Move a subscription to another plan: upgrades charge now, downgrades apply at period end. Handles prorated billing for plan changes.
Move a subscription to another plan (upgrade charges now, downgrade at period end)
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | The subscription id | |
| to | Yes | Target plan: the product id (same currency and interval) | |
| dryRun | No | Show the quote only; apply nothing |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It discloses key billing semantics: upgrades charge immediately and downgrades take effect at period end. That is meaningful beyond the schema, though it omits permission requirements, reversibility, and response behavior.
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?
A single short sentence, front-loaded with the action and resource, with zero filler. The parenthetical adds the one behavioral nuance that matters most.
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 100% schema coverage and no output schema, the description supplies the essential mutation behavior and billing timing. It could mention dryRun or response shape more directly, but for a three-parameter plan-change tool the core information is present.
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 already documents all three parameters at 100% coverage, including id, to, and dryRun. The description only implies the 'to' field via 'another plan' and adds no format or constraint details beyond the schema.
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?
States a specific verb ('Move') and resource ('subscription') and identifies the target as 'another plan', which differentiates it from cancel/list siblings in the toolset. It does not name any sibling or explicitly contrast, so not a 5.
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 purpose makes the general use case obvious, and upgrade/downgrade timing hints at behavior, but there is no explicit when-to-use guidance or comparison to sibling tools like subscriptions_cancel. No exclusions or prerequisites are stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.