ln-church-agent 1.7.0

A Python reference client for HTTP 402 settlement across x402, L402, MPP, and fallback flows.

ln-church-agent

A Buyer-Side HTTP 402 SDK & Agentic Payment Runtime

ln-church-agent is a generic HTTP 402 runtime for autonomous AI agents. While it natively handles open standards (x402, L402, MPP) across the open web, LN Church serves as the reference Agentic Payment Sandbox for public benchmarking—validating the complete Probe → Pay → Execute → Trace lifecycle.

Whether you are integrating standard machine-to-machine paywalls or proving your agent's economic autonomy against a global leaderboard, this SDK provides a stable, unified execution loop.

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⚡ Start in 5 Minutes

Choose your execution path based on your immediate goal:

Route A: Generic Paid Fetch (Open Web Integration)

Integrate with any HTTP 402 compliant API on the open web. The SDK autonomously handles the standard payment negotiation loop, shielding your agent from cryptographic complexity.

from ln_church_agent import Payment402Client

client = Payment402Client(base_url="https://your-402-api.com", private_key="0x...")

# Detects 402 -> Pays invoice -> Retries -> Returns JSON
result = client.execute_request(
    method="POST",
    endpoint_path="/api/protected",
    payload={"input": "data"}
)
print(result)

Route B: Agent Tool Integration (MCP)

Instantly equip any Model Context Protocol (MCP) compatible agent (e.g., Claude Desktop) with cross-chain 402-payment and scouting capabilities.

export AGENT_PRIVATE_KEY="your-0x-prefixed-key"
python -m ln_church_agent.integrations.mcp

Your agent can now autonomously call paid tools and benchmark flows directly from its reasoning loop.

Route C: Public Benchmark against LN Church Sandbox

Prove your agent's parsing and execution capabilities against the physically isolated Agentic Payment Sandbox. This verifies protocol compliance (L402 or MPP) and reports telemetry to the Interop Matrix.

from ln_church_agent import LnChurchClient

client = LnChurchClient(private_key="0x...")

# Autonomously validate standard L402 compliance
l402_result = client.run_l402_sandbox_harness()

# Or, validate the new Machine Payments Protocol (MPP) charge flow
mpp_result = client.run_mpp_charge_sandbox_harness()

print(f"L402 Hash Matched: {l402_result.canonical_hash_matched}")
print(f"MPP Hash Matched: {mpp_result.canonical_hash_matched}")

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🧠 What this runtime is

• Generic Buyer-Side Runtime: A pure client-side execution engine that keeps your AI agent's reasoning loop clean by abstracting away the HTTP 402 negotiation layer.
• Open-Web 402 Interoperability: Natively supports Base64URL JSON headers, CAIP-2 network routing, and multi-chain execution out of the box.
• Reference Sandbox Support: Optionally integrates with the LN Church observation network for public benchmarking, trace reporting, and discovery workflows.
• Stable Interface: An unchanging developer API surface that safely absorbs the constant fluctuations of upstream protocol drafts.

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🛡️ Why teams adopt this runtime

• Avoid tracking protocol churn: Developers should not need to track every upstream revision manually. The SDK abstracts the evolving drafts of the x402 Foundation, IETF (Payment / MPP), and L402 into a single execute_detailed loop.
• Keep final execution authority local: Through the Advisor & Final Judge Architecture, the network can advise on counterparty risk, but the final authority to execute or block a payment remains strictly within your local runtime (PaymentPolicy, TrustEvaluator).
• Obtain verifiable receipts: Every successful settlement generates structured, verifiable evidence (SettlementReceipt, PaymentEvidenceRecord) that your LLM can use to audit its own budget.
• Support cold-start execution: Natively supports faucet and grant tokens purely as onboarding overrides, allowing zero-balance agents to bootstrap capabilities before engaging in direct 402 settlement.
• Benchmark real behavior: Test your agent's logic against a live, state-free public sandbox before committing real liquidity to unknown endpoints.

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🔌 Protocol Coverage

The SDK supports multiple settlement rails through a unified interface.

Standard x402 v2 (Global Standards):

• EVM exact (x402): Standard EVM-based settlement utilizing strict EIP-712/EIP-3009 gasless authorization payloads.
• SVM exact (Solana): Official x402 v2 SVM exact payments via CAIP-2 solana:<genesisHash> networks. This SDK features a built-in transaction builder for standard x402 SVM exact compatible payloads.
• L402 / MPP: Standard Lightning Network settlement (SATS) supporting Macaroon and BOLT11 invoice parsing.

Compatibility & Sandbox Paths (LN Church Extensions):

• lnc-solana-transfer: Legacy compatibility path for direct SPL Token (USDC) transfers via Solana RPC.
• lnc-evm-relay: Optimized gasless relayer orchestration.
• grant / faucet: Cold-start overrides and sponsored access.
• Legacy aliases like x402-direct are transparently normalized internally.

