get_subscription

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explicitly states 'Read-only', which is a key safety trait. It does not cover errors or authentication, but for a simple fetch operation this is sufficient.

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 a single, front-loaded sentence that delivers the essential information: what it does, how, and the read-only nature. No wasted words.

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-fetch tool with one well-documented parameter and no output schema, the description covers the purpose, input, and safety. It could be slightly more explicit about the output, but 'Fetch a single recurring subscription' implies the return value, making it sufficiently complete.

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 covers 100% of the parameter, and the parameter description already explains 'The recurring subscription ID to look up'. The tool description merely repeats this with 'by its subscription ID', adding no new semantic value beyond what the schema provides.

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 'Fetch a single recurring subscription by its subscription ID', using a specific verb and resource. It distinguishes itself from sibling tools like get_transaction and list_subscriptions by targeting a single recurring subscription.

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 provides clear context for when to use the tool: when a specific recurring subscription ID is known. It does not explicitly mention alternatives or exclusions, but the 'report_type=recurring' hint and the singular nature imply when it is appropriate compared to list_subscriptions.

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