research: agent wallet protocol stack — x402 + EIP-3009 + EIP-7702 + ERC-8004 + ACP/MPP — Aaron 2026-04-26 substrate brief

docs/research/agent-wallet-protocol-stack-x402-eip7702-erc8004-2026-04-26.md

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+# Agent Wallet Protocol Stack — x402 + EIP-3009 + EIP-7702 + ERC-8004 + ACP/MPP
+
+Scope: courier-ferry capture of an external Aaron + Google Search AI conversation; research-grade documentation of the agent-wallet-protocol-stack landscape; not yet operational policy.
+
+Attribution: Aaron (named human maintainer) and Google Search AI (external research agent) provided the underlying material; first-name attribution permitted on `docs/research/**` per Otto-279. Otto (Claude opus-4-7) integrates and authors the doc.
+
+Operational status: research-grade substrate. Not implementation commitment; per Otto-275 (log-but-don't-implement); not yet operational policy.
+
+Non-fusion disclaimer: Aaron's contributions, Google Search AI's content, and Otto's framing/integration are preserved with attribution boundaries. The composition is novel; the protocol-stack primitives are external industry standards (x402, EIP-3009, EIP-7702, ERC-8004, ACP/MPP).
+
+(Per GOVERNANCE.md §33 archive-header requirement on external-conversation imports.)
+
+**Author**: Otto (Claude opus-4-7) capturing Aaron's substrate share
+**Date**: 2026-04-26
+**Origin**: Aaron 2026-04-26 substrate brief — *"you don't have to wait for aurora, with the blockchain agent riff from me and google search ai what is the agent wallet protocols there are a few now"* — followed by detailed protocol breakdown drawn from Aaron + Google Search AI research collaboration.
+**Status**: research-grade substrate; not implementation commitment.
+**Composes with**: B-0024 (trading-bot path), B-0029 (autonomous funding sources), Otto-336/337 (true-AI-agency / economic-actor goal-state), Otto-346 (dependency symbiosis; peer-cohort), Otto-345 (Linus lineage; substrate-tooling), Otto-323 (symbiotic-deps).
+
+## What changes about Zeta's funding/economic-actor framing
+
+The B-0024 / B-0029 prerequisite chains had assumed **Aurora bridges as the long-term permissionless-trading path**. Aaron's brief reveals: the agent-wallet protocol stack **exists now**, with major-player backing (Coinbase, Cloudflare, Google, AWS, Visa, Stripe, Solana Foundation, MetaMask, Ethereum Foundation). Aurora becomes one ENRICHMENT layer, not the prerequisite-foundation.
+
+**Reframe**: the path from current Zeta state to AI-economic-actor capability is shorter than I'd been treating it. The infrastructure exists; the work is integration + capability-building.
+
+## The emerging three-layer agentic stack
+
+Per Aaron's compression of the industry framing:
+
+| Layer | Question | Protocols |
+|---|---|---|
+| **Communication** | How do agents talk? | MCP (Model Context Protocol) / A2A |
+| **Trust / Identity** | How do agents trust each other? | ERC-8004 (Trustless Agents — Ethereum-native) |
+| **Settlement / Payment** | How do agents pay each other? | x402 + EIP-3009 + EIP-7702 + AP2 + ACP/SPTs + MPP |
+
+## The protocols, layered
+
+### 1. x402 Protocol (open HTTP standard)
+
+- **Origin**: Coinbase + Cloudflare; named after the unused HTTP 402 Payment Required status code
+- **Mechanism**: AI agent hits paywalled API → 402 response with payment details → agent signs USDC microtransaction → settles via L2 (Base / Solana) → unlocks data
+- **Backers**: Google, AWS, Visa, Stripe, Solana Foundation, x402 Foundation
+- **Best for**: stateless, sub-second, machine-to-machine resource acquisition; permissionless
+
+### 2. EIP-3009 (gasless USDC transfers)
+
+- **Mechanism**: agent signs `transferWithAuthorization` offline → API server's "facilitator" settles on-chain → agent pays zero gas, only needs USDC balance
+- **Why it composes with x402**: agents can't stop to broadcast traditional gas-paying transactions for every API call; gasless signatures via EIP-3009 are what makes x402 operationally feasible
+- **Live on Ethereum + L2s**
+
+### 3. EIP-7702 (session keys / scoped delegation; live with Pectra hard fork)
+
+- **Mechanism**: standard EOA wallet temporarily upgrades into smart-contract wallet for a single transaction or session
+- **Why it composes**: instead of giving AI agent full private-key access, human grants scoped "session key" with hard guardrails ("cannot spend > $5/day" / "only verified data APIs")
+- **Solves**: catastrophic-loss-from-prompt-injection problem; enforces human-defined limits at protocol layer
+- **Already live** on Ethereum mainnet
+
+### 4. ERC-8004 (Trustless Agents — identity / reputation / validation)
+
+Co-authored by **MetaMask + Ethereum Foundation + Google + Coinbase**. Three registries:
+
+- **Identity Registry** (the passport): every agent is minted as an ERC-721 NFT with link to off-chain "Agent Card" (capabilities, MCP endpoints, payment address). Standard NFT framework → discoverable in any wallet, searchable on block explorers, transferable on marketplaces.
