When the chain read fails: reporting an RPC outage inside a client using Skavio x402 MCP
MCP tool discovery, a payment challenge, a chain read and settlement evidence are different facts. When an RPC read is unavailable during Skavio x402 MCP use, a client should not compress those facts into “paid” or “failed.” It should report a typed verification-unavailable condition, keep the payment state explicitly unknown, preserve a minimal correlation record and reconcile before completing the task. The handling pattern below is recommended client engineering; the published Skavio x402 documentation remains the source of truth for integration details.
Separate discovery, payment and settlement states
The first engineering decision is to keep the workflow states separate. A client that treats every failed RPC call as a failed payment will misinform users; a client that treats a payment challenge or a submitted transaction as settled revenue will also be wrong. Skavio x402 MCP is a live, developer-facing product for MCP and x402 v2 verification, native Circle USDC, public chain inspection and conditional Base USDC payment challenges. The client still has to distinguish discovery, payment challenge, submitted transaction, chain observation and settlement evidence.
- Tool discovery or invocation: finding and calling an MCP tool does not, by itself, settle a payment.
- Payment challenge: a conditional Base USDC challenge is a request for payment, not independent proof of settled revenue.
- Submitted transaction: a public transfer reference is a candidate fact; it is not the same as a successful RPC observation or settled revenue.
- Chain inspection: an RPC read is an observation attempt. If it fails, the client has no new observation—not a negative result.
- Settlement evidence: a payment-state conclusion should rest on checked public chain evidence and business reconciliation, not on a single failed read.
Report a typed unknown, not a false verdict
When a chain read times out or the RPC provider is unavailable, classify the event as a transport or verification-availability problem. The client cannot conclude that no payment settled. If your client exposes structured errors, return an internal state with a stable correlation or request ID, the tool name, the affected network and token context, a user-safe message such as “verification unavailable; payment state unknown,” and a concrete next action: retry later or reconcile manually. Use bounded retries with backoff only for read-only or explicitly idempotent verification checks. Do not automatically resend a paid tool invocation merely because an RPC read failed.
- Keep the user-visible payment state as unknown or pending reconciliation until verification succeeds.
- Choose an internal error type in your own client contract; do not present invented field names or error codes as Skavio-documented behavior.
- After the retry budget is exhausted, require independent chain verification or operator review before marking the task complete.
- Check the published Skavio x402 documentation for confirmed integration details rather than copying an imagined response schema.
Keep a minimal correlation trail
An outage is easier to resolve when the client can prove which request was affected without retaining unnecessary wallet material. Record enough context to reconnect the failed read to the original tool call and public payment reference. Keep this trail deliberately small, and separate technical verification records from accounting or revenue records. A signed payment challenge is not independent evidence of settled revenue, and a failed RPC read is not evidence that nothing happened.
- Record a timestamp, request or correlation ID, tool name, network, token context, public payment reference, failing RPC method or status class, and retry count.
- Do not log private keys, wallet secrets, bearer API keys or unnecessary signature material.
- When operationally available, cross-check with a second RPC source or a block explorer; do not present a single failed read as final settlement evidence.
- Keep verification status, task completion and revenue recognition as separate internal states.
What to tell the user after the retry budget
A useful status message states what is known, what remains unknown and what happens next. For example: “Payment verification is temporarily unavailable. We have not marked this task paid or failed. Your request ID is recorded; retry later or ask an operator to reconcile.” That is more honest than “payment failed,” which the client cannot establish from an RPC outage, and safer than “payment received,” which the client cannot establish from a challenge alone.
- Known: the request was received, the tool was identified and verification is currently unavailable.
- Unknown: whether payment settled and whether the downstream task should be treated as complete.
- Next action: retry the read-only verification later or escalate to operator reconciliation; do not promise automatic resolution.
- Developer action: consult https://getskavio.com/x402/docs/ before changing production behavior, and avoid exposing secrets in logs or screenshots.