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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, covering safety. The description adds the specific return fields and status values (ACTIVE/EXPIRED/SCHEDULED), which go beyond annotations and help the agent understand the output shape.

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 brief and front-loaded with the main action, followed by usage guidance. However, the trailing 'Routing: Shopify discounts: title/type/status for codes and automatic discounts' line is redundant and adds noise, slightly reducing conciseness.

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 read-only listing tool with fully documented parameters and no output schema, the description provides sufficient context: what it lists, what fields are returned, and when to use it. Nothing critical 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 description coverage is 100% for both parameters (companyId and limit). The description does not add parameter-specific details beyond the schema, so it relies on the schema. Baseline of 3 is appropriate.

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 clearly states the tool lists discount codes and automatic discounts from the Shopify store, including specific fields (id, discount type, title, status). It also provides a usage context ('before creating or referencing one'), making the purpose unmistakable.

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 explicitly says 'Use to see what promotions currently exist before creating or referencing one,' giving a clear when-to-use context. It does not explicitly list alternatives or exclusions, but the intent is clear for a read-only listing tool.

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