Append Conversation Message

POST /openapi/memorylake/api/v3/conversations/{conversationId}/messages

Appends a new message to a conversation. Each message contains one or more content blocks (text, file, or both) and is attributed to an actor. MemoryLake automatically processes new messages to extract structured facts.

Permission required: project:conv_append

Path Parameters

string

required

Conversation identifier

Request Body

array

required

Array of content blocks that make up the message body. Each block must include a block_type field.Accepted block_type values: TEXT, FILE, IMAGE, THINKING, TOOL_USE, TOOL_RESULT.Text block: { "block_type": "TEXT", "text": "message content" }Image block: { "block_type": "IMAGE", "uri": "drive://...", "mime_type": "image/png" }

string

required

ID of the actor sending this message. Should reference an actor participating in the conversation.

string

ISO 8601 timestamp for when the message originally occurred. Use this when ingesting historical conversations so MemoryLake preserves the original timeline.

object

Arbitrary key-value metadata to attach to the message

string

required

Caller-defined unique identifier for the message within the conversation

string|null

required

ID of the message that comes immediately before this one in the conversation — its predecessor. This is an ordering pointer, not a reply pointer: pass the previous message’s ID even when the new message is not a reply to it. Order is declared by you, never guessed by the server.Send null for the first message of a conversation, which has no predecessor. Every message after that must carry a real ID — the id returned when you appended the previous message, or the conversation’s current_message_id when you resume an existing conversation.That ID must still be the conversation’s latest message when the request arrives. If it is not — a stale ID, or null on a conversation that already has messages — the append fails with 409 and nothing is written. Re-read current_message_id and retry with that value.

curl -X POST 'https://app.memorylake.ai/openapi/memorylake/api/v3/conversations/conv_7d2e3f4a5b6c7d8e/messages' \
  -H 'Authorization: Bearer sk_xxxxxx' \
  -H 'Content-Type: application/json' \
  -d '{
    "content": [
      {
        "block_type": "TEXT",
        "text": "Can you summarize last quarter'\''s revenue numbers?"
      }
    ],
    "custom_id": "msg-001",
    "actor_id": "actor_user_jane",
    "parent_message_id": null,
    "timestamp": "2025-06-01T14:10:00Z",
    "metadata": {
      "source": "web-app"
    }
  }'

curl -X POST 'https://app.memorylake.ai/openapi/memorylake/api/v3/conversations/conv_7d2e3f4a5b6c7d8e/messages' \
  -H 'Authorization: Bearer sk_xxxxxx' \
  -H 'Content-Type: application/json' \
  -d '{
    "content": [
      {
        "block_type": "TEXT",
        "text": "Here is the chart for your review."
      },
      {
        "block_type": "IMAGE",
        "uri": "drive://items/item_abc123/chart.png",
        "mime_type": "image/png"
      }
    ],
    "custom_id": "msg-002",
    "actor_id": "actor_assistant_v2",
    "parent_message_id": "msg_3f4a5b6c7d8e9f0a",
    "timestamp": "2025-06-01T14:10:30Z"
  }'

curl -X POST 'https://app.memorylake.ai/openapi/memorylake/api/v3/conversations/conv_7d2e3f4a5b6c7d8e/messages' \
  -H 'Authorization: Bearer sk_xxxxxx' \
  -H 'Content-Type: application/json' \
  -d '{
    "content": [
      {
        "block_type": "TEXT",
        "text": "Good point — I'\''ve updated the figures in the attached version."
      }
    ],
    "custom_id": "msg-003",
    "actor_id": "actor_user_jane",
    "parent_message_id": "msg_9e4b2c3d5f6a7b8c"
  }'

Response

object

Show Message object

string

Unique message identifier

array

Array of content blocks that make up the message body

Show Content block

string

Block type: TEXT, FILE, IMAGE, THINKING, TOOL_USE, TOOL_RESULT

string

Text content (present when block_type is TEXT)

string

Drive resource URI (present when block_type is IMAGE)

string

MIME type of the image (present when block_type is IMAGE)

object

Arbitrary key-value metadata attached to the message

string

Caller-provided timestamp for when the message originally occurred (ISO 8601)

string

ID of the conversation this message belongs to

integer

Position of this message within the conversation

string

ID of the actor who sent this message

string

Type of the actor: HUMAN or ASSISTANT

string

Creation timestamp

{
  "success": true,
  "data": {
    "id": "msg_3f4a5b6c7d8e9f0a",
    "content": [
      {
        "block_type": "TEXT",
        "text": "Can you summarize last quarter's revenue numbers?"
      }
    ],
    "metadata": {
      "source": "web-app"
    },
    "timestamp": "2025-06-01T14:10:00Z",
    "conversation_id": "conv_7d2e3f4a5b6c7d8e",
    "sequence_no": 1,
    "actor_id": "actor_user_jane",
    "created_at": "2025-06-01T14:10:05Z"
  }
}

MemoryLake API

Management API

Append Conversation Message

Path Parameters

Request Body

Response

​Path Parameters

​Request Body

​Response

Path Parameters

Request Body

Response