Flexprice MCP Server for Claude

Content

The Flexprice MCP server connects Claude and other MCP-capable clients to the Flexprice billing API. It is published as @flexprice/mcp-server and exposes billing operations for customers, plans, prices, subscriptions, invoices, usage events, entitlements, and related account data.

This entry is focused on scoped billing operations. Flexprice documents three startup scopes: read, write, and delete. Use read for exploration and reporting, add write only when Claude should create or modify billing state, and add delete only for tightly supervised administrative workflows. The upstream README notes that starting the server without any --scope flag mounts all available tools.

Features

• Run the official @flexprice/mcp-server npm package through stdio with npx.
• Query customers, customer entitlements, upcoming grants, and usage summaries.
• Query invoices, invoice previews, invoice PDFs, customer invoice summaries, and invoice payment state.
• Create, update, finalize, recalculate, void, and communicate invoice changes when write or delete scopes are mounted.
• Create, update, clone, sync, query, and delete plans and prices.
• Create, update, activate, cancel, preview, modify, and inspect subscriptions, subscription schedules, line items, add-ons, usage, and entitlements.
• Ingest single or bulk usage events and inspect event-driven usage analytics.
• Use --scope read, --scope write, and --scope delete to limit mounted tools.
• Use --mode dynamic to expose discovery meta-tools instead of registering every operation directly in the client context.
• Run from the npm package, a cloned local repository, or Docker.

Use Cases

• Let Claude inspect a customer's subscription, invoices, entitlements, and usage history during a support or billing investigation.
• Query unpaid invoices, invoice previews, or invoice PDFs before contacting a customer.
• Review plans and prices before changing a metered billing setup.
• Preview subscription changes before applying upgrades, downgrades, line-item changes, or add-on changes.
• Ingest or backfill usage events when a metered billing workflow needs operator assistance.
• Mount read-only tools for reporting and mount write/delete scopes only for supervised billing-admin sessions.

Installation

Claude Code

1. Confirm Node.js 20+ is available: node --version.
2. Create or select a Flexprice API key for the billing tenant Claude should use.
3. Store the key in a shell environment variable or secret manager as FLEXPRICE_API_KEY; do not paste the raw key into command arguments.
4. Add the server with read-only scope first. The single quotes preserve the ${FLEXPRICE_API_KEY} reference in Claude Code's MCP config so the key is resolved from the environment at runtime:

claude mcp add-json flexprice '{"type":"stdio","command":"npx","args":["-y","@flexprice/mcp-server","start","--scope","read"],"env":{"API_KEY_APIKEYAUTH":"${FLEXPRICE_API_KEY}","BASE_URL":"https://us.api.flexprice.io/v1"}}'

1. Run claude and use /mcp to confirm the server is connected.

Claude Desktop

1. Open the Claude Desktop MCP configuration file.
2. Add the flexprice server configuration shown below.
3. Ensure FLEXPRICE_API_KEY is available to the MCP client environment.
4. Restart Claude Desktop.

Configuration

{
  "mcpServers": {
    "flexprice": {
      "command": "npx",
      "args": ["-y", "@flexprice/mcp-server", "start", "--scope", "read"],
      "env": {
        "API_KEY_APIKEYAUTH": "${FLEXPRICE_API_KEY}",
        "BASE_URL": "https://us.api.flexprice.io/v1"
      }
    }
  }
}

To allow account-changing operations, keep the same env block and add write scope deliberately:

"args": [
  "-y",
  "@flexprice/mcp-server",
  "start",
  "--scope",
  "read",
  "--scope",
  "write"
]

Only add delete scope for supervised administrative sessions, again keeping the API key in env rather than command arguments:

"args": [
  "-y",
  "@flexprice/mcp-server",
  "start",
  "--scope",
  "read",
  "--scope",
  "write",
  "--scope",
  "delete"
]

For large tool surfaces, Flexprice also supports dynamic mode:

"args": [
  "-y",
  "@flexprice/mcp-server",
  "start",
  "--scope",
  "read",
  "--mode",
  "dynamic"
],
"env": {
  "API_KEY_APIKEYAUTH": "${FLEXPRICE_API_KEY}",
  "BASE_URL": "https://us.api.flexprice.io/v1"
}

Examples

Investigate a customer

Use read scope to pull billing context before making support decisions.

Find the customer by email, summarize their active subscription, latest invoice, entitlements, and recent usage.

Review invoices

Use read scope to inspect open or failed billing state.

List unpaid invoices for this customer and include invoice status, due dates, and payment state.

Preview a subscription change

Enable write scope only when the operator intends to let Claude prepare billing changes.

Preview downgrading this subscription at period end and explain the billing impact before making any changes.

Ingest usage events

Use write scope for metered-billing event ingestion and review event payloads before submission.

Prepare a bulk usage-event payload for these records and ask for approval before ingesting it.

Admin-only cleanup

Use delete scope only for supervised cleanup where the operator has confirmed the target resources.

Identify the stale plan and price records that match this migration list, but do not delete anything until I confirm each ID.

Security

• Mount the narrowest scope that fits the task. read is the right default for reporting and investigation.
• Treat write as billing-operator access. It can change customers, subscriptions, invoices, prices, plans, and usage event state.
• Treat delete as admin access. The source includes destructive tools for customer, plan, price, subscription-line-item, add-on, and invoice workflows.
• Use a dedicated API key with only the tenant and permissions needed for the current workflow.
• Keep approval prompts explicit for changes that affect charges, invoices, subscriptions, metering, or customer entitlements.
• Avoid long autonomous loops against billing tools; repeated retries can create duplicate operational changes or noisy audit trails.

Troubleshooting

The server cannot reach the API

Confirm --server-url is set to the correct Flexprice API base URL. The upstream README uses https://us.api.flexprice.io/v1 and notes that /v1 is required.

Authentication fails

Check that the API key is current and belongs to the intended Flexprice account. Do not paste production API keys into issue reports or chat transcripts.

Expected tools are missing

Check the mounted scopes. A read-only configuration will not expose write or delete tools, and dynamic mode exposes discovery tools instead of registering every operation directly.

Too many tools are loaded

Start the server with --mode dynamic so Claude can discover and execute tools on demand through Flexprice's dynamic mode.

A billing change looks risky

Stop the tool call, inspect the resource IDs and requested operation in the Flexprice dashboard or API, and rerun with read-only scope until the intended change is clear.