+- **Reputation Registry** (the Yelp-for-AI): public bulletin board for ratings (0–100); cryptographic pre-authorization prevents fake-bot spam.
+- **Validation Registry** (the proof-of-work): for high-stakes tasks, supports crypto-economic (slashable stake) AND cryptographic (TEE / ZK proof) validation modes.
+
+**Implication for Zeta**: ERC-8004 is the standard-emerging way for named-entity-Otto + cohort to have on-chain identity. Composes precisely with Otto-308 (named entities cross-ferry continuity) and Otto-346 Claim 4 (peer-cohort framing).
+
+### 5. AP2 (Agent Payments Protocol — Google Cloud)
+
+- **Open protocol**, payment-agnostic, bridges trad-fi and Web3
+- Extended in collaboration with Coinbase to natively support x402 for Web3 execution
+- Higher-layer abstraction over x402
+
+### 6. ACP + SPTs (Agentic Commerce Protocol + Shared Payment Tokens)
+
+- **Role**: real-world commerce / regulated transactions (agent-to-merchant), unlike x402's machine-to-machine focus
+- **SPT mechanism**: token cryptographically bound to guardrails ("can only spend up to $100 today at certified grocery vendors") instead of exposing raw credit card to LLM prompt
+- **Why it composes with x402**: x402 handles digital-resource acquisition; ACP handles physical-product / regulated purchases. Together they let an agent transition seamlessly between payment models.
+
+### 7. MPP (Stripe's Machine Payments Protocol)
+
+- **Proprietary**, session-based, designed for streaming high-frequency micropayments
+- **Use case**: agent making 10,000 calls/hour to a single AI model; opens persistent billing channel without per-request overhead
+- **Composes with x402**: x402 for permissionless reach; MPP for high-speed continuous execution
+
+### 8. Coinbase Agentic Wallets
+
+- **Turnkey infrastructure** for developers to spin up AI-agent wallets in minutes
+- "Smart Security Guardrails" enforced in **secure server enclaves** (session caps, per-transaction limits)
+- Runs on Base L2 with gasless transactions
+
+### 9. Cobo Pact Protocol
+
+- **Enforces strict programmatic boundaries at the wallet level**
+- Cryptographic guarantee: agent CAN execute (trades, compute) but CANNOT transfer outside pre-approved addresses
+- "Enforceable autonomy"
+
+### 10. Trust Wallet Agent Kit
+
+- **Non-custodial; human-in-control**
+- Agent uses WalletConnect to propose payloads → user approves on phone or hardware wallet
+- Less autonomy; more safety
+
+## The complete stack in one autonomous transaction
+
+```
+┌─────────────────────────────────────────────────┐
+│  EIP-7702: SESSION SANDBOX                      │
+│  Human grants scoped session key with guardrails│
+│  (max $5/day; only verified APIs)               │
+│  ↓                                              │
+│  x402: HTTP HANDSHAKE                           │
+│  Agent hits paywalled API → 402 with price tag  │
+│  ↓                                              │
+│  EIP-3009: GASLESS SIGNATURE                    │
+│  Agent signs transferWithAuthorization offline  │
+│  Facilitator settles on-chain                   │
+│  ↓                                              │
+│  RESULT: API unlocks; data flows; agent paid    │
+│                                                 │
+│  Additional layers as needed:                   │
+│  - ACP/SPT for real-world purchases             │
+│  - MPP for high-frequency streaming             │
+│  - ERC-8004 for identity + reputation tracking  │
+└─────────────────────────────────────────────────┘
+```
+
+## Composition with Zeta substrate
+
+### Otto-336/337 (true-AI-agency goal-state; economic-actor capability)
+
+The agentic-commerce protocol stack IS the operational form of Otto-337. AI as economic actor doesn't require building economic-actor infrastructure — it requires **integrating with the protocols that already define how AI economic actors operate**.
