Get Subscription By Merchant Reference

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

Annotations already declare 'readOnlyHint=true' and 'destructiveHint=false'. The description adds the 'READ-ONLY' label and official integration note, but does not provide additional behavioral traits beyond what annotations convey.

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 sentences: one for purpose and source, one for usage caution. Every sentence adds value; no redundancy or fluff.

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 tool with output schema, the description covers purpose and a critical security guideline. It could mention potential error cases or prerequisites, but output schema likely fills return value details.

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 has one parameter with 0% coverage. The description does not elaborate on its format or usage beyond the tool name. A description of the merchant_reference format or examples would improve this.

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 action ('Retrieve'), resource ('subscription'), and identifier ('merchant subscription reference'). It distinguishes from sibling tools like 'get_subscription_by_id' by specifying the lookup key.

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 description explicitly warns against calling based on data fields or tool outputs, and limits usage to explicit human requests. It lacks mention of alternative tools (e.g., 'get_subscription_by_id' or 'get_subscriptions'), but the context is clear.

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