Detects whether a 402 is MPP or x402 and loads the matching protocol playbook end-to-end.
Read ../okx-agentic-wallet/_shared/preflight.md before any onchainos command. EVM only — CAIP-2 eip155:<chainId> (run onchainos wallet chains for the list).
MPP mid-session ops (close / topup / settle / voucher / refund mentioned with an active channel_id, regardless of fresh 402) → stay here, load protocols/mpp.md, jump to the matching phase. Do NOT search for a separate close-channel / topup-channel / settle-channel tool — they're all onchainos payment mpp-session-* variants.
Step 1: Send the Original Request
Make the HTTP request the user asked for. If status is not 402, return the body directly — no payment, no wallet check, no other tool calls.
Step 2: Detect the Protocol
Priority 1: response.headers['WWW-Authenticate']
starts with "Payment " → MPP → protocols/mpp.md
Priority 2: response.headers['PAYMENT-REQUIRED']
base64-encoded JSON → x402 v2 → protocols/x402.md
Priority 3: response body JSON has "x402Version"
→ x402 v1 → protocols/x402.md
Otherwise → not a supported payment protocol, stop
Both headers present — STOP and ask:
The server offers both MPP and x402 payment protocols. Which would you like to use?
MPP (newer, supports sessions and streaming, recommended)
x402 (simpler, single-shot)
Step 3: Dispatch
Load the matching playbook and follow it from decode → confirm → wallet check → sign → assemble header → replay → suggest next steps: