Eve

Eve is a filesystem-first framework for durable backend agents on Vercel.

You author an agent as a directory on disk. The directory is the contract:

• instructions.md defines the always-on instructions prompt
• skills/ define optional procedures
• tools/ define typed executable integrations
• connections/ define external MCP server connections
• sandbox/ overrides the agent's single sandbox (optional) and seeds workspace files
• channels/ define message ingress and delivery
• subagents/ define specialist child agents
• schedules/ define recurring jobs
• lib/ holds shared authored code
• agent.ts holds additive runtime config such as model, metadata, build, compaction, and workspace settings

The framework package is eve. The CLI binary is eve.

• Markdown-first authoring for instructions and procedures
• TypeScript where typed runtime behavior matters
• Durable message runs and follow-up turns
• Inspectable compiled artifacts under .eve/
• Per-agent sandbox with optional authored overrides
• A stable HTTP protocol with explicit continuationToken and sessionId contracts
• A runtime model that keeps channels, harnesses, and workflow execution separate

Eve’s internal split is:

• the channel normalizes inbound transport, applies auth and delivery policy, and owns continuationToken
• the harness does one unit of AI work and returns { session, next }
• the runtime persists state, follows next, streams events, and owns workflow primitives

That split is why the public HTTP protocol separates:

• continuationToken for the next user message
• sessionId for streaming and inspection

my-agent/
├── package.json
├── tsconfig.json
└── agent/
    ├── agent.ts
    ├── instructions.md
    ├── skills/
    ├── tools/
    ├── connections/
    ├── sandbox/
    ├── channels/
    ├── subagents/
    ├── schedules/
    └── lib/

agent/instructions.md

You are a weather-focused assistant. Be concise, accurate, and explicit when you use a tool.

agent/tools/get_weather.ts

import { defineTool } from "eve/tools";
import { z } from "zod";

export default defineTool({
  description: "Get the current weather for a city.",
  inputSchema: z.object({
    city: z.string(),
  }),
  async execute(input) {
    return {
      city: input.city,
      condition: "Sunny",
      temperatureF: 72,
    };
  },
});

agent/agent.ts

import { defineAgent } from "eve";

export default defineAgent({
  model: "openai/gpt-5.4-mini",
  name: "weather-agent",
});

npx eve@latest init my-agent

The command creates the project, installs its dependencies, initializes Git, and starts the development server. Add --channel-web-nextjs to scaffold the Web Chat application. If you already created an empty directory, run eve init, eve init ., or eve init ./ from inside it to run the same full scaffold there, including package.json. In a non-empty existing app, eve init . adds the agent files and missing dependencies instead; that add-agent flow requires an existing package.json. eve init does not create or link a Vercel project.

Useful commands:

• eve info shows discovery results and compiled artifacts
• eve init [name] creates a new agent
• eve build compiles .eve/ and builds the host output
• eve start serves the built .output/ app
• eve dev starts the local runtime and interactive terminal UI

Start here:

1. docs/README.md
2. docs/getting-started.mdx
3. docs/reference/project-layout.md
4. docs/agent-config.md
5. docs/reference/typescript-api.md
6. docs/connections.mdx

• packages/eve/README.md is the package-facing overview
• apps/fixtures/weather-agent is the weather-focused fixture used by local dev, smokes, and bundle analysis
• packages/eve/src/public/index.ts is the public API source of truth