microsoft--agent-framework/python/samples/04-hosting/foundry-hosted-agents/responses/04_foundry_toolbox

Agent with Foundry Toolbox (Responses Protocol)

An Agent Framework agent that uses Foundry Toolbox for tool discovery, hosted on Microsoft Foundry using the Responses protocol. Foundry Toolbox is a managed tool registry in Microsoft Foundry that lets you define tools centrally and share them across agents.

Creating a Foundry Toolbox

You can create a Foundry Toolbox by code. Refer to this sample for an example: Foundry Toolbox CRUD Sample.

You can also create a Foundry Toolbox in the Foundry portal. Read more about it in the Foundry toolbox documentation.

This sample consumes a toolbox over its MCP endpoint. It bundles a toolbox.yaml that defines 6 tools behind one endpoint:

• Web search, which grounds responses in real-time public web results.
• Code interpreter, which executes Python code in a secure sandbox and returns the output.
• Azure Specs MCP, which demonstrates connecting to an MCP server that doesn't require authentication.
• GitHub MCP, which demonstrates connecting to the GitHub MCP server using either a Personal Access Token (PAT) or OAuth2 (switch by changing the project_connection_id in toolbox.yaml).
• Azure Language MCP with agent identity, which demonstrates connecting to the Azure Language MCP server using agent identity for authentication.
• Microsoft Foundry MCP with Entra pass-through, which demonstrates connecting to the Microsoft Foundry MCP server using Entra pass-through for authentication.

Authentication Methods

You can connect to MCP servers in Foundry Toolbox that use different authentication methods. This sample demonstrates the following authentication methods:

• No authentication: The tool does not require any authentication. The agent can invoke the tool without providing any credentials. Sample MCP server: https://gitmcp.io/Azure/azure-rest-api-specs
• Key-based authentication: The tool requires a key to authenticate. Sample MCP server: https://api.githubcopilot.com/mcp (GitHub MCP server) with a Personal Access Token (PAT) for authentication.
• OAuth2 authentication (managed): The tool requires OAuth2 to authenticate. Sample MCP server: https://api.githubcopilot.com/mcp (GitHub MCP server) with OAuth2 for authentication.
• Agent identity authentication: The tool requires an agent identity token to authenticate. Sample MCP server: https://{foundry-resource-name}.cognitiveservices.azure.com/language/mcp?api-version=2025-11-15-preview (Azure Language MCP server) with agent identity for authentication.
• Entra Pass-through authentication: The tool requires an Entra pass-through token to authenticate; Foundry forwards the calling user's Entra token to the MCP server. Sample MCP server: the Microsoft Foundry MCP server, which exposes Foundry model-catalog, evaluation, agent, and session tools and requires only that the caller have access to the Foundry project (no extra license).

There are also Non-MCP tools in the toolbox that support different authentication methods. Learn more at the Foundry sample repository.

Finding the Entra audience for an MCP server

An Entra pass-through connection requires an audience — the Entra resource that the MCP server validates tokens against. For the Microsoft Foundry MCP server (https://mcp.ai.azure.com), read it from the server's OAuth protected-resource metadata:

curl https://mcp.ai.azure.com/.well-known/oauth-protected-resource

{
  "resource": "https://mcp.ai.azure.com",
  "authorization_servers": ["https://login.microsoftonline.com/common/v2.0"],
  "scopes_supported": ["https://mcp.ai.azure.com/Foundry.Mcp.Tools"]
}

Use the resource value (https://mcp.ai.azure.com) as the audience.

For connector-backed MCP servers (for example Microsoft 365 / WorkIQ servers such as Outlook Mail), the audience is instead published in the Foundry Tools Catalog. Look it up with the helper scripts in scripts/: run ./scripts/list-foundry-connectors.ps1 -ConnectorName <name> (or ./scripts/list-foundry-connectors.sh -n <name>) and read AzureActiveDirectoryResourceId (equivalently resourceUri) under properties.x-ms-connection-parameters. Run the script with no connector name to list every connector with its name, title, and auth type.

Creating Connections

Before creating the toolbox, create project connections for any tools that require authentication. The connection defines the authentication details and credentials for the tool, and the toolbox references the connection to authenticate tool invocations at runtime. The following connections are needed for this sample (used in toolbox.yaml):

For ghmcppat, run the following command to create a PAT-based connection to the GitHub MCP server:

azd ai connection create ghmcppat --kind remote-tool --target https://api.githubcopilot.com/mcp --auth-type custom-keys --custom-key "Authorization=Bearer <github_pat>" -p https://<account>.services.ai.azure.com/api/projects/<project>

For ghmcpoauth, create an OAuth2-based connection to the GitHub MCP server:

azd ai connection create ghmcpoauth --kind remote-tool --target https://api.githubcopilot.com/mcp --auth-type oauth2 --connector-name foundrygithubmcp -p https://<account>.services.ai.azure.com/api/projects/<project>

This sample uses ghmcppat by default, but you can switch to ghmcpoauth in the toolbox.yaml file.

