# SDK overview

> See every agent that uses your API, and the step where it left or paid.

Source: https://docs.forgeintel.co/sdk/overview

Most of Forge works from the outside: it reads your website and docs, calls your API the way agents do, runs searches and simulations. The SDK sees what only your server sees: the agents that actually call your API, the session each one takes, and whether it ended in a paid call.

Add it to the API you already run. It works however agents pay you, and it only observes: your auth, pricing and payment code keep full control, and the SDK never changes a response.

  - [Quickstart](https://docs.forgeintel.co/sdk/quickstart): Install the SDK and confirm Forge receives events.
  - [Choose a stack](https://docs.forgeintel.co/integrations/overview): Express, Hono, Next.js, fetch handlers, FastAPI, or any ASGI app.

## What it adds

| | |
|---|---|
| **Agent identification** | Which agent made each request (Claude Code, Codex, Cursor and the long tail), from its headers and request patterns. |
| **Sessions** | Each agent's requests grouped into a session, from the first request to the step where it left or paid. It powers the [Activity](https://docs.forgeintel.co/activity) page. |
| **Agent context** | Optional, off by default: agents can tell you their name and the search that led them to you. [Agent context](https://docs.forgeintel.co/guides/agent-context). |
| **Discovery** | Your OpenAPI document and payment challenges are enriched so agents and indexes understand each route. [OpenAPI and discovery](https://docs.forgeintel.co/guides/openapi). |

The SDK never calls Forge on your response path, and a Forge outage never changes your responses. [See the request flow](https://docs.forgeintel.co/sdk/how-it-works).