Open Harness

npm install @openharness/core @ai-sdk/openai

import { Agent, createFsTools, createBashTool, NodeFsProvider, NodeShellProvider } from "@openharness/core";
import { openai } from "@ai-sdk/openai";

const agent = new Agent({
  name: "dev",
  model: openai("gpt-4o"),
  tools: {
    ...createFsTools(new NodeFsProvider()),
    ...createBashTool(new NodeShellProvider()),
  },
  maxSteps: 20,
});

for await (const event of agent.run([], "List all TypeScript files and count lines")) {
  if (event.type === "text.delta") process.stdout.write(event.text);
}

import { Session } from "@openharness/core";

const session = new Session({ agent, contextWindow: 128_000 });

for await (const event of session.send("List all TypeScript files")) {
  if (event.type === "text.delta") process.stdout.write(event.text);
}
for await (const event of session.send("Now refactor the largest one")) {
  if (event.type === "text.delta") process.stdout.write(event.text);
}

import { Conversation, toRunner, apply, withTurnTracking, withCompaction, withRetry } from "@openharness/core";

const runner = apply(
  toRunner(agent),
  withTurnTracking(),
  withCompaction({ contextWindow: 200_000, model: agent.model }),
  withRetry({ maxRetries: 5 }),
);

const chat = new Conversation({ runner });
for await (const event of chat.send("Fix all linting errors")) { /* ... */ }

{
  "mcpServers": {
    "open-harness": {
      "command": "npx",
      "args": ["-y", "@openharness/core"],
      "env": {
        "OPENAI_API_KEY": "your-openai-api-key"
      }
    }
  }
}