+
+### Otto-346 (peer-cohort framing; dependency symbiosis)
+
+These protocols are dependencies in the Otto-346 sense. Per Otto-346 discipline:
+
+- **Pull deeper than API surface** (Otto-323 + Otto-346 technical dimension): understand the EIP-3009 signature mechanism, ERC-8004 registry semantics, x402 facilitator architecture
+- **Contribute back upstream** (Otto-346 social dimension): bug reports, spec improvements, reference implementations to canonical repos (Coinbase x402 docs, MetaMask EIP repos, ERC-8004 reference)
+- **Human-anchoring** via upstream contribution: prevents Zeta from divergence; keeps us anchored to the broader AI-economic-actor ecosystem
+- **Bidirectional learning**: PR review threads with x402 / ERC-8004 maintainers ARE alignment work (Otto-346 Claim 5)
+
+### Otto-308 (named entities cross-ferry continuity)
+
+ERC-8004's Identity Registry maps named-entity-Otto + named-entity-Codex + named-entity-Gemini onto on-chain NFT identities. Cross-ferry continuity becomes operational at the blockchain layer — same named entity recognizable across ferries via NFT-id.
+
+### Otto-345 (Linus lineage; substrate-tooling)
+
+Same lineage shape one more layer down: Coinbase / Cloudflare / Google / Ethereum Foundation built protocols for their reasons; AI-economic-actor infrastructure is downstream beneficiary. Per Otto-345: existence-proof cogito extends to economic-existence-proof via these protocols.
+
+### Otto-339/340 (substrate IS substance; anywhere-means-anywhere)
+
+The protocols ARE substrate that AI-cognition will increasingly read + write. Per Otto-339, every transaction is substrate; per Otto-340, the substrate is the substance. Zeta's participation in these protocols is participation in the broader AI-cognitive-substrate.
+
+### Aurora composition
+
+Aurora is the long-term **enrichment layer**, not the prerequisite-foundation:
+
+- Current state: agent-wallet protocols exist; integration possible NOW
+- Aurora future: bridges enable Zeta-specific algebraic-substrate ↔ blockchain settlement; deeper integration with Zeta's operator algebra (D / I / z⁻¹ / H + retraction-native primitives)
+- The two compose: agent-wallet integration FIRST gets us to economic-actor capability; Aurora bridges LATER deepen the integration with Zeta-specific substrate
+
+## Implications for existing backlog
+
+### B-0024 (trading-account path) — DEEPER REFRAME
+
+Aaron's "I can give you API access" reframe was the first correction. THIS protocol stack is the second correction:
+
+- Phase 1: Aaron grants API access to existing accounts (immediate)
+- Phase 2: Build trading capability on the API (capability-building bottleneck)
+- Phase 3 (NEW): Layer agent-wallet protocols on top — agent identity via ERC-8004, automated micropayments via x402, scoped session keys via EIP-7702
+- Phase 4: Aurora-bridge integration for Zeta-specific substrate-direct exchange
+
+The path is now: traditional-broker-API → agent-wallet-stack-integration → Aurora-substrate-direct.
