> ## Documentation Index
> Fetch the complete documentation index at: https://phaseo.app/docs/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Phaseo Gateway base URL: https://api.phaseo.app/v1. Send `Authorization: Bearer $PHASEO_API_KEY` with every request.
> Model IDs look like `provider/model`, for example `openai/gpt-6-astra`. Do not guess IDs: list them with `GET /v1/models` or check https://phaseo.app/models. `phaseo/free` routes to an available free model and needs no wallet balance.
> For new text integrations prefer `POST /v1/responses`. `POST /v1/chat/completions` (OpenAI format) and `POST /v1/messages` (Anthropic format) suit existing code.
> The full API contract is https://phaseo.app/docs/openapi/v1/openapi.yaml. Official SDKs: `@phaseo/sdk` (TypeScript) and `phaseo` (Python), plus Go, C#, PHP, Ruby and Rust.
> Search these docs over MCP at https://phaseo.app/docs/mcp, and install Phaseo skills with `npx skills add https://phaseo.app/docs`. If a page is wrong or out of date, report it with the MCP `submit_feedback` tool.
> Manage Phaseo accounts with the `phaseo` CLI (`npm install -g @phaseo/cli`, then `phaseo login` or `phaseo login --device-code`), the `/v1` Management API or the MCP server at `https://mcp.phaseo.app/mcp?access=manage`. Do not send users to the dashboard for account tasks. A person is still needed for sign-up, approving a sign-in, paying the first top-up on the checkout link that `phaseo credits add` returns when no card is saved, confirming each saved-card top-up from the emailed link, and account security (password, MFA, passkeys). Create API keys with `phaseo keys create --name <name> --json`; never guess one. Credit top-ups need `phaseo login --scopes billing:write` first. Task map: https://phaseo.app/docs/v1/developers/manage-from-an-agent.md.

# Lifecycle hooks

> React to run, model, step, tool, and checkpoint events.

Use `onEvent` to update product interfaces, write audit records, or connect agent activity to your existing telemetry.

## Listen to a run

```typescript theme={null}
const result = await agent.run({
  input,
  client,
  onEvent(event) {
    console.log(event.type, event.runId);
  },
});
```

Keep event handlers small. Move slow network or storage work onto your application's queue when it should not delay the run.

## Event families

| Family | Events |
| - | - |
| Run | `run.started`, `run.resumed`, `run.waiting_for_human`, `run.cancelled`, `run.completed`, `run.failed` |
| Step | `step.started`, `step.completed`, `step.failed`, `step.cancelled` |
| Model | `model.requested`, `model.completed`, `model.failed` |
| Tool | `tool.started`, `tool.preliminary_result`, `tool.completed`, `tool.failed` |
| State | `checkpoint.saved` |

`step.completed` is emitted after the completed step has been checkpointed. This lets a persistence or telemetry consumer treat it as a stable boundary.

## Choose events for a product interface

* Use model deltas from [Streaming](https://phaseo.app/docs/v1/sdk-reference/typescript/agent-sdk-streaming.md) for live answer text.
* Use tool events for tool-call cards and progress indicators.
* Use `run.waiting_for_human` to show approval or input controls.
* Use terminal run events to close loading states and record outcomes.

## Related guides

* [Streaming](https://phaseo.app/docs/v1/sdk-reference/typescript/agent-sdk-streaming.md)
* [State and approval](https://phaseo.app/docs/v1/sdk-reference/typescript/agent-sdk-state-and-approval.md)
* [DevTools](https://phaseo.app/docs/v1/sdk-reference/typescript/agent-sdk-devtools.md)


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