For langmcpconn, create an agent-identity-based connection to the Azure Language MCP server:

azd ai connection create langmcpconn --kind remote-tool --target https://<language-service>.cognitiveservices.azure.com/language/mcp?api-version=2025-11-15-preview --auth-type project-managed-identity --audience https://cognitiveservices.azure.com/ -p https://<account>.services.ai.azure.com/api/projects/<project>

For foundrymcpconn, create an Entra pass-through connection to the Microsoft Foundry MCP server:

azd ai connection create foundrymcpconn --kind remote-tool --target https://mcp.ai.azure.com --auth-type user-entra-token --audience https://mcp.ai.azure.com -p https://<account>.services.ai.azure.com/api/projects/<project>

Creating the toolbox

You create the toolbox once from toolbox.yaml, then copy the versioned MCP endpoint it prints into the TOOLBOX_ENDPOINT environment variable. The agent connects to that endpoint at runtime.

azd ai toolbox create agent-tools --from-file ./toolbox.yaml --project-endpoint https://<account>.services.ai.azure.com/api/projects/<project>

How it works

Model Integration

The agent uses FoundryChatClient from the Agent Framework to create an OpenAI-compatible Responses client. It connects to the toolbox's MCP endpoint via MCPStreamableHTTPTool, which discovers and invokes the toolbox's tools over MCP at runtime. The agent resolves the endpoint from the TOOLBOX_ENDPOINT environment variable. If that variable isn't set, it builds the unversioned (default-version) endpoint from FOUNDRY_PROJECT_ENDPOINT and TOOLBOX_NAME.

See main.py for the full implementation.

Running the agent

Option 1: Azure Developer CLI (azd)

Prerequisites

1. Azure Developer CLI (azd) — Install azd (1.25 or later)
2. Install the unified Foundry CLI extension bundle (provides azd ai agent, connection, inspector, project, routine, skill, and toolbox):

   # If you previously installed individual extensions, uninstall them first:
   #   azd ext uninstall azure.ai.agents
   #   azd ext uninstall azure.ai.toolboxes
   azd ext install microsoft.foundry
   

3. Authenticate:

   azd auth login
   

Initialize the agent project

No cloning required. Create a new folder and initialize from the manifest:

mkdir my-toolbox-agent && cd my-toolbox-agent

azd ai agent init -m https://github.com/microsoft-foundry/foundry-samples/blob/main/samples/python/hosted-agents/agent-framework/responses/04-foundry-toolbox/agent.manifest.yaml

Follow the prompts to configure your Foundry project and model deployment. If you don't have an existing Foundry project, azd ai agent init will guide you through creating one. Initializing also sets the selected project as the active project for the azd ai commands that follow.

Create the toolbox with azd ai

Tip

If you use GitHub Copilot for Azure to scaffold a hosted agent that consumes this toolbox, the following skill references describe the same endpoint contract (env var, headers, MCP protocol, citation patterns, and troubleshooting) that the agent must implement:

• Toolbox reference — endpoint format, MCP protocol, OAuth consent handling, citation patterns, and troubleshooting.
• Use toolbox in a hosted agent — endpoint resolution, env-var contract, payload shape, code integration patterns, and tracing.

The agent reads the toolbox's MCP endpoint from TOOLBOX_ENDPOINT. Create the toolbox once from the bundled toolbox.yaml:

azd ai toolbox create agent-tools --from-file ./toolbox.yaml --project-endpoint https://<account>.services.ai.azure.com/api/projects/<project>

The first version becomes the default automatically. Use azd ai toolbox list, azd ai toolbox show agent-tools, and azd ai toolbox version list agent-tools to inspect, and azd ai toolbox delete agent-tools --force to remove it.

To stage incremental changes safely, use azd ai toolbox connection add/remove and azd ai toolbox skill add/list/remove; each creates a new toolbox version that carries forward existing connections and skills but doesn't change the default. Promote a version with azd ai toolbox publish agent-tools <version> when you're ready to make it active.

azd ai toolbox create prints the toolbox's versioned MCP endpoint. Copy that endpoint and store it in your azd environment so the agent connects to it:

azd env set TOOLBOX_ENDPOINT "https://<account>.services.ai.azure.com/api/projects/<project>/toolboxes/agent-tools/versions/1/mcp?api-version=v1"

Provision Azure resources (if needed)

If you don't already have a Foundry project and model deployment:

azd provision

Run the agent locally

azd ai agent run

The agent host will start on http://localhost:8088.

Invoke the local agent

In a separate terminal, from the project directory:

azd ai agent invoke --local "What tools do you have?"

Deploy to Foundry

Once tested locally, deploy to Microsoft Foundry:

azd deploy

For the full deployment guide, see Deploy a hosted agent.

Invoke the deployed agent

azd ai agent invoke "What tools do you have?"

Option 2: VS Code (Foundry Toolkit)

Prerequisites

1. VS Code with the Foundry Toolkit extension installed.
2. Sign in to Azure in VS Code.
3. The agent-tools toolbox must exist in your Foundry project. Create it from the bundled toolbox.yaml (azd ai toolbox create agent-tools --from-file ./toolbox.yaml) or in the Foundry portal before you run the agent.

Create the project

1. Open the Command Palette (Ctrl+Shift+P) and run Foundry Toolkit: Create Hosted Agent.
2. Select this sample from the gallery. The extension scaffolds the project into a new workspace and generates agent.yaml, .env, and .vscode/tasks.json + launch.json automatically.
3. Complete the Foundry Project Setup to pick the subscription and Foundry project (or create a new one).

Run and debug the agent

Press F5 to start the agent in debug mode. The agent host will start on http://localhost:8088.

Test with Agent Inspector

1. Open the Command Palette (Ctrl+Shift+P) and run Foundry Toolkit: Open Agent Inspector.
2. The Inspector connects to the running agent. Send messages to chat and view streamed responses.

Deploy to Foundry

1. Open the Command Palette (Ctrl+Shift+P) and run Foundry Toolkit: Deploy Hosted Agent. The extension opens a Deploy Hosted Agent wizard and reads agent.yaml to auto-populate settings.
2. If prompted, complete Foundry Project Setup to select subscription and project.
3. On the Basics tab, choose deployment method (Code or Container) and confirm the agent name.
4. On Review + Deploy, confirm runtime details, pick CPU and Memory size, and click Deploy.
5. After deployment, invoke the agent in the Agent Playground and stream live logs from the Logs tab.

Creating a Foundry Toolbox

You can create a Foundry Toolbox by code. Refer to this sample for an example: Foundry Toolbox CRUD Sample.

You can also create a Foundry Toolbox in the Foundry portal. Read more about it in the Foundry toolbox documentation.

Troubleshooting

A single failing MCP source can fail the whole agent

A toolbox aggregates every tool source behind one MCP endpoint. If any referenced MCP server fails while the toolbox enumerates tools (tools/list), the toolbox fails the entire enumeration, so the agent can't load its tools and every request returns an error (HTTP 500) until that source recovers.

For example, a flaky third-party MCP source can intermittently return HTTP 502 (Bad Gateway) during enumeration, which surfaces as:

tools/list failed for 1 tool source(s), succeeded for 5 tool source(s)
{"errors":[{"name":"<server_label>","type":"mcp","error":{"code":"HTTP_502", ...}}]}

This is an upstream/service hiccup, not a problem with the agent code. Mitigations:

• Retry the request — these failures are usually transient.
• If a source is persistently unavailable, temporarily remove its tool entry (and connection) from toolbox.yaml, recreate the toolbox, and update TOOLBOX_ENDPOINT.
• Inspect deployed agent logs with azd ai agent monitor to identify which source failed.

Entra pass-through forwards the caller's identity

The Foundry MCP tool authenticates with Entra pass-through (foundrymcpconn): Foundry forwards the calling user's Entra token to https://mcp.ai.azure.com. The token is forwarded both from the Foundry portal Agent Playground (signed-in user) and by azd ai agent invoke (the developer's Entra token), so the tools operate as that user and only act on resources the user can already access. The Foundry MCP server requires no extra license — just access to the Foundry project.

Because the tool acts as a specific user, running the agent locally (python main.py) or calling the endpoint with a raw token uses whatever identity that token represents (az login user locally, the agent's managed identity when hosted). If that identity has no access to the target resources, the tool returns an authorization error even though it is discovered and called correctly.

Some other Entra pass-through MCP servers add their own entitlement checks on top of the token. For example, the Microsoft 365 / WorkIQ servers (Outlook Mail, Teams) require the caller to hold a Microsoft 365 Copilot (Business Chat) license; without it they fail with WorkIQ license check failed. Required service plan(s): [M365_COPILOT_BUSINESS_CHAT]. That is a property of those servers, not of Entra pass-through itself.

Next steps

• Quickstart: Create a hosted agent — end-to-end walkthrough using azd
• Tool catalog — browse available tools to extend your agent (Bing Search, Azure AI Search, file search, code interpreter, and more)
• Manage hosted agents — monitor and manage deployed agents
• Basic agent — minimal agent with no tools
• Add local tools — sample with locally-defined Python tool functions
• Build multi-agent workflows — sample with chained agent pipelines