feat: add AG2 multi-agent framework integration

.github/workflows/ag2.yml

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+# This workflow comes from https://github.com/ofek/hatch-mypyc
+# https://github.com/ofek/hatch-mypyc/blob/5a198c0ba8660494d02716cfc9d79ce4adfb1442/.github/workflows/test.yml
+name: Test / ag2
+
+on:
+  schedule:
+    - cron: "0 0 * * *"
+  pull_request:
+    paths:
+      - "integrations/ag2/**"
+      - "!integrations/ag2/*.md"
+      - ".github/workflows/ag2.yml"
+  push:
+    branches:
+      - main
+    paths:
+      - "integrations/ag2/**"
+      - "!integrations/ag2/*.md"
+      - ".github/workflows/ag2.yml"
+
+defaults:
+  run:
+    working-directory: integrations/ag2
+
+concurrency:
+  group: ag2-${{ github.head_ref || github.sha }}
+  cancel-in-progress: true
+
+env:
+  PYTHONUNBUFFERED: "1"
+  FORCE_COLOR: "1"
+  OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
+  TEST_MATRIX_OS: '["ubuntu-latest", "windows-latest", "macos-latest"]'
+  TEST_MATRIX_PYTHON: '["3.10", "3.14"]'
+
+jobs:
+  compute-test-matrix:
+    runs-on: ubuntu-slim
+    defaults:
+      run:
+        working-directory: .
+    outputs:
+      os: ${{ steps.set.outputs.os }}
+      python-version: ${{ steps.set.outputs.python-version }}
+    steps:
+      - id: set
+        run: |
+          echo 'os=${{ github.event_name == 'push' && '["ubuntu-latest"]' || env.TEST_MATRIX_OS }}' >> "$GITHUB_OUTPUT"
+          echo 'python-version=${{ github.event_name == 'push' && '["3.10"]' || env.TEST_MATRIX_PYTHON }}' >> "$GITHUB_OUTPUT"
+
+  run:
+    name: Python ${{ matrix.python-version }} on ${{ startsWith(matrix.os, 'macos-') && 'macOS' || startsWith(matrix.os, 'windows-') && 'Windows' || 'Linux' }}
+    needs: compute-test-matrix
+    permissions:
+      contents: write
+      pull-requests: write
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: ${{ fromJSON(needs.compute-test-matrix.outputs.os) }}
+        python-version: ${{ fromJSON(needs.compute-test-matrix.outputs.python-version) }}
+
+    steps:
+      - name: Support longpaths
+        if: matrix.os == 'windows-latest'
+        working-directory: .
+        run: git config --system core.longpaths true
+
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install Hatch
+        run: pip install hatch
+
+      - name: Lint
+        if: matrix.python-version == '3.10' && runner.os == 'Linux'
+        run: hatch run fmt-check && hatch run test:types
+
+      - name: Run unit tests
+        run: hatch run test:unit-cov-retry
+
+      - name: Store unit tests coverage
+        if: matrix.python-version == '3.10' && runner.os == 'Linux' && github.event_name != 'schedule'
+        uses: py-cov-action/python-coverage-comment-action@7188638f871f721a365d644f505d1ff3df20d683 # v3.40
+        with:
+          GITHUB_TOKEN: ${{ github.token }}
+          COVERAGE_PATH: integrations/ag2
+          SUBPROJECT_ID: ag2
+          COMMENT_ARTIFACT_NAME: coverage-comment-ag2
+          MINIMUM_GREEN: 90
+          MINIMUM_ORANGE: 60
+
+      - name: Run integration tests
+        run: hatch run test:integration-cov-append-retry
+
+      - name: Store combined coverage
+        if: github.event_name == 'push'
+        uses: py-cov-action/python-coverage-comment-action@7188638f871f721a365d644f505d1ff3df20d683 # v3.40
+        with:
+          GITHUB_TOKEN: ${{ github.token }}
+          COVERAGE_PATH: integrations/ag2
+          SUBPROJECT_ID: ag2-combined
+          COMMENT_ARTIFACT_NAME: coverage-comment-ag2-combined
+          MINIMUM_GREEN: 90
+          MINIMUM_ORANGE: 60
+
+      - name: Run unit tests with lowest direct dependencies
+        if: github.event_name != 'push'
+        run: |
+          hatch run uv pip compile pyproject.toml --resolution lowest-direct --output-file requirements_lowest_direct.txt
+          hatch -e test env run -- uv pip install -r requirements_lowest_direct.txt
+          hatch run test:unit
+
+      - name: Nightly - run unit tests with Haystack main branch
+        if: github.event_name == 'schedule'
+        run: |
+          hatch env prune
+          hatch -e test env run -- uv pip install git+https://github.com/deepset-ai/haystack.git@main
+          hatch run test:unit
+
+  notify-slack-on-failure:
+    needs: run
+    if: failure() && github.event_name == 'schedule'
+    runs-on: ubuntu-slim
+    steps:
+      - uses: deepset-ai/notify-slack-action@3cda73b77a148f16f703274198e7771340cf862b # v1
+        with:
+          slack-webhook-url: ${{ secrets.SLACK_WEBHOOK_URL_NOTIFICATIONS }}