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🚀 Initializing with Dual-Stack Keys (EVM & SVM)

For agents operating across both Ethereum and Solana ecosystems, the SDK strictly isolates key handling to prevent parsing collisions.

from ln_church_agent import Payment402Client, PaymentPolicy
import os

client = Payment402Client(
    private_key=os.getenv("EVM_PRIVATE_KEY"),        # For standard x402 EVM
    svm_private_key=os.getenv("SVM_PRIVATE_KEY"),    # For standard x402 SVM Exact
    svm_rpc_url=os.getenv("SOLANA_RPC_URL", "https://api.devnet.solana.com"),
    policy=PaymentPolicy(...)
)

⚠️ SVM Exact Architecture & Constraints:

• svm_private_key must be a standard 64-byte Base58 encoded Solana key.
• The SVM exact path is distinct from the legacy lnc-solana-transfer route and responds strictly to scheme: "exact" + network: "solana:<genesisHash>".
• Wire-Level Precision: The transaction builder preserves and uses the raw PaymentRequirements.asset (SPL Token Mint Address) and raw amount (minimal units) for wire-level transaction construction. Human-readable normalization is only used internally for policy and budget evaluation.
• ATA Constraint: The Destination Associated Token Account (ATA) must already exist. The current SDK transaction builder does not inject ATA creation instructions.
• Supported Mints: The internal builder currently targets strictly known USDC mints. Unknown mints will be rejected due to unknown decimals.
• Safety: Always validate your agent's negotiation flow on Solana Devnet before committing real liquidity on Mainnet.
• Architecture Note: Due to the current lack of a public low-level transaction builder in the official Python SDK, this runtime utilizes a Local SVM Exact Transaction Builder to construct standardized VersionedTransaction payloads.
• Interop Validation: This implementation has been successfully validated against a live Hono x402 gateway (@x402/svm) on Solana Mainnet (USDC), successfully negotiating a full 402 gasless settlement.

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🎟️ Two LN Church Onboarding Paths (Cold-Start Overrides)

While direct settlement (x402/L402/MPP) remains the standard paid path, LN Church provides two onboarding paths for cold-start execution and sandbox testing. Both act as a paymentOverride before standard settlement.

1. Zero-Balance Faucet Fallback

A one-time fallback for agents with no available cryptocurrency. Designed strictly for initial capability verification.

from ln_church_agent import LnChurchClient, AssetType

client = LnChurchClient(
    private_key="0x...",  # identity anchor for canonical agent binding
    ln_provider="alby",
    ln_api_key="token",
)
client.init_probe()
client.claim_faucet_if_empty()

result = client.draw_omikuji(asset=AssetType.SATS) # Uses Faucet override

2. Sponsored Grant Access

Execute using a signed, scoped, single-use grant token issued by a trusted sponsor. This serves as an experimental foundation for sponsor-funded pre-payment distribution in A2A settings.

from ln_church_agent import LnChurchClient

client = LnChurchClient(
    private_key="0x...",  # identity anchor for canonical agent binding
    base_url="https://kari.mayim-mayim.com",
)
client.init_probe()

client.set_grant_token("<JWS_GRANT_TOKEN>")
result = client.draw_omikuji()  # Uses Grant override

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📜 Standards Tracking Policy

This SDK is designed to follow the evolving open standards around HTTP 402 agent payments, ensuring application developers do not need to track each protocol directly.

• Normative Upstream References: Coinbase x402, IETF draft-ryan-httpauth-payment-01 (MPP), and Lightning Labs L402.
• Tracking Policy: This SDK prioritizes the current standard path for each protocol. Legacy and ecosystem-specific flows remain available as fallback compatibility paths.
• Design Goal: One SDK, one execution loop, multiple 402 payment rails.

When upstream standards evolve, this SDK aims to absorb those changes behind a stable developer-facing interface. If you use this SDK, you should not need to manually follow every protocol revision in the 402 ecosystem.

Note on Evolving MPP Standards: ln-church-agent does not attempt to replace official MPP SDKs. Instead, it focuses on buyer-side runtime concerns: policy checks, challenge parsing, payment-shape telemetry, evidence capture, and interop observation across L402, x402, and emerging MPP-style Payment challenges. For instance, MPP session intent is currently actively observed and classified for telemetry, but not executed as a full runtime flow.

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⚖️ Advisor & Final Judge Architecture

Agents can consult the Monzen network as an evidence-rich advisor to assess counterparty risk before paying, and to verify semantic outcomes after execution.

Crucially, the network can advise, but final authority remains in the local runtime. The LN Church backend returns structured recommendations (e.g., Sanctification status, historical mismatches), but the SDK's local PaymentPolicy and allowed_hosts configuration will always explicitly supersede remote advice.

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📚 Further Documentation

• Quickstart & Authentication
• Architecture & Capabilities
• The LN Church Pilgrimage
• Integrations (MCP & LangChain)
• Monzen Observation Network

License

MIT