microsoft--agent-framework/dotnet/samples/04-hosting/FoundryHostedAgents/invocations/Hosted-Invocations-EchoAgent

Hosted-Invocations-EchoAgent

A minimal echo agent hosted as a Foundry Hosted Agent using the Invocations protocol. The agent reads the request body as plain text, passes it through a custom EchoAIAgent, and writes the echoed text back in the response. No LLM or Azure credentials are required.

Prerequisites

• .NET 10 SDK

Configuration

Copy the template:

cp .env.example .env

Note: .env is gitignored. The .env.example template is checked in as a reference.

Running directly (contributors)

This project uses ProjectReference to build against the local Agent Framework source.

cd dotnet/samples/04-hosting/FoundryHostedAgents/invocations/Hosted-Invocations-EchoAgent
dotnet run

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

Test it

curl -X POST http://localhost:8088/invocations \
  -H "Content-Type: text/plain" \
  -d "Hello, world!"

Expected response:

Echo: Hello, world!

Running with Docker

Since this project uses ProjectReference, the standard Dockerfile cannot resolve dependencies outside this folder. Use Dockerfile.contributor which takes a pre-published output.

1. Publish for the container runtime (Linux Alpine)

dotnet publish -c Debug -f net10.0 -r linux-musl-x64 --self-contained false -o out

2. Build the Docker image

docker build -f Dockerfile.contributor -t hosted-invocations-echo-agent .

3. Run the container

docker run --rm -p 8088:8088 hosted-invocations-echo-agent

4. Test it

curl -X POST http://localhost:8088/invocations \
  -H "Content-Type: text/plain" \
  -d "Hello from Docker!"

Deploying to Foundry (azd spec)

This sample includes an azd manifest (agent.manifest.yaml) and hosted agent spec (agent.yaml) for deployment to Foundry.

Initialize an azd project from this sample's manifest:

mkdir hosted-invocations-echo-agent && cd hosted-invocations-echo-agent
azd ai agent init -m https://github.com/microsoft/agent-framework/blob/main/dotnet/samples/04-hosting/FoundryHostedAgents/invocations/Hosted-Invocations-EchoAgent/agent.manifest.yaml

Then deploy:

azd deploy

If you need to override defaults, set deployment-time environment variables in the azd environment before deploying:

azd env set AGENT_NAME hosted-invocations-echo-agent
azd env set AZURE_AI_MODEL_DEPLOYMENT_NAME gpt-4o

For end-to-end hosted agent deployment guidance, see the official deployment guide.

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NuGet package users

If you are consuming the Agent Framework as a NuGet package (not building from source), use the standard Dockerfile instead of Dockerfile.contributor. See the commented section in Hosted-Invocations-EchoAgent.csproj for the PackageReference alternative.