Delta Agents Docs

Delta is designed around port adapters for storage, model access, and messaging. Defaults let you work immediately; adapters let you connect real infrastructure.

Storage adapters

In-memory store

Default. All data lives in memory for the lifetime of the engine. No setup required.

import { createInMemoryStore } from "delta-agents";

const delta = await createDeltaEngine({
  store: createInMemoryStore(),
});

Best for development and testing. Data is lost when the process exits.

Drizzle SQLite store

Persistent storage using Drizzle ORM with libsql (SQLite). Suitable for single-process deployments.

import { createDrizzleStore } from "delta-agents";
import { createClient } from "@libsql/client";

const client = createClient({ url: "file:./delta.db" });
const delta = await createDeltaEngine({
  store: createDrizzleStore({ client }),
});

The Drizzle adapter requires the Drizzle ORM packages and libsql client as dependencies. The store methods are optional: missing methods skip gracefully with a warning, so the adapter works even when a table has not been migrated yet.

Both adapters support the full set of optional cleanup methods (deleteTask, deleteMessages, getTasksOlderThan, getTaskIds), enabling the delta.cleanup() lifecycle.

Reasoner adapters

OpenAI reasoner

Default when models are configured. Uses the OpenAI API or any OpenAI-compatible endpoint.

The engine resolves the model from the agent's model field, looks up the ModelDef configuration, and calls the provider with the resolved endpoint, API key, and options. If the model's vision or audio flags are set, the reasoner embeds image or audio attachments as content parts.

Mock reasoner

For testing without a live model API.

import { createMockReasoner } from "delta-agents";

const reasoner = createMockReasoner({
  respondWith: {
    kind: "action",
    name: "lookup-customer",
    input: { customerId: "C-42" },
  },
});

The mock reasoner always returns the configured response, making tests deterministic and fast.

Custom reasoner

Implement the ReasonerPort interface to use any model provider.

type ReasonerPort = {
  reason: (input: ReasonerInput) => Promise<Result<ReasonerDecision, string>>;
};

Channel adapters

Chat SDK channel

Bridges agents to messaging platforms using the Chat SDK ecosystem.

import { createChatSdkChannel } from "delta-agents";

const slackChannel = createChatSdkChannel({
  type: "slack",
  adapter: slackAdapter,
});

const supportAgent = delta.agent({
  name: "support-agent",
  channels: [slackChannel],
});

The Chat SDK adapter works with Slack, Teams, Discord, and Telegram through a single interface. Cross-platform conversation continuity is maintained: agents track context regardless of which channel the user switches to.

Adapters