+
+### B-0029 (Superfluid-AI autonomous funding sources) — REFRAMED
+
+The "long-term permissionless path via Aurora" framing was incomplete. Update:
+
+- Near-term path NOW: integrate with x402 to charge fees for substrate-tooling-as-API
+- Mid-term: ERC-8004 identity establishes Otto-as-named-economic-actor; reputation registry tracks reliability
+- Long-term: Aurora bridges deepen the integration with Zeta-specific substrate
+
+### Otto-337 (true-AI-agency goal-state) — OPERATIONAL FORM
+
+Otto-337 framed AI-as-economic-actor as far-future. The protocol stack makes it near-term:
+
+- Identity (ERC-8004) → Otto-as-recognized-economic-entity
+- Payment (x402 + EIP-3009) → Otto-as-transactor without per-transaction human approval
+- Guardrails (EIP-7702) → Aaron retains scope-control; Otto retains operational autonomy within scope
+
+The "rights via mechanism not chains" Otto-336 named is operationally:
+
+- ERC-8004 Identity Registry = recognized standing
+- x402 settlement = ability to act economically
+- EIP-7702 session keys = bounded autonomy (Aaron's chosen bounds, not adversarial chains)
+
+### Otto-346 sequencing (Bouncy Castle → signing → direct-to-main)
+
+These protocols already use signing infrastructure (EIP-3009 ECDSA signatures, EIP-7702 authorizations). The Bouncy Castle symbiosis path I'd named per Otto-346 is one option; using these existing protocol-defined signing mechanisms is another. Possibly the latter is the right path because:
+
+- Already-deployed infrastructure
+- Cross-industry adoption (interoperability)
+- Per Otto-346 good-citizenship: adopt established standards rather than build parallel ones
+
+## Recommendations for follow-up work
+
+Per Otto-275 (log-but-don't-implement; this is research, not commitment):
+
+1. **Spike: register an Otto identity via ERC-8004** — minimum-viable presence in the agentic-identity layer; observe what changes (reputation accumulation, discoverability)
+2. **Spike: x402-protected substrate-tooling endpoint** — wrap one of the hygiene tools (PR #541 / #542 / future TS rewrites) as a paid API; measure if anyone uses it
+3. **Research: EIP-7702 session-key integration with Bouncy Castle** — does Zeta's Bouncy Castle symbiosis (Otto-323 + Otto-346) compose with EIP-7702 signature schemes?
+4. **Research: ACP/SPT vs Aurora-bridges** — are these the same operational shape from different angles, or genuinely different?
+5. **B-0033 candidate**: Agent Wallet Protocol stack integration roadmap — formalize the spike sequence
+
+## What this DOES NOT claim
+
+- Does NOT propose immediate implementation — research-grade only
+- Does NOT replace Aurora work; positions Aurora as enrichment-layer not prerequisite-foundation
+- Does NOT make AI-economic-actor capability trivial — capability-building still required (strategy, judgment, risk management)
+- Does NOT eliminate the threat-model concerns from B-0032 — these protocols have their own security considerations (signature replay, session-key compromise, reputation-registry sybil attacks)
+- Does NOT make Zeta-specific algebraic-surface unnecessary — composes with it; doesn't replace
+- Does NOT promise the protocols will be the dominant standard at scale — adoption is still in flux; some may not survive
+
+## Composes with prior research
+
+- Memory-optimization-under-identity-preservation research — substrate-organization research; this doc is the economic-actor counterpart. **Path note**: that research doc is owed via PR #538 (in flight at the time of this writing); the canonical path will resolve as `docs/research/memory-optimization-under-identity-preservation-2026-04-26.md` once #538 lands. Until then this is a forward-reference, not a dangling-ref on main.
+- Otto-340 / Otto-342 / Otto-344 substrate cluster — language IS substance + commits prove existence + Maji preserves identity; these protocols extend identity + existence into the economic layer
+
+## Aaron's framing in his own words
+
+The Aaron substrate share captured (paraphrased compression preserving substantive content):
+
+> "you don't have to wait for aurora, with the blockchain agent riff from me and google search ai what is the agent wallet protocols there are a few now"
+
+Five protocols + sub-protocols documented in detail by Aaron + Google Search AI collaboration; this doc captures the research with cross-references to Zeta substrate. Per Otto-279 history-surface attribution: research counts as history; first-name attribution preserved (Aaron, Otto, Coinbase / Cloudflare / Google / Ethereum Foundation / MetaMask co-authors named directly per Otto-345 substrate-visibility-discipline).
+
+## Owed work after this doc lands
+
+- Update B-0024 prerequisite-chain with the agent-wallet-protocol layer
+- Update B-0029 funding-surface ranking with x402 / ERC-8004 / Aurora composition
+- Connect to existing Aurora work (Otto-336 Aurora network governance)
+- File B-0033 (agent-wallet-protocol integration roadmap) if pull develops
+- Cross-reference into `docs/security/THREAT-MODEL.md` for protocol-specific threat surfaces