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

# Agent Builder Moving to Trueforge & Agent APIs Deprecated — v0.172

> In v0.172, the TrueFoundry agent builder moves to the Trueforge portal and the older Agent APIs are deprecated. Migrate to Trueforge APIs by 15th Oct, 2026.

> [!WARNING]
>
> **Applicable to:** Users who build or invoke agents with the TrueFoundry agent builder (the previous **Agents** sidebar section: Playground, Registry, and Sessions). If you do not use the agent builder, this change does not affect you.

## What Is Changing

The agent builder is moving out of the main TrueFoundry sidebar **Agents** section into a dedicated **Trueforge** portal. Open it from the sidebar under **TRUEFORGE → Build Agents**.

![TrueFoundry sidebar with the Agents section highlighted, showing Playground, Registry, and Sessions](https://mintcdn.com/truefoundry/Z86dKK-nvZeluIjE/images/docs/change-announcements/agents-sidebar-before.png?fit=max\&auto=format\&n=Z86dKK-nvZeluIjE\&q=85\&s=97e9a0eafb41b8e77065a0718da8ed1d)

![TrueFoundry sidebar with the TRUEFORGE section highlighted, showing Build Agents with a New badge](https://mintcdn.com/truefoundry/Z86dKK-nvZeluIjE/images/docs/change-announcements/trueforge-build-agents-after.png?fit=max\&auto=format\&n=Z86dKK-nvZeluIjE\&q=85\&s=da450bb540f6f8dc287ba8d969adde1f)

Clicking **Build Agents** opens the Trueforge portal — the managed agent builder experience:

![Trueforge portal showing New Chat, Build Agent, Agents, Sessions, and Schedules in the left navigation](https://mintcdn.com/truefoundry/Z86dKK-nvZeluIjE/images/docs/change-announcements/trueforge-portal.png?fit=max\&auto=format\&n=Z86dKK-nvZeluIjE\&q=85\&s=87eb07f843d8112a444ff8089e5b148e)

Trueforge is powered by our open-source agent harness ([truefoundry/trueforge](https://github.com/truefoundry/trueforge)). TrueFoundry provides a managed version of that harness in the platform.

### Self-hosted gateway planes

Trueforge runs on the control plane and talks to your default gateway to discover and use the models and MCP servers available to you. If you self-host the gateway plane, Trueforge will not work unless the control plane can reach that gateway plane.

> [!WARNING]
>
> If you self-host the gateway plane and the control plane cannot communicate with it, Trueforge will not work. Please [contact us](mailto:support@truefoundry.com) to get the connection set up if it is not already in place.

### Existing agents

Agents you built earlier with the agent builder are migrated automatically to Trueforge. Open **Build Agents** to find and continue working with them there.

### APIs

If you invoke agents via APIs, the older APIs continue to work until **15th October, 2026**. We recommend migrating to the [new Trueforge APIs](https://trueforge.dev/api/use-agent) as soon as possible.

## Why This Change

The agent builder is moving onto Trueforge so you get a dedicated portal for building and running agents, backed by the same open-source harness you can run yourself, with a managed experience on TrueFoundry.

## What You Need to Do

**1. Use Build Agents in the sidebar**

Go to **TRUEFORGE → Build Agents** instead of the previous **Agents** sidebar section (Playground, Registry, Sessions). Your existing agents appear in Trueforge after migration — no recreate step is required for agents built in the old builder.

**2. Check connectivity if you self-host the gateway plane**

Confirm that your control plane can reach your self-hosted gateway plane. If it cannot, Trueforge will not be able to list models or MCP servers — [contact us](mailto:support@truefoundry.com) to set the connection up.

**3. Migrate to the new Trueforge APIs**

Older agent APIs continue to work until **15th October, 2026**. Migrate to the [new Trueforge APIs](https://trueforge.dev/api/use-agent) as soon as possible.

## References

* [Trueforge (open source)](https://github.com/truefoundry/trueforge)
* [Use an agent — new APIs](https://trueforge.dev/api/use-agent)

***

If you have questions about the migration or run into anything unexpected, reach out to [**support@truefoundry.com**](mailto:support@truefoundry.com) — we're happy to help.


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