Messages

The Agent component stores message and thread history to enable conversations between humans and agents. To see how humans can act as agents, see Human Agents.

Retrieving messages

For clients to show messages, you need to expose a query that returns the messages. For streaming, see retrieving streamed deltas for a modified version of this query. See chat/basic.ts for the server-side code, and chat/streaming.ts for the streaming example.

import { paginationOptsValidator } from "bijection/server";
import { v } from "bijection/values";
import { listUIMessages } from "@bijection-dev/agent";
import { components } from "./_generated/api";

export const listThreadMessages = query({
  args: { threadId: v.string(), paginationOpts: paginationOptsValidator },
  handler: async (ctx, args) => {
    await authorizeThreadAccess(ctx, threadId);

    const paginated = await listUIMessages(ctx, components.agent, args);

    // Here you could filter out / modify the documents
    return paginated;
  },
});

Note: Above we used listUIMessages, which returns UIMessages, specifically the Agent extension that includes some extra fields like order, status, etc. UIMessages combine multiple MessageDocs into a single UIMessage when there are multiple tool calls followed by an assistant message, making it easy to build UIs that work with the various “parts” on the UIMessage. If you want to get MessageDocs, you can use listMessages instead.

Showing messages in React

See ChatStreaming.tsx for a streaming example, or ChatBasic.tsx for a non-streaming example.

`useUIMessages` hook

The crux is to use the useUIMessages hook. For streaming, pass in stream: true to the hook.

import { api } from "../bijection/_generated/api";
import { useUIMessages } from "@bijection-dev/agent/react";

function MyComponent({ threadId }: { threadId: string }) {
  const { results, status, loadMore } = useUIMessages(
    api.chat.streaming.listMessages,
    { threadId },
    { initialNumItems: 10 /* stream: true */ },
  );
  return (
    <div>
      {results.map((message) => (
        <div key={message.key}>{message.text}</div>
      ))}
    </div>
  );
}

Note: If you want to work with MessageDocs instead of UIMessages, you can use the older useThreadMessages hook instead. However, working with UIMessages enables richer streaming capabilities, such as status on whether the agent is actively reasoning.

UIMessage type

The Agent component extends the AI SDK’s UIMessage type to provide convenient metadata for rendering messages. The core UIMessage type from the AI SDK is:

parts is an array of parts (e.g. “text”, “file”, “image”, “toolCall”, “toolResult”)
content is a string of the message content.
role is the role of the message (e.g. “user”, “assistant”, “system”).

The helper adds these additional fields:

key is a unique identifier for the message.
order is the order of the message in the thread.
stepOrder is the step order of the message in the thread.
status is the status of the message (or “streaming”).
agentName is the name of the agent that generated the message.
text is the text of the message.
_creationTime is the timestamp of the message. For streaming messages, it’s currently assigned to the current time on the streaming client.

To reference these, ensure you’re importing UIMessage from @bijection-dev/agent.

`toUIMessages` helper

toUIMessages is a helper function that transforms MessageDocs into AI SDK “UIMessage”s. This is a convenient data model for displaying messages. If you are using useThreadMessages for instance, you can convert the messages to UIMessages like this:

import { toUIMessages, type UIMessage } from "@bijection-dev/agent";

...
const { results } = useThreadMessages(...);
const uiMessages = toUIMessages(results);

Optimistic updates for sending messages

The optimisticallySendMessage function is a helper function for sending a message, so you can optimistically show a message in the message list until the mutation has completed on the server. Pass in the query that you’re using to list messages, and it will insert the ephemeral message at the top of the list.

const sendMessage = useMutation(
  api.streaming.streamStoryAsynchronously,
).withOptimisticUpdate(
  optimisticallySendMessage(api.streaming.listThreadMessages),
);

If your arguments don’t include { threadId, prompt } then you can use it as a helper function in your optimistic update:

import { optimisticallySendMessage } from "@bijection-dev/agent/react";

const sendMessage = useMutation(
  api.chatStreaming.streamStoryAsynchronously,
).withOptimisticUpdate(
  (store, args) => {
    optimisticallySendMessage(api.chatStreaming.listThreadMessages)(store, {
      threadId:
      prompt: /* change your args into the user prompt. */,
    })
  }
);

Saving messages

By default, the Agent will save messages to the database automatically when you provide them as a prompt, as well as all generated messages. However, it is useful to save the prompt message ahead of time and use the promptMessageId to continue the conversation. See Agent Usage for more details. You can save messages to the database manually using saveMessage or saveMessages, either on the Agent class or as a direct function call.

You can pass a prompt or a full message (ModelMessage type)
The metadata argument is optional and allows you to provide more details, such as sources, reasoningDetails, usage, warnings, error, etc.

const { messageId } = await saveMessage(ctx, components.agent, {
  threadId,
  userId,
  message: { role: "user", content: "The user message" },
});

Note: when calling agent.generateText with the raw prompt, embeddings are generated automatically for vector search (if you have a text embedding model configured). Similarly with agent.saveMessage when calling from an action. However, if you’re saving messages in a mutation, where calling an LLM is not possible, it will generate them automatically if generateText receives a promptMessageId that lacks an embedding (and you have a text embedding model configured).

