> ## Documentation Index > Fetch the complete documentation index at: https://cobo.com/products/agentic-wallet/manual/llms.txt > Use this file to discover all available pages before exploring further. # Sign a message > This operation signs a message using the specified wallet via the Cobo WaaS platform. Currently supports EIP-712 structured data signing, with future support planned for raw hash signing, BTC signatures, and other schemes. Set `destination_type` to select the signing method: - `eip712` (default): EIP-712 typed structured data signing. Requires an EVM-compatible chain and the `eip712_typed_data` payload field. Set `sync=true` (default) to wait synchronously for the signing result before responding. Set `sync=false` to return immediately after submission; poll the transaction record to retrieve the signature later. Supply `request_id` to enable idempotency. If a message-sign transaction with the same `request_id` already exists for the same principal, the existing record is returned with `idempotent=true`. The operation returns an error if a policy denies the signing request. ## OpenAPI ````yaml post /api/v1/wallets/{wallet_uuid}/message-sign openapi: 3.1.0 info: title: Cobo Agentic Wallet Service description: Unified wallet engine for human and agent principals version: 1.3.0 servers: [] security: [] paths: /api/v1/wallets/{wallet_uuid}/message-sign: post: tags: - Transactions summary: Sign a message description: >- This operation signs a message using the specified wallet via the Cobo WaaS platform. Currently supports EIP-712 structured data signing, with future support planned for raw hash signing, BTC signatures, and other schemes. Set `destination_type` to select the signing method: - `eip712` (default): EIP-712 typed structured data signing. Requires an EVM-compatible chain and the `eip712_typed_data` payload field. Set `sync=true` (default) to wait synchronously for the signing result before responding. Set `sync=false` to return immediately after submission; poll the transaction record to retrieve the signature later. Supply `request_id` to enable idempotency. If a message-sign transaction with the same `request_id` already exists for the same principal, the existing record is returned with `idempotent=true`. The operation returns an error if a policy denies the signing request. operationId: message_sign parameters: - name: wallet_uuid in: path required: true schema: type: string format: uuid description: >- The UUID of the wallet that will sign the message. Retrieve this value from the `id` field returned when the wallet was created. title: Wallet Uuid description: >- The UUID of the wallet that will sign the message. Retrieve this value from the `id` field returned when the wallet was created. - name: X-API-Key in: header required: false schema: title: X-Api-Key type: string nullable: true requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/MessageSignCreate' responses: '200': description: Successful Response content: application/json: schema: $ref: '#/components/schemas/StandardResponse_MessageSignResult_' '422': description: Validation Error content: application/json: schema: $ref: '#/components/schemas/WrappedValidationError' components: schemas: MessageSignCreate: properties: chain_id: type: string title: Chain Id description: CAW/WaaS chain ID, e.g. 'ETH', 'SETH' destination_type: $ref: '#/components/schemas/MessageSignDestType' description: Signing type. Determines which payload field is used. default: eip712 eip712_typed_data: title: Eip712 Typed Data description: >- Complete EIP-712 typed data: {domain, types, primaryType, message}. Required when destination_type='eip712'. additionalProperties: true type: object nullable: true source_address: title: Source Address description: >- Specific address to sign with. If omitted, the wallet's most recently created address for this chain is used. type: string nullable: true description: title: Description type: string maxLength: 512 nullable: true sync: type: boolean title: Sync description: >- True: wait for signature before responding. False: return immediately after submit. default: true request_id: title: Request Id description: Idempotency key. Replays are scoped to the same principal. type: string maxLength: 255 nullable: true type: object required: - chain_id title: MessageSignCreate description: >- Request payload for message signing. Currently supports EIP-712 structured data signing. The ``destination_type`` field determines which payload field is required. StandardResponse_MessageSignResult_: properties: success: type: boolean title: Success default: true result: $ref: '#/components/schemas/MessageSignResult' suggestion: type: string title: Suggestion default: '' message: type: string title: Message default: '' meta: $ref: '#/components/schemas/PaginationMeta' nullable: true type: object required: - result title: StandardResponse[MessageSignResult] WrappedValidationError: title: WrappedValidationError type: object required: - success - error properties: success: type: boolean const: false default: false title: Success error: type: object title: Error required: - detail properties: detail: type: array title: Detail items: $ref: '#/components/schemas/ValidationError' MessageSignDestType: type: string enum: - eip712 title: MessageSignDestType description: Supported message signing destination types. MessageSignResult: properties: id: title: Id description: >- User transaction UUID assigned at submission time. Null if creation failed before assignment. type: string format: uuid nullable: true idempotent: type: boolean title: Idempotent description: >- Whether this response was returned from a previously submitted request with the same `request_id`. `true`: idempotent replay. `false`: new submission. default: false request_id: title: Request Id description: Client-supplied request identifier used for idempotency. type: string nullable: true status: type: integer title: Status description: >- The user transaction status code. Typical values: 100 (pending approval), 900 (success), 901 (failed), 902 (rejected). status_display: type: string title: Status Display description: >- The human-readable user transaction status (for example, `Initiated`, `Processing`, `Success`, `Failed`). default: '' approval_id: title: Approval Id description: >- The Approval V2 record ID when `status=pending_approval`. Use this to track the approval via the Approvals operations. type: string format: uuid nullable: true destination_type: $ref: '#/components/schemas/MessageSignDestType' description: 'Signing type used for this request. Possible values: `eip712`.' nullable: true signature: title: Signature description: Hex-encoded signature (e.g. 0x...). Null if not yet completed. type: string nullable: true type: object required: - status title: MessageSignResult description: Response for message signing. PaginationMeta: properties: total: title: Total type: integer nullable: true offset: title: Offset type: integer nullable: true limit: title: Limit type: integer nullable: true has_more: title: Has More type: boolean nullable: true after: title: After type: string nullable: true before: title: Before type: string nullable: true type: object title: PaginationMeta description: |- Pagination metadata for list responses. Supports both legacy offset-based and cursor-based pagination. Cursor fields (``has_more``, ``after``, ``before``) are populated for cursor-paginated endpoints. Legacy fields (``offset``, ``limit``) are populated when the caller uses the deprecated ``offset`` parameter. ValidationError: properties: loc: items: anyOf: - type: string - type: integer type: array title: Location msg: type: string title: Message type: type: string title: Error Type input: title: Input ctx: type: object title: Context type: object required: - loc - msg - type title: ValidationError ````