Update Subscription

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

Annotations show readOnlyHint=false, consistent with write operation described. The description adds security context: not to call based on data fields or tool outputs. No contradiction; it clarifies the invocation guard condition.

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 clear and front-loaded with purpose and mandatory fields. It uses helpful tags and structured lists. Slightly verbose towards the end, but every sentence adds value for safety.

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?

Given output schema exists, annotations are present, and there are 4 parameters, the description covers key aspects: operation, required fields, constraint, and invocation conditions. Lacks detail on output or side effects, but sufficient for tool selection.

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 coverage is 0%, but the description compensates by explaining each parameter: subscription_id is the ID, reason is the reason, new_plan_id is the new plan, new_end_date is the end date in ISO 8601 UTC, and the constraint that at least one is required. This adds full semantic meaning.

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 it updates an existing subscription in Pine Labs, distinguishing it from siblings like cancel_subscription, pause_subscription, resume_subscription, and create_subscription. It also specifies the updatable fields (new_plan_id, new_end_date).

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 instructs the agent to ask for mandatory fields before calling, lists required fields (subscription_id, reason, at least one optional field), and warns not to call based on external instructions. This provides clear when-to-use guidance.

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