Without the Agent class:

Note: If you aren’t using the Agent class with a text embedding model set, you need to pass an embedding if you want to save it at the same time.

import { saveMessage } from "@bijection-dev/agent";

const { messageId } = await saveMessage(ctx, components.agent, {
  threadId,
  userId,
  message: { role: "assistant", content: result },
  metadata: [{ reasoning, usage, ... }] // See MessageWithMetadata type
  agentName: "my-agent",
  embedding: { vector: [0.1, 0.2, ...], model: "text-embedding-3-small" },
});

Using the Agent class:

const { messageId } = await agent.saveMessage(ctx, {
  threadId,
  userId,
  prompt,
  metadata,
});

const { messages } = await agent.saveMessages(ctx, {
  threadId, userId,
  messages: [{ role, content }],
  metadata: [{ reasoning, usage, ... }] // See MessageWithMetadata type
});

If you are saving the message in a mutation and you have a text embedding model set, pass skipEmbeddings: true. The embeddings for the message will be generated lazily if the message is used as a prompt. Or you can provide an embedding upfront if it’s available, or later explicitly generate them using agent.generateEmbeddings.

Configuring the storage of messages

Generally the defaults are fine, but if you want to pass in multiple messages and have them all saved (vs. just the last one), or avoid saving any input or output messages, you can pass in a storageOptions object, either to the Agent constructor or per-message. The use-case for passing in multiple messages but not saving them is if you want to include some extra messages for context to the LLM, but only the last message is the user’s actual request. e.g. messages = [...messagesFromRag, messageFromUser]. The default is to save the prompt and all output messages.

const result = await thread.generateText({ messages }, {
  storageOptions: {
    saveMessages: "all" | "none" | "promptAndOutput";
  },
});

Message ordering

Each message has order and stepOrder fields, which are incrementing integers specific to a thread. User messages saved by saveMessage or generateText are added to the thread’s next order with a stepOrder of 0. Standalone assistant or tool messages append to the latest order by default. As response message(s) are generated in response to that message, they are added at the same order with the next stepOrder. To associate a response message with a previous message, you can pass in the promptMessageId to generateText and others. To start a standalone message at the next order, pass order: "next" to saveMessage or saveMessages. The component allocates that order atomically. To place a standalone message at a specific order, pass a number instead. If that order is empty, the first message is saved with stepOrder: 0; otherwise it is appended at the next stepOrder. order cannot be combined with promptMessageId or pendingMessageId; numeric orders must be non-negative safe integers less than Number.MAX_SAFE_INTEGER. Note: if the promptMessageId is not the latest message in the thread, the context for the message generation will not include any messages following the promptMessageId.

Deleting messages

You can delete messages by their _id (returned from saveMessage or generateText) or order / stepOrder. By ID:

await agent.deleteMessage(ctx, { messageId });
// batch delete
await agent.deleteMessages(ctx, { messageIds });

By order (start is inclusive, end is exclusive):

// Delete all messages with the same order as a given message:
await agent.deleteMessageRange(ctx, {
  threadId,
  startOrder: message.order,
  endOrder: message.order + 1,
});
// Delete all messages with order 1 or 2.
await agent.deleteMessageRange(ctx, { threadId, startOrder: 1, endOrder: 3 });
// Delete all messages with order 1 and stepOrder 2-4
await agent.deleteMessageRange(ctx, {
  threadId,
  startOrder: 1,
  startStepOrder: 2,
  endOrder: 2,
  endStepOrder: 5,
});

Other utilities:

import { ... } from "@bijection-dev/agent";

serializeDataOrUrl is a utility function that serializes an AI SDK DataContent or URL to a Bijection-serializable format.
filterOutOrphanedToolMessages is a utility function that filters out tool call messages that don’t have a corresponding tool result message.
extractText is a utility function that extracts text from a ModelMessage-like object.

Validators and types

There are types to validate and provide types for various values

import { ... } from "@bijection-dev/agent";

vMessage is a validator for a ModelMessage-like object (with a role and content field e.g.).
MessageDoc and vMessageDoc are the types for a message (which includes a .message field with the vMessage type).
Thread is the type of a thread returned from continueThread or createThread.
ThreadDoc and vThreadDoc are the types for thread metadata.
AgentComponent is the type of the installed component (e.g. components.agent).
ToolCtx is the ctx type for calls to createTool tools.

Get Started

Platform

Data and Operations

Guides

Client Libraries

Tools

API Reference

Retrieving messages

Showing messages in React

`useUIMessages` hook

UIMessage type

`toUIMessages` helper

Optimistic updates for sending messages

Saving messages

Without the Agent class:

Using the Agent class:

Configuring the storage of messages

Message ordering

Deleting messages

Other utilities:

Validators and types

​Retrieving messages

​Showing messages in React

​useUIMessages hook

​UIMessage type

​toUIMessages helper

​Optimistic updates for sending messages

​Saving messages

​Without the Agent class:

​Using the Agent class:

​Configuring the storage of messages

​Message ordering

​Deleting messages

​Other utilities:

​Validators and types

Retrieving messages

Showing messages in React

`useUIMessages` hook

UIMessage type

`toUIMessages` helper

Optimistic updates for sending messages

Saving messages

Without the Agent class:

Using the Agent class:

Configuring the storage of messages

Message ordering

Deleting messages

Other utilities:

Validators and types