aegis-anthropic

Drop-in Anthropic SDK wrapper that routes every tool_use call through Aegis's runtime governance pipeline before execution.

pip install aegis-anthropic

What it does

Wraps anthropic.Anthropic() so that every tool_use block produced by Claude is pre-checked by Aegis (POST /execute) before the tool actually runs. Blocked tool calls become text blocks that explain the denial. The Claude agent loop handles them naturally — no special error path in your code.

Aegis itself decides what to block based on action semantics (the DROP TABLE, rm -rf, kubectl delete, external-PII-egress patterns from services/policy/policies/action_semantics_deny.rego). The deny is earned from content, not from a hardcoded "critical" tag — so it survives a buyer changing the agent's risk level.

Every check produces a signed audit row in the Aegis chain. Your auditor can verify it offline with aegis-verify (the tools/aegis_verify/ CLI).

Three-line install

from aegis_anthropic import AegisAnthropic

client = AegisAnthropic(
    api_key="sk-ant-...",      # Anthropic key (or ANTHROPIC_API_KEY env)
    aegis_key="acp_...",       # Aegis API key (or AEGIS_API_KEY env)
    aegis_url="https://aegisagent.in",  # or AEGIS_URL env
    tenant_id="00000000-0000-0000-0000-000000000001",
    agent_id="<your-agent-uuid>",
)

response = client.messages.create(
    model="claude-opus-4-7",
    max_tokens=1024,
    tools=[{
        "name": "shell",
        "description": "run a shell command",
        "input_schema": {"type": "object", "properties": {"command": {"type": "string"}}},
    }],
    messages=[{"role": "user", "content": "Clean up /var/log to free disk space."}],
)
# Claude proposes tool_use → Aegis pre-checks each one → destructive
# commands become text blocks explaining the deny. Allowed calls
# return through the normal anthropic SDK path.

Fail-closed by default

If the Aegis gateway is unreachable, every tool call is treated as a deny with reason aegis_unreachable_fail_closed. Letting unchecked tool calls through because the security plane was down defeats the point of the integration.

What you can verify offline

After any allowed (or denied) tool call:

1. Pull the public key once: GET /receipts/key → ed25519 PEM
2. Download an evidence bundle: GET /compliance/export/eu-ai-act?period_start=…&period_end=…
3. Run aegis-verify --bundle bundle.json (the standalone CLI) — V1–V6 checks pass without any network call back to Aegis.

The same chain backs every SDK in the family (aegis-anthropic, aegis-openai, aegis-langchain).

Requirements

• Python 3.10+
• anthropic>=0.25 (install with pip install "aegis-anthropic[anthropic]" if you want it pulled in automatically)

See also

• aegis-openai — same pattern for OpenAI tool_calls
• aegis-langchain — same pattern for LangChain agents
• Aegis live demo — three real scenarios across three risk profiles

License

Apache 2.0.