> ## Documentation Index > Fetch the complete documentation index at: https://docs.agentscore.sh/llms.txt > Use this file to discover all available pages before exploring further. # x402 client compatibility > Which x402 / MPP / Tempo CLIs are verified to complete payments against AgentScore-built merchants. Updated reactively as we smoke-test new clients. If you're an agent (or a human testing a payment flow) and you want to know which CLI to use to pay an AgentScore-built merchant, this is the canonical list. Every entry has been smoke-tested end-to-end against a `@agent-score/commerce`–powered merchant. When a new client is verified, it gets added; when a verified client breaks, the row gets a note. Merchants built on `@agent-score/commerce` emit an `agent_instructions.compatible_clients` field on every 402 response and the same per-rail matrix in their static `/skill.md` discovery manifest; agents can read it inline (or fetch the manifest upfront) without ever loading this page. The 402 body, the skill manifest, and this docs page all source from the same SDK constant, so they don't drift. ## What works | Client | Tempo MPP | x402 Base | Solana MPP | Stripe SPT | Notes | | ----------------------------------------------------------------- | --------- | --------- | ---------- | ---------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **`agentscore-pay`** (npm: `@agent-score/pay`) | ✅ | ✅ | ✅ | : | Universal CLI, all native rails. Auto-injects `X-Wallet-Address` from keystore when no identity header is supplied. | | **`tempo request`** (Tempo CLI extension via `tempo add request`) | ✅ | : | : | : | MPP-only. Native to the Tempo CLI. | | **`x402-proxy`** (npm: `x402-proxy`, by Cascade) | ✅ | ✅ | : | : | Closest functional twin to `agentscore-pay` for x402-protocol rails. Doesn't speak MPP `solana/charge`. | | **`purl`** (Stripe purl) | ⚠️ | ✅ | : | : | Base x402 works **only when `--network` flag is omitted**. Tempo MPP fails on multi-rail `WWW-Authenticate` parsing. | | **`@stripe/link-cli`** | : | : | : | ✅ | MPP-native via Stripe Shared Payment Token. | | **`awal`** (Coinbase) | : | ❌ | : | : | awal pre-discovers via empty-body POST and never sends the request body, so per-order priced merchants like Martin Estate and Sayer & Stone can't surface their accepts to it. Works against fixed-price endpoints listed in Coinbase Bazaar. | Legend: ✅ verified end-to-end · ⚠️ partial / specific workaround · ❌ doesn't work today ·; not applicable to this rail. ## Recommended commands per rail **Tempo MPP** * `tempo request -X POST -H 'X-Operator-Token: opc_...' --json '{...}' ` * `agentscore-pay pay POST --chain tempo -H 'X-Operator-Token: opc_...' -d '{...}'` **x402 on Base** * `agentscore-pay pay POST --chain base -H 'X-Operator-Token: opc_...' -d '{...}'` * `purl -X POST -H 'X-Operator-Token: opc_...' -H 'Content-Type: application/json' -d '{...}'` *(no `--network` flag)* * `x402-proxy fetch -X POST -d '{...}' --evm-key --network base --protocol x402 ` **Solana via MPP `solana/charge`** * `agentscore-pay pay POST --chain solana -H 'X-Operator-Token: opc_...' -d '{...}'` **Stripe Shared Payment Token (Link wallet)** * `link-cli mpp pay --spend-request-id --method POST --data '{...}' --header 'X-Operator-Token: opc_...'` ## Why some clients don't fully work For the partial entries above, the failures come from client-side assumptions that don't fit the protocol shape AgentScore-built merchants emit. We share the diagnostics in case other ecosystem players want to reproduce or fix them: * **`purl --network` flag**: purl's negotiator compares the flag value (e.g. `base`) against the CAIP-2 string in the 402's `accepts[]` (e.g. `eip155:8453`) without normalizing aliases. With no flag passed, purl's filter short-circuits and it correctly picks the first compatible challenge. Workaround: omit the flag. * **`purl` Tempo MPP**: purl's MPP parser raises `Duplicate parameter: id` on multi-`Payment` `WWW-Authenticate` headers (one MPP directive per rail, comma-separated, per RFC 7235). Three other independent clients parse the same header correctly. * **`awal`**: pre-discovers payment requirements via empty-body HEAD/GET/POST/PUT/DELETE/PATCH, then signs against whatever it finds. Variable-priced merchants need the actual request body to compute per-order pricing + per-order deposit addresses, so awal can't discover anything to sign. Bazaar-registered fixed-price endpoints are awal's working surface today. ## Are funds at risk on a failed payment? No. x402 facilitators (Coinbase's, primarily) **simulate** transactions before broadcasting. A simulation failure doesn't broadcast, doesn't move USDC, doesn't consume gas. A signed-but-not-broadcast tx becomes inert when the `validBefore` window (EVM EIP-3009) expires, typically within minutes. Buyers can switch to a different client and retry without losing anything. ## How to add your client to this list Open the AgentScore-Solana / x402 partnership channel and run a smoke. We'll verify and add the entry. We don't accept self-reported entries; the matrix only lists what we've directly run. ## Last verified Most recent full smoke matrix against a multi-rail `/purchase` (402): `agentscore-pay` × Base/Solana/Tempo ✅, `tempo request` × Tempo ✅, `x402-proxy` × Base/Tempo ✅, `purl` (no flag) × Base ✅, `awal` ❌, `link-cli` × Stripe ✅ (separate flow).