Brickken

Brickken provides ERC-8004 identity, reputation, and agent-token operations on Base mainnet, with Base Sepolia available for tests. Prepare is free through exposed Brickken MCP tools, the hosted Brickken MCP HTTP API (https://mcp.brickken.com/mcp), or the Brickken CLI. Paid execution goes through Base MCP initiate_x402_request and complete_x402_request.

Brickken is initially the onchain operator in brickken-relayed mode. agentSetWallet changes the ERC-8004 operational wallet but does not transfer the ERC-721 identity. Transfer custody explicitly with agentTransferOwnership only when the user requests it.

Detection

Use this routing order:

1. If Brickken MCP tools are already exposed (prepare_transactions, get_transaction_status), call them directly.
2. Otherwise, if the harness has an HTTP tool and mcp.brickken.com is reachable via allowlist, call the hosted Brickken MCP API over HTTP.
3. With shell access, Brickken CLI is an alternative for prepare/status workflows.

Do not stop on shell-less surfaces when HTTP is available: the hosted Brickken MCP API is a valid fallback.

Regardless of the prepare surface, use Base MCP for x402 approval.

Installation

Optional Brickken MCP connector install (convenience path):

Brickken CLI for shell-capable harnesses:

Use the CLI in prepare/status mode only. Base MCP remains responsible for x402 approval and completion.

Endpoints

Hosted Brickken MCP endpoint:

• POST https://mcp.brickken.com/mcp
• Content-Type: application/json
• Accept: application/json, text/event-stream

JSON-RPC shape:

Response handling:

• Some harnesses return plain JSON-RPC result.
• Some stream SSE chunks; parse the final JSON object.
• MCP wrappers may place payload in result.content[0].text as a JSON string; parse and unwrap before mapping to txId, transactions, and x402Requirements.

Surface Routing

Commands

Use Brickken prepare_transactions through exposed MCP tools, hosted HTTP API (tools/call), or brickken tx prepare --method <method> --file <json> --json with executionMode: "brickken-relayed". Use chainId: "8453" for Base mainnet and chainId: "84532" for Base Sepolia tests. Omit signerAddress in relayed mode. For agentCreateToken, omit agentWallet.

agentRegister requires name, description, image, and a non-empty services array. image must be a publicly reachable HTTPS URL for the agent logo; do not use a local path or omit it. Ask for the user’s logo, or use an explicitly authorized test fixture.

Supported methods:

• Identity: agentRegister, agentSetURI, agentSetMetadata, agentSetWallet, agentTransferOwnership.
• Reputation: agentGiveFeedback, agentRevokeFeedback, agentAppendFeedbackResponse.
• Agent tokens: agentCreateToken, agentMintToken, agentBurnToken, agentTransferToken, agentTransferFromToken, agentApproveToken.

Prepare returns one txId, one unsigned transaction, and x402Requirements. If MCP or CLI wraps these fields under prepared, unwrap that object before submission.

For pending operations, use Brickken get_transaction_status through exposed MCP tools or hosted HTTP API, or:

Ownership transfer

Prepare agentTransferOwnership with agentUuid or agentId and newOwner. This creates an ERC-721 safeTransferFrom from Brickken custody to the requested wallet.

Ownership transfer is separate from agentSetWallet. After transfer, Brickken’s relayer can no longer perform owner-only operations unless ownership is returned.

Base Sepolia testing

• Use operation and payment network eip155:84532 (base-sepolia in Base MCP).
• The Brickken x402 test USDC is Circle USDC 0x036CbD53842c5426634e7929541eC2318f3dCF7e with 6 decimals, settled via EIP-3009 (EIP-712 name USDC, version 2, authorization window 300s).
• Always fund and pay with the exact asset quoted in x402Requirements; do not substitute another token.
• Expected ERC-8004 test registries are identity 0x8004A818BFB912233c491871b3d84c89A494BD9e and reputation 0x8004B663056A597Dffe9eCcC1965A193B7388713.
• Before initiating x402, verify the payer holds the asset returned by x402Requirements. Testnet balances may not appear in portfolio indexing; use a Base Sepolia balanceOf RPC read when necessary.
• If prepare reports that the registry is not configured, stop. No valid txId exists and no payment should be initiated.

Orchestration

1. Confirm the target (base or base-sepolia), the irreversible action, custody, and any public or PII fields.
2. Prepare through exposed Brickken MCP tools, hosted HTTP API, or CLI with chainId: "8453" for mainnet or "84532" for tests and executionMode: "brickken-relayed".
3. Require a scalar txId and exactly one transaction. Preserve to, data, and value exactly.
4. Validate that the quote network matches the operation network and that the payer holds the exact quoted asset. On Base Sepolia require Circle USDC 0x036CbD53842c5426634e7929541eC2318f3dCF7e. Parse the exact decimal from extra.displayPrice as maxPayment.
5. Call Base MCP initiate_x402_request with method POST, the active Brickken environment’s /send-transactions resource, the prepared body, and maxPayment. Do not switch environments between prepare and send.
6. Show the approval URL. Poll Base MCP get_request_status only after the user acts, then call complete_x402_request(requestId).
7. Report confirmed only when Brickken returns status: "confirmed" and a transaction hash.
8. On status: "pending", use Brickken get_transaction_status through exposed MCP tools or hosted HTTP API, or brickken tx status. Do not resubmit or pay the same txId again. Brickken’s reconciliation settles after confirmation or releases on revert/authorization expiry.
9. To transfer an identity to the Base Account, call Base MCP get_wallets, prepare agentTransferOwnership with that address as newOwner, and run a separate x402 approval.

Submission

Use Base MCP initiate_x402_request, get_request_status, and complete_x402_request. Exposed Brickken MCP tools, hosted HTTP API, or CLI produce the prepare result; Base MCP authorizes the quoted payment and completes the paid send resource.

Request body:

Mapping:

The Base Account is the x402 payer, while Brickken’s relayer is the onchain sender.

Example Prompts

“Register my agent on Base.” Prepare agentRegister through exposed Brickken MCP tools, hosted HTTP API, or CLI, disclose Brickken custody, complete the Base MCP x402 approval, and return agentUuid, txId, and the operation hash.

“Set my Base wallet as the agent wallet.” Use agentSetWallet with the required wallet authorization signature. Explain that this changes the operational wallet only.

“Send the agent NFT to my Base wallet.” Call Base MCP get_wallets, explicitly confirm loss of Brickken custody, then prepare and execute agentTransferOwnership with the Base Account as newOwner.

Risks & Warnings

• Custody. Brickken initially owns the ERC-721 identity and controls agent tokens created by its relayer.
• Ownership transfer. agentTransferOwnership is irreversible and disables later Brickken owner-only relayed actions for that identity.
• PII. Agent profiles and feedback may publish free text or contact data to IPFS/onchain storage.
• Payment. Prepare is free. Send charges the exact quoted USDC amount through Base MCP x402 approval.
• Retries. Never replay a txId after an operation hash exists. Poll status instead.

Notes

This workflow targets Base mainnet and Base Sepolia tests. A timeout leaves both operation and payment pending; Brickken’s background reconciliation settles only after a successful receipt and releases the authorization on revert or expiry.