> ## 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 If a page is wrong or out of date, report it with the MCP `submit_feedback` tool.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.

# Overview

> What the TypeScript Agent SDK is for and when to use it.

Use the TypeScript Agent SDK when your app needs more than one-shot generation:

* multi-step local tool loops
* resumable run state
* gateway-backed model turns
* validated structured outputs, streamed progress, and plugin-aware routing

It builds on top of `@phaseo/sdk` and defines the reference runtime contract shared by the other Agent SDK languages.

## Runtime capability matrix

| Capability | SDK support |
| - | - |
| Executable and concurrent tools | Built in, with deterministic result ordering and per-tool timeouts |
| Runtime validation | Input, output, event, and final agent schemas through `parse`, `safeParse`, or validator functions |
| Human approval | Per-tool or per-call approval with exact call-ID approval and rejection on resume |
| Human-in-the-loop tools | `onToolCalled` pause and `onResponseReceived` transformation |
| Manual tools | `execute: false` plus externally supplied `toolOutputs` |
| Progress-producing tools | Async-generator tools and `tool.preliminary_result` events |
| Tool error recovery | Fail the run or return a structured tool error to the model |
| Streaming | Model deltas plus replayable text, reasoning, item, tool, and full event consumers |
| Stop controls | Steps, duration, tokens, cost, tool call, finish reason, and custom predicates |
| Dynamic turns | Dynamic model, instructions, sampling values, tool sets, context mutation, and `nextTurnParams` |
| Durable continuation | Serializable run results or an application-owned `state` load/save accessor |
| Observability | Normalized usage and cost, warnings, finish reasons, step results, lifecycle events, and local devtools |

## What you get

* `createAgent()`
* `defineTool()`
* `createGatewayAgentClient()`
* `run()`, `stream()`, `continueRun()`, and `continueStream()`
* executable, manual, approval-gated, and human-in-the-loop tools
* runtime input/output schemas, generator progress, composable stop conditions, and usage/cost summaries
* optional application-owned state accessors and lifecycle events for devtools

## Next

* [Installation](https://phaseo.app/docs/v1/sdk-reference/typescript/agent-sdk-installation.md)
* [Usage](https://phaseo.app/docs/v1/sdk-reference/typescript/agent-sdk.md)


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.