> ## Documentation Index
> Fetch the complete documentation index at: https://agno-v2.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Tool Use

> Call WebSearchTools from Claude Sonnet 4 routed through the Nexus gateway.

> [!WARNING]
>
> The source routes requests to Anthropic's retired `claude-sonnet-4-20250514` model. Replace it with `anthropic/claude-sonnet-4-6` before running. See [Anthropic model deprecations](https://platform.claude.com/docs/en/about-claude/model-deprecations).

```python tool_use.py theme={null}
"""Run `uv pip install ddgs` to install dependencies."""

import asyncio

from agno.agent import Agent
from agno.models.nexus import Nexus
from agno.tools.websearch import WebSearchTools

# ---------------------------------------------------------------------------
# Create Agent
# ---------------------------------------------------------------------------

agent = Agent(
    model=Nexus(id="anthropic/claude-sonnet-4-20250514"),
    tools=[WebSearchTools()],
    markdown=True,
)

# ---------------------------------------------------------------------------
# Run Agent
# ---------------------------------------------------------------------------
if __name__ == "__main__":
    # --- Sync ---
    agent.print_response("Whats happening in France?")

    # --- Sync + Streaming ---
    agent.print_response("Whats happening in France?", stream=True)

    # --- Async ---
    asyncio.run(agent.aprint_response("Whats happening in France?"))

    # --- Async + Streaming ---
    asyncio.run(agent.aprint_response("Whats happening in France?", stream=True))
```

## Run the Example

<Snippet file="create-venv-step.mdx" />

**1. Install dependencies**

```bash theme={null}
uv pip install -U agno ddgs openai
```

**2. Export your API keys**

```bash Mac/Linux theme={null}
export ANTHROPIC_API_KEY="your_anthropic_api_key_here"
export OPENAI_API_KEY="your_openai_api_key_here"
```

```bash Windows theme={null}
$Env:ANTHROPIC_API_KEY="your_anthropic_api_key_here"
$Env:OPENAI_API_KEY="your_openai_api_key_here"
```

**3. Use a current Claude model**

Replace `anthropic/claude-sonnet-4-20250514` with `anthropic/claude-sonnet-4-6` in the saved file.

**4. Configure Nexus**

[Install Nexus](https://nexusrouter.com/docs/installation), then create `nexus.toml` for the Anthropic model and the `/llm/v1/` endpoint used by Agno:

```bash theme={null}
cat > nexus.toml <<'TOML'
[server]
listen_address = "127.0.0.1:8000"

[llm]
enabled = true

[llm.protocols.openai]
enabled = true
path = "/llm"

[llm.providers.anthropic]
type = "anthropic"
api_key = "{{ env.ANTHROPIC_API_KEY }}"

[llm.providers.anthropic.models."claude-sonnet-4-6"]
TOML
```

**5. Start Nexus**

Start the gateway from the directory that contains `nexus.toml`:

```bash theme={null}
nexus
```

**6. Run the example**

Save the code above as `tool_use.py`, then run:

```bash theme={null}
python tool_use.py
```

Full source: [cookbook/90\_models/nexus/tool\_use.py](https://github.com/agno-agi/agno/blob/v3.0.4/cookbook/90_models/nexus/tool_use.py)


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