Get Subscription

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

The annotations already declare readOnlyHint=true, and the description does not contradict this. It adds behavioral context by specifying the returned subscription attributes and reinforcing that subscriptions are scoped per project, which goes beyond the annotation and helps the agent understand the result scope.

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 two sentences long, front-loads the core action, and every phrase adds meaningful information. There is no filler or repetition.

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, the description covers the main purpose, the data returned, and the per-project scope. Although the output schema is absent, the description lists the key return fields, making the tool usable. It does not explicitly handle edge cases like missing subscription, but given the simplicity and annotations, this is adequate.

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 input schema already provides a full description for projectId, including its optional behavior and fallback to the user's first project. The tool description adds no additional parameter-level detail beyond 'for a specific project', so the baseline score of 3 is appropriate given 100% schema coverage.

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 verb 'Retrieve' and the resource 'active subscription for a specific project', and it enumerates the returned fields (plan name, billing period, status, renewal date). This makes the tool's purpose unambiguous and distinct from siblings like list_plans or get_usage.

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 'Subscriptions are per-project' implies that this tool should be used when project-specific subscription details are needed, and it hints at a key constraint. However, it does not explicitly mention alternatives or when not to use this tool, leaving the usage context only implied.

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