integrations/ag2/README.md

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+# ag2-haystack
+
+[![PyPI](https://img.shields.io/pypi/v/ag2-haystack.svg)](https://pypi.org/project/ag2-haystack/)
+
+An integration of [AG2](https://ag2.ai/) (formerly AutoGen) with [Haystack](https://haystack.deepset.ai/).
+
+AG2 is a multi-agent conversation framework with 500K+ monthly PyPI downloads, 4,300+ GitHub stars, and 400+ contributors. This integration brings AG2's powerful multi-agent orchestration capabilities into Haystack pipelines.
+
+## Installation
+
+```bash
+pip install ag2-haystack
+```
+
+## Usage
+
+### Standalone
+
+```python
+import os
+from haystack_integrations.components.agents.ag2 import AG2Agent
+
+os.environ["OPENAI_API_KEY"] = "your-key"
+
+agent = AG2Agent(
+    model="gpt-4o-mini",
+    system_message="You are a helpful research assistant.",
+)
+
+result = agent.run(query="What are the latest advances in RAG?")
+print(result["reply"])
+```
+
+### In a Haystack Pipeline
+
+```python
+from haystack import Pipeline
+from haystack_integrations.components.agents.ag2 import AG2Agent
+
+pipeline = Pipeline()
+pipeline.add_component("agent", AG2Agent(
+    model="gpt-4o-mini",
+    system_message="Answer questions clearly and concisely.",
+))
+
+result = pipeline.run({"agent": {"query": "Explain retrieval-augmented generation."}})
+print(result["agent"]["reply"])
+```
+
+## Parameters
+
+| Parameter | Type | Default | Description |
+|-----------|------|---------|-------------|
+| `model` | str | `"gpt-4o-mini"` | LLM model name |
+| `system_message` | str | `"You are a helpful AI assistant."` | System message for the assistant |
+| `api_key_env_var` | str | `"OPENAI_API_KEY"` | Env var name for the API key |
+| `api_type` | str | `"openai"` | API type (`"openai"`, `"bedrock"`, etc.) |
+| `max_consecutive_auto_reply` | int | `10` | Max auto-replies |
+| `human_input_mode` | str | `"NEVER"` | Human input mode |
+| `code_execution` | bool | `False` | Enable code execution |
+
+## License
+
+Apache-2.0 — See [LICENSE](../../LICENSE) for details.

integrations/ag2/examples/pipeline_example.py

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+import os
+from haystack import Pipeline
+from haystack_integrations.components.agents.ag2 import AG2Agent
+
+pipeline = Pipeline()
+pipeline.add_component("agent", AG2Agent(
+    model="gpt-4o-mini",
+    system_message="Answer questions clearly and concisely. Return TERMINATE when you have finished answering.",
+))
+
+result = pipeline.run({"agent": {"query": "Explain retrieval-augmented generation."}})
+print(result["agent"]["reply"])

integrations/ag2/pyproject.toml

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+[build-system]
+requires = ["hatchling", "hatch-vcs"]
+build-backend = "hatchling.build"
+
+[project]
+name = "ag2-haystack"
+dynamic = ["version"]
+description = "Haystack integration for AG2 multi-agent framework"
+readme = "README.md"
+license = "Apache-2.0"
+requires-python = ">=3.10"
+authors = [
+    { name = "deepset GmbH", email = "info@deepset.ai" },
+]
+classifiers = [
+    "Development Status :: 4 - Beta",
+    "License :: OSI Approved :: Apache Software License",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3.14",
+]
+dependencies = [
+    "haystack-ai",
+    "ag2[openai]>=0.11.4,<1.0",
+]
+
+[project.optional-dependencies]
+dev = [
+    "pytest",
+    "pytest-asyncio",
+    "ruff",
+    "mypy",
+]
+
+[tool.hatch.version]
+source = "vcs"
+tag-pattern = "integrations/ag2-v(?P<version>.*)"
+fallback-version = "0.1.0"
+
+[tool.hatch.version.raw-options]
+root = "../.."
+
+[tool.hatch.build.targets.wheel]
+packages = ["src/haystack_integrations"]
+
+[tool.hatch.envs.default]
+dependencies = [
+    "haystack-ai",
+    "ag2[openai]>=0.11.4,<1.0",
+    "pytest",
+    "pytest-asyncio",
+]
+
+[tool.hatch.envs.default.scripts]
+test = "pytest tests/ {args}"
+fmt = "ruff format src tests && ruff check --fix src tests"
+fmt-check = "ruff format --check src tests && ruff check src tests"
+lint = "ruff check src tests"
+types = "mypy src"
+
+[tool.hatch.envs.test]
+dependencies = [
+    "pytest",
+    "pytest-asyncio",
+    "pytest-cov",
+    "pytest-rerunfailures",
+    "mypy",
+    "pip",
+]
+
+[tool.hatch.envs.test.scripts]
+unit = 'pytest -m "not integration" {args:tests}'
+integration = 'pytest -m "integration" {args:tests}'
+all = 'pytest {args:tests}'
+unit-cov-retry = 'pytest --cov=haystack_integrations --reruns 3 --reruns-delay 30 -x -m "not integration" {args:tests}'
+integration-cov-append-retry = 'pytest --cov=haystack_integrations --cov-append --reruns 3 --reruns-delay 30 -x -m "integration" {args:tests}'
+types = "mypy -p haystack_integrations.components.agents.ag2 {args}"
+
+[tool.ruff]
+target-version = "py310"
+
+[tool.ruff.lint]
+select = ["E", "F", "I", "W", "UP"]
+
+[tool.mypy]
+python_version = "3.10"
+warn_return_any = true
+warn_unused_configs = true

integrations/ag2/src/haystack_integrations/components/agents/ag2/__init__.py

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+# SPDX-FileCopyrightText: 2024-present deepset GmbH <info@deepset.ai>
+#
+# SPDX-License-Identifier: Apache-2.0
+
+from haystack_integrations.components.agents.ag2.agent import AG2Agent
+
+__all__ = ["AG2Agent"]