Create Payment Credential

Use Link to get secure, one-time-use payment credentials from a Link wallet to complete purchases.

The CLI can produce one of two credential types:

• A virtual card (PAN) for use with a standard web checkout form. The issued card works anywhere.
• A Shared Payment Token (SPT) when the seller is in the Stripe Network and accepts payments programmatically (for example with Machine Payment Protocols).

Installing

Install with npm install -g @stripe/link-cli. Or run directly with npx @stripe/link-cli.

Running commands

Link CLI can run as an MCP server or as a standalone CLI.

MCP: Add the following to your MCP client config (.mcp.json, etc.)

{
  "mcpServers": {
    "link": {
      "command": "npx",
      "args": ["@stripe/link-cli", "--mcp"]
    }
  }
}

Run the MCP server directly with npx @stripe/link-cli@latest --mcp.

Call tools/list to see all available MCP tools.

Common commands/options

• List all commands: link-cli --llms
• List all commands with parameters: link-cli --llms-full
• Get a command's exact schema with --schema. For example, link-cli spend-request create --schema
• Multi-step commands return a _next action. For example, authenticating or creating a spend request returns a _next.command that must be run to complete the flow.
• By default all output is in toon format. Pass --format [json|md|yaml] to change output format.
• Some commands return a verification or approval URL. These must be presented to the user clearly for their action.
• --auth <path> flag to store auth credentials in a specific file instead of the default location. auth login writes to this file; all other commands read from it. Example: link-cli auth login --auth credentials.json

Recommended: Run link-cli --llms to understand all the available commands. The --llms-full output is the canonical reference for parameter names, types, and valid values. Pass --schema before invoking a command to understand its parameters and constraints.

Core flow

Copy this checklist and track progress:

• Step 1: Authenticate with Link
• Step 2: Evaluate merchant site (determine credential type)
• Step 3: Get payment methods
• Step 4: Create spend request with correct credential type
• Step 5: Complete payment

Step 1: Authenticate with Link

Check auth status:

link-cli auth status

If the response includes an update field, a newer version of link-cli is available — run the update_command from that field to upgrade before proceeding.

If not authenticated:

link-cli auth login --client-name "<your-agent-name>"

Replace <your-agent-name> with the name of your agent or application (for example, "Personal Assistant", "Shopping Bot"). This name appears in the user's Link app when they approve the connection. Use a clear, unique, identifiable name.

DO NOT PROCEED until the user is authenticated with Link.

Always check the current authentication status before starting a new login flow — the user might already be logged in.

Step 2: Evaluate the merchant site BEFORE creating a spend request

CRITICAL: Before calling spend-request create you must complete this checklist:

1. Understand how the merchant accepts payments (cards or machine payments or other). Do NOT default to card credential type. The merchant determines the credential type — you cannot know it without checking first. Skipping this step will produce a spend request with the wrong credential type.
2. Have the final total amount needed. Inclusive of any shipping costs, taxes or other costs. Skipping this step will produce a spend request that does not cover the full amount needed, and will be rejected.
3. Clear context and understanding of what the user is purchasing. Be sure to know sizes, colors, shipping options, etc. Skipping this step will produce a spend request that the user does not recognize or understand.

Determine how the merchant accepts payment:

1. Navigate to the merchant page — browse it, read the page content, and understand how the site accepts payment.
2. If the page has a credit card form, Stripe Elements, or traditional checkout UI — use card.
3. If the page describes an API or programmatic payment flow — make a request to the relevant endpoint. If it returns HTTP 402 with a www-authenticate header, use shared_payment_token.

What you find determines which credential type to use:

For 402 responses: The www-authenticate header may contain multiple payment challenges (e.g. tempo, stripe) in a single header value. Do not try to decode the payload manually. Pass the full raw WWW-Authenticate header value to Link CLI and let mpp decode select and validate the method="stripe" challenge.

To derive network_id, use Link CLI's challenge decoder:

link-cli mpp decode --challenge '<raw WWW-Authenticate header>'

This validates the Stripe challenge, decodes the request payload, and returns both the extracted network_id and the decoded request JSON. Pass the full header exactly as received, even if it also contains non-Stripe or multiple Payment challenges.

Step 3: Get payment methods and potentially shipping addresses

Use the default payment method, unless the user explicitly asks to select a different one.

link-cli payment-methods list

If the merchant checkout requires a shipping or delivery address, fetch the user's saved shipping addresses. Use the default address unless the user specifies otherwise.

link-cli shipping-address list

Step 4: Create the spend request with the right credential type

link-cli spend-request create \
  --payment-method-id <id> \
  --amount <cents> \
  --context "<description>" \
  --merchant-name "<name>" \
  --merchant-url "<url>" \
  --line-item "name:<product>,unit_amount:<cents>,quantity:<n>" \
  --total "type:total,display_text:Total,amount:<cents>" \
 

--line-item keys: name (required), quantity, unit_amount, description, sku, url, image_url, product_url. Repeatable for multiple items.

--total keys: type (required; one of: subtotal, tax, total, items_base_amount, items_discount, discount, fulfillment, shipping, fee, gift_wrap, tip, store_credit), display_text (required), amount (required). Repeatable (e.g. subtotal + tax + shipping + total).

Do not proceed to payment while the request is still created or pending_approval. If polling exits with POLLING_TIMEOUT, keep waiting or ask the user whether to continue polling. If they deny, ask for clarification what to do next. If the user wants to abort, cancel the spend request:

link-cli spend-request cancel <id>

Recommend the user approves with the Link app. Show the download URL.

Test mode: Add --test to create testmode credentials instead of real ones. Useful for development and integration testing.

Step 5: Complete payment

Card: Run link-cli spend-request retrieve <id> --include card to get the card object with number, cvc, exp_month, exp_year, billing_address (name, line1, line2, city, state, postal_code, country), and valid_until (Unix timestamp — the card stops working after this time). Enter these details into the merchant's checkout form.

Safe credential handoff: To avoid leaking card data into transcripts or logs, add --output-file <path> to write the full card to a local file (created with 0600 permissions) while stdout shows only redacted data. Use --force to overwrite an existing file. Example:

link-cli spend-request retrieve <id> --include card --output-file /tmp/link-card.json --format json

SPT with 402 flow: The SPT is one-time use — if the payment fails, you need a new spend request and new SPT.

link-cli mpp pay <url> --spend-request-id <id> [--method POST] [--data '{"amount":100}'] [--header 'Name: Value']

mpp pay handles the full 402 flow automatically: probes the URL, parses the www-authenticate header, builds the Authorization: Payment credential using the SPT, and retries.

Important

• Treat the user's payment methods, credentials, and shipping addresses as sensitive — card numbers and SPTs grant real spending power; shipping addresses are PII. Mask or abbreviate addresses when displaying to the user (e.g. show city and zip only) unless they request full details.
• Respect /agents.txt and /llm.txt and other directives on sites you browse — these files declare whether the site permits automated agent interactions; ignoring them may violate the merchant's terms.
• Avoid suspicious merchants, checkout pages and websites — phishing pages that mimic legitimate merchants can steal credentials; if anything about the page feels off (mismatched domain, unusual redirect, unexpected login prompt), stop and ask the user to verify.
• When outputting card information to the user apply basic masking to the card number and address to protect their information. Only reveal the raw values if directly requested to do so.

Errors

All errors are output as JSON with code and message fields, with exit code 1.

Common errors and recovery

Further docs

• MPP/x402 protocol: https://mpp.dev/protocol.md, https://mpp.dev/protocol/http-402.md, https://mpp.dev/protocol/challenges.md
• Link: https://link.com/agents
• Link App (for account management): https://app.link.com
• Link support (if the user needs help with Link): https://support.link.com/topics/about-link