Renew a device subscription by buying a package. Specify the device and package to extend its service.
Renew a device subscription by buying a package for it.
| Name | Required | Description | Default |
|---|---|---|---|
| device_id | Yes | Device to renew | |
| package_id | Yes | Renewal package. See list_packages. | |
| voucher_code | No | Optional voucher code |
Changes observed during successful MCP inspections.
v1.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure, but it only states the basic action. It omits important behavioral traits such as whether this causes a financial charge, extends the subscription from the current expiry date, or returns confirmation data. The phrase 'buying a package' hints at a purchase, but significant ambiguity remains.
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, direct sentence with no filler or redundant repetition. It communicates the core action efficiently and is appropriately front-loaded.
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?
This is a three-parameter mutation tool with no annotations and no output schema, yet the description only covers the basic purpose. Missing context includes prerequisites (active device, existing subscription), the meaning of a renewal package, potential side effects such as billing, and what response to expect.
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 100%, so the parameters are already documented in the input schema. The description adds no additional meaning beyond what the schema provides, and does not clarify how voucher_code interacts with the renewal flow.
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 uses a specific verb ('renew') and resource ('device subscription'), and clarifies the mechanism ('by buying a package'). It clearly differentiates this tool from siblings like create_device or device_status, since renewal is a distinct lifecycle operation.
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?
No guidance is given for when to use this tool versus alternatives. It does not mention that create_device is for new devices, that list_packages should be consulted before selecting a package, or any conditions under which renewal is applicable.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.