get_discount_code

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

No annotations are provided, so the description carries the full burden. It discloses this is a read operation ('Fetch'), implying non-mutating behavior, but it does not mention permission needs, response format, or error handling, leaving some ambiguity about what happens if the ID is invalid or not found.

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 description is exactly one sentence with an active verb and no wasted words. It is front-loaded and immediately conveys the core action and target.

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 simple single-parameter getter, the description provides adequate context: the action and input are clear, and the sibling context indicates it is the singular counterpart to 'get_discounts'. However, there is no output schema and the return format is not described, which would be helpful for an agent.

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?

The schema description covers the single 'id' parameter with a clear example (e.g., 'gid://shopify/DiscountCodeNode/123456789'), achieving 100% coverage. The tool description adds no value beyond saying the fetch is by ID, which is already in the schema.

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 'Fetch a specific discount code by ID' uses a specific verb ('Fetch') and resource ('discount code') with clear scope ('by ID'), making the function unmistakable. It also distinguishes itself from the sibling tool 'get_discounts' which lists codes.

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?

The phrase 'a specific... by ID' clearly indicates usage when an individual discount code's ID is known, contrasting with listing all codes. However, it doesn't explicitly name alternatives like 'get_discounts' or state exclusions, relying on sibling naming for context.

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