Begin a new Pro or Scale subscription for the project owner. Returns {checkoutUrl, plan} — surface the URL to the human for approval. Errors if the owner is already on an active paid plan (use change_plan instead). Owner-only; requires a token minted with the billing scope.
| Name | Required | Description | Default |
|---|---|---|---|
| plan | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the annotations (readOnlyHint=false, destructiveHint=false), the description discloses key behaviors: it returns a checkoutUrl for human approval, errors on existing subscriptions, and requires billing-scoped tokens. This adds meaningful context about the flow and prerequisites without contradicting annotations.
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 three sentences, front-loaded with the main action. Every sentence adds value: purpose, output, error condition, alternative, and access requirements. 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?
Given the simple schema (1 enum param, no output schema), the description is complete. It explains what the tool does, what it returns, when it fails, the alternative, and authorization requirements. Nothing critical is missing.
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% for the single 'plan' parameter. The description compensates by naming the valid values ('Pro or Scale') and mapping them to the subscription tier. It doesn't explicitly state that the parameter is 'plan' or that it is the only parameter, but the schema already provides the enum and required field, so the added semantics are sufficient.
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 ('Begin') and resource ('Pro or Scale subscription'), clearly stating the tool's function. It distinguishes from sibling tools by explicitly mentioning change_plan as an alternative when the owner is already on a paid plan.
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 explicit when-to-use guidance ('Begin a new Pro or Scale subscription'), when-not-to-use ('Errors if the owner is already on an active paid plan'), and the alternative tool ('use change_plan instead'). It also states prerequisites (Owner-only, requires a token with billing scope), giving clear context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Most tools target distinct resources and the descriptions are unusually explicit, but the billing cluster (change_plan/cancel_subscription and the many add-on actions) plus the preview/diff tools overlap and could cause mis-selection. config_diff, dry_run_endpoint, and preview_line_draft all read as 'preview what will change' at first glance despite different scopes.
The overwhelming majority follow a clean snake_case verb_noun pattern: create_*, get_*, list_*, set_*, update_*, delete_*. It is only held back by a few naming outliers such as config_diff and default_endpoint_template, which break the verb-first convention.
78 tools is an extreme mismatch for an MCP server surface, even accounting for the broad management/relay domain. Such a large surface will overwhelm model context and make tool selection materially harder; this would be better split into focused servers for configuration, data-plane operations, and billing.
The tool surface is very thorough: projects, lines, endpoints, credentials, keys, configs/drafts, DLQ, requests, metrics, audit, team, and billing are all represented. Only minor gaps exist, such as no direct single-line get/update and the intentional inability to widen the outbound allowlist or lift archive protection via API.
