outcome-mcp

An MCP server that lets an agent check it was actually paid.

npx outcome-mcp

No configuration. The defaults point at a live Sepolia deployment, and every read-only tool — including verifying any transaction — works without a credential. Only settlement moves money, and only settlement needs a key.

Install into a client

{
  "mcpServers": {
    "outcome": {
      "command": "npx",
      "args": ["-y", "outcome-mcp"]
    }
  }
}

.mcp.json for Claude Code, or claude_desktop_config.json for Claude Desktop.

Why

x402 releases funds when a facilitator returns success, and the buyer is expected to trust it. status: 0x1 only means the EVM did not revert — a transaction can mine, emit no logs, transfer nothing, and still be recorded as a payment.

Try it the moment the server is up:

outcome_verify
  transactionHash  0xf2c4055d08d9b52ca5f4f89fe2cd6c670e2204c2458e4731fd3c0ae0eda5073c
  recipient        0x000000000000000000000000000000000000dEaD
  minAmount        2000000

That transaction mined successfully on Sepolia and paid nobody.

Tools

| Tool | Does | |---|---| | outcome_intent_id | Derive the id for a piece of work. Two agents given the same task and payee get the same id, so a duplicate is refused on chain rather than paid for twice. | | outcome_get_intent | State, amount, and beneficiary — the address the work actually has to reach. | | outcome_verify | Did this transaction move value? Reads the receipt for a real ERC-20 Transfer. Read-only. | | outcome_settle | Release or refund, decided from a transaction hash. | | outcome_diagnose | Why an execution failed and whether resending helps. In-flight is never worth resending. | | outcome_audit | The decision record: what was verified, what was settled, and why. |

outcome_settle accepts a transaction hash and nothing else — no verdict, no done flag, no description of the work. An agent that could assert its way to a payout would be the thing this replaces. A test asserts the schema still has exactly two fields.

Configuration

| Variable | Meaning | Default | |---|---|---| | OUTCOME_RPC_URL | RPC endpoint | public Sepolia | | OUTCOME_ESCROW | OutcomeEscrow address | the live deployment | | OUTCOME_TOKEN | ERC-20 address | tUSDC on Sepolia | | OUTCOME_CHAIN_ID | chain id | 11155111 | | KEEPERHUB_API_KEY | enables outcome_settle | unset — read-only | | OUTCOME_AUDIT_LOG | decision trail path, or - to disable | .outcome/audit.jsonl |

Built on outcome-sdk. Source and console: github.com/nickthelegend/outcome.

MIT