Pre-tool intervention · PyPI 0.1.1 · Alpha · Apache-2.0

strands-acgs for Strands Agents.

Implements a Strands Agents intervention handler that checks tool arguments against an ACGS-Lite constitution before execution.

PyPI 0.1.1 GitHub repository Inspect src/strands_acgs/intervention.py#L23

Package Specification · Inspected HEAD f2aa974

Framework maintainer
AWS · strandsagents.com
Upstream repository
strands-agents/harness-sdk
PyPI release
strands-acgs==0.1.1
Python requirement
>=3.10
Framework constraint
strands-agents>=1.43.0
Governance engine pin
acgs-lite>=3.0.1,<4
Integration mechanic
Pre-tool veto / intervention hook
Hook entry point
ACGSIntervention.before_tool_call

01 · Local Setup & Quickstart

Attach governance to one tool-calling agent.

Install the pinned release from PyPI alongside acgs-lite>=3.0.1,<4. Rule evaluation uses deterministic keyword and regex matching locally in Python—no external model or network call is made by the governance check.

Caveat: Veto-only pre-call intervention; does not issue execution grants or outcome receipts.

Shell · PyPI installation

pip install "strands-acgs