---
title: "Sessions, Runs & Streaming"
description: "The session and run contract you touch: continuation tokens, stream handles, the NDJSON event stream, and reconnecting."
---

Every Eve app speaks the same stable HTTP API to a [durable session](./execution-model-and-durability). This page is the contract you hold: the handles you get back, the events you stream, and how to reconnect.

## The two handles

Two handles do two jobs here, and mixing them up is the most common mistake. One handle creates and resumes a session; a different one streams and inspects it.

- **`continuationToken`**: the resume handle. Use it to send a follow-up message to the same conversation. Owned by the channel.
- **`sessionId` / `runId`**: the stream-and-inspect handle. Use it to attach to the event stream and watch a run. Owned by the runtime.

A session has one active continuation at a time: each follow-up uses the current `continuationToken`, and a stale one is rejected.

React, Vue, and Svelte apps reach for [`useEveAgent()`](../guides/frontend/overview) instead of calling these routes by hand. Next.js and Nuxt apps can proxy them to the Eve runtime from the same origin.

## Start a session

```bash
curl -X POST http://127.0.0.1:3000/eve/v1/session \
  -H 'content-type: application/json' \
  -d '{"message":"Summarize the latest forecast."}'
```

Eve responds right away. The JSON body carries a `sessionId` and a `continuationToken`, and the `x-eve-session-id` header tells you which durable session to stream.

## Stream a session

```bash
curl http://127.0.0.1:3000/eve/v1/session/<sessionId>/stream
```

The stream is newline-delimited JSON (NDJSON), one event per line:

| Event                     | Meaning                                                                                        |
| ------------------------- | ---------------------------------------------------------------------------------------------- |
| `session.started`         | A durable session was created.                                                                 |
| `turn.started`            | A new turn began.                                                                              |
| `message.received`        | An inbound user message was accepted.                                                          |
| `step.started`            | A model step began.                                                                            |
| `actions.requested`       | The model requested tool calls.                                                                |
| `action.result`           | A tool call returned.                                                                          |
| `input.requested`         | The run paused for human input (HITL approval or `ask_question`); carries `requests`.          |
| `subagent.called`         | A subagent was delegated; carries `childSessionId` to attach to.                               |
| `subagent.completed`      | A delegated subagent finished.                                                                 |
| `reasoning.appended`      | A reasoning delta (incremental, with cumulative text so far).                                  |
| `reasoning.completed`     | The finalized reasoning block.                                                                 |
| `message.appended`        | An assistant text delta (incremental, with cumulative text so far).                            |
| `message.completed`       | A finalized assistant text block.                                                              |
| `result.completed`        | The finalized structured result for a turn that requested an output schema; carries `result`.  |
| `compaction.requested`    | Context-window compaction began; carries `modelId`, `sessionId`, `turnId`, `usageInputTokens`. |
| `compaction.completed`    | A compaction checkpoint was written to durable history.                                        |
| `authorization.required`  | A connection needs OAuth; carries `name`, `description`, and an `authorization` challenge.     |
| `authorization.completed` | A connection's authorization resolved; carries `outcome`.                                      |
| `step.completed`          | A model step finished; carries `finishReason` and usage.                                       |
| `step.failed`             | A model step failed; carries `{ code, message, details? }`.                                    |
| `turn.completed`          | The turn finished.                                                                             |
| `turn.failed`             | The turn failed; carries `{ code, message, details? }`.                                        |
| `session.waiting`         | The session parked, waiting for the next input (a message, an answer).                         |
| `session.failed`          | The session failed.                                                                            |
| `session.completed`       | The session reached a terminal end.                                                            |

`reasoning.appended` and `message.appended` stream deltas as they arrive, and each one carries both the new delta and the cumulative text for the current block. The finalized block shows up on `message.completed` and `reasoning.completed`, which is the compatibility path for clients that don't render incremental streaming.

`message.completed` can fire more than once in a turn: the agent often emits interim assistant text before a tool call. To tell tool-call narration from a terminal reply, check `message.completed.data.finishReason`. `step.completed.data.finishReason` mirrors the step outcome, and usage lives on `step.completed`.

A delegated subagent publishes progress on its own child-session stream. The parent only emits `subagent.called` with a `childSessionId`, which a client uses to attach.

`step.failed` and `turn.failed` carry `{ code, message, details? }` for the failed fragment or turn, and `session.failed` is the terminal session-level variant. When a turn requested an output schema, the finalized payload lands on `result.completed` as `data.result` before the turn boundary. `authorization.required` carries the sign-in challenge (`data.authorization` may include `url`, `userCode`, `expiresAt`, `instructions`), and `authorization.completed` carries `data.outcome` (`"authorized" | "declined" | "failed" | "timed-out"`).

## Send a follow-up message

Once the session is waiting (you'll see `session.waiting`), POST your follow-up to the session endpoint with the stored continuation token:

```bash
curl -X POST http://127.0.0.1:3000/eve/v1/session/<sessionId> \
  -H 'content-type: application/json' \
  -d '{"continuationToken":"<token>","message":"Now send the short version."}'
```

The follow-up reuses the same durable session: same history, same state.

For deterministic ordering, send one follow-up at a time and wait for the next `session.waiting` event before sending another message to the same session. See [message delivery and queueing](./execution-model-and-durability#message-delivery-and-queueing) for the current runtime contract.

## Reconnect and rewind

The stream is durable. Every event is recorded before a step completes, so it's all replayable. Pass `startIndex` to reconnect by event count and pick up where you dropped off, or rewind to the start:

```bash
curl "http://127.0.0.1:3000/eve/v1/session/<sessionId>/stream?startIndex=<count>"
```

## Use the client from TypeScript

For scripts, server-to-server calls, tests, evals, and custom UIs, `eve/client` wraps these routes in a typed client so you don't hand-roll the POST and NDJSON stream loop.

Start with the [TypeScript SDK](../guides/client/overview) guide. It covers basic usage, sending messages, continuations, streaming, and per-turn `outputSchema` results.

## Inspect the agent over HTTP

`GET /eve/v1/info` returns a JSON inspection snapshot for the running agent: model, instructions, authored and framework tools, skills, channels, schedules, subagents, sandbox, connections, hooks, workflow, and workspace metadata. Local development accepts loopback requests; deployed Vercel targets require the route's OIDC auth.

```bash
curl http://127.0.0.1:3000/eve/v1/info
```

The route uses the same default auth chain as the eve channel (`[localDev(), vercelOidc()]`). Locally it answers anonymously; a deployed Vercel target requires a valid OIDC bearer, with a same-project bypass for in-deployment callers. See [auth & route protection](../guides/auth-and-route-protection).

## Dispatch order

Every stream event runs four steps, in this order:

1. **Channel handler**: the channel's event handler runs and can mutate adapter state.
2. **Metadata projection**: the framework re-evaluates the channel's `metadata(state)` and stores the result.
3. **Hooks**: authored [hooks](../guides/hooks) subscribed to the event fire.
4. **Dynamic resolvers**: [dynamic](../guides/dynamic-capabilities) tool, skill, and instruction resolvers fire, and `ctx.channel.metadata` already holds the freshly projected metadata from step 2.

The order isn't incidental, it's structural. By the time a resolver or hook reads channel metadata, the channel has already updated its state and the projection is current.

## What to read next

- [Execution model & durability](./execution-model-and-durability): what makes a session durable and how parked work resumes.
- [Channels](../channels/overview): what owns the continuation token and delivery.
- [TypeScript SDK](../guides/client/overview): call these routes from scripts and server-side code.
- [Frontend](../guides/frontend/overview): `useEveAgent` instead of raw routes.
