> ## Documentation Index > Fetch the complete documentation index at: https://docs.cxp.crescendo.ai/llms.txt > Use this file to discover all available pages before exploring further. # Add a conversation internal note > Append one text-only internal note to a non-closed Conversation with trusted API system attribution. Notes are never sent to the customer; existing internal notifications still apply. Repeated identical requests can create multiple notes. API-key identifiers are omitted from the result. Requires a tenant API key with cxm:conversations.write or an existing broader write scope. The complete JSON body must not exceed 32768 bytes. Each invocation executes independently, with no request deduplication, version precondition, preparation step, or retry protection. A timeout may follow a successful commit. Merged and non-customer records are rejected. ## OpenAPI ````yaml /api-reference/openapi-v1.json post /api/v1/cxm/tenants/{tenantId}/conversations/{conversationId}/internal-notes openapi: 3.1.0 info: title: Crescendo CXP API version: 1.0.0 description: >- Use the Customer Experience Platform API from trusted server-side applications to create Conversations, read projected detail and stored history, update operational fields, assign work, and add internal notes. Writes execute independently; repeating a write may repeat its effects. servers: - url: https://platform.crescendo.ai description: Production security: [] tags: - name: Conversations description: Create, continue, and manage customer conversations. paths: /api/v1/cxm/tenants/{tenantId}/conversations/{conversationId}/internal-notes: post: tags: - Conversations summary: Add a conversation internal note description: >- Append one text-only internal note to a non-closed Conversation with trusted API system attribution. Notes are never sent to the customer; existing internal notifications still apply. Repeated identical requests can create multiple notes. API-key identifiers are omitted from the result. Requires a tenant API key with cxm:conversations.write or an existing broader write scope. The complete JSON body must not exceed 32768 bytes. Each invocation executes independently, with no request deduplication, version precondition, preparation step, or retry protection. A timeout may follow a successful commit. Merged and non-customer records are rejected. operationId: addConversationInternalNote parameters: - name: tenantId in: path required: true description: Exact tenant-authorized ID without path separators. schema: type: string maxLength: 128 minLength: 1 example: tenant_demo - name: conversationId in: path required: true description: Exact tenant-authorized ID without path separators. schema: type: string maxLength: 512 minLength: 1 example: CX123 requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/AddConversationInternalNoteRequest' example: body: Customer requested a billing review. responses: '201': description: Committed operation result; notification delivery is not implied. content: application/json: schema: $ref: '#/components/schemas/ConversationInternalNoteResponse' '400': description: >- Invalid fields, unknown properties, or a disallowed status transition. content: application/json: schema: $ref: '#/components/schemas/Error' example: code: BadRequest message: >- Invalid fields, unknown properties, or a disallowed status transition. '401': description: The API key is missing, invalid, or expired. content: application/json: schema: $ref: '#/components/schemas/Error' example: code: Unauthenticated message: The API key is missing, invalid, or expired. '403': description: The API key does not authorize this tenant or operation. content: application/json: schema: $ref: '#/components/schemas/Error' example: code: PermissionDenied message: The API key does not authorize this tenant or operation. '404': description: >- The customer Conversation or active assignee is unavailable in this tenant. content: application/json: schema: $ref: '#/components/schemas/Error' example: code: NotFound message: >- The customer Conversation or active assignee is unavailable in this tenant. '409': description: >- The Conversation is merged/Closed, a lock is held, or lifecycle/realtime ownership constraints reject the operation. content: application/json: schema: $ref: '#/components/schemas/Error' example: code: Conflict message: >- The Conversation is merged/Closed, a lock is held, or lifecycle/realtime ownership constraints reject the operation. '413': description: The JSON body exceeds 32768 bytes. content: application/json: schema: $ref: '#/components/schemas/Error' example: code: PayloadTooLarge message: The JSON body exceeds 32768 bytes. '429': description: The request exceeds the API rate limit. content: application/json: schema: $ref: '#/components/schemas/Error' example: code: RateLimitExceeded message: The request exceeds the API rate limit. headers: Retry-After: description: Seconds to wait before another request. schema: type: integer minimum: 1 '502': description: The downstream request failed; the write may already have completed. content: application/json: schema: $ref: '#/components/schemas/Error' example: code: BadGateway message: >- The downstream request failed; the write may already have completed. '503': description: >- A required service is unavailable; the write may already have completed. content: application/json: schema: $ref: '#/components/schemas/Error' example: code: ServiceUnavailable message: >- A required service is unavailable; the write may already have completed. '504': description: The request timed out; the write may already have completed. content: application/json: schema: $ref: '#/components/schemas/Error' example: code: GatewayTimeout message: The request timed out; the write may already have completed. security: - BearerApiKey: [] components: schemas: AddConversationInternalNoteRequest: type: object additionalProperties: false properties: body: type: string maxLength: 20000 minLength: 1 description: >- Non-blank internal note text. The complete JSON body must also fit within 32768 bytes. required: - body ConversationInternalNoteResponse: type: object additionalProperties: false properties: note: type: object additionalProperties: false properties: id: type: string createdAt: type: string format: date-time visibility: type: string const: internal author: type: object additionalProperties: false properties: type: type: string enum: - agent - system id: type: - string - 'null' name: type: string maxLength: 256 required: - type - id - name required: - id - createdAt - visibility - author required: - note Error: type: object additionalProperties: false required: - code - message properties: code: type: string enum: - BadRequest - InvalidCustomField - Unauthenticated - PermissionDenied - EmailChannelNotFound - AssigneeNotFound - NotFound - EmailChannelDisabled - ContactIdentityConflict - OrganizationAmbiguous - AssigneeAmbiguous - Conflict - PayloadTooLarge - RateLimitExceeded - BadGateway - ServiceUnavailable - GatewayTimeout message: type: string securitySchemes: BearerApiKey: type: http scheme: bearer description: >- Tenant API key with `cxm:conversations.write`, `cxm:conversations.*`, `cxm:write`, or `cxm:*` scope. Keep it in a trusted backend; do not expose it in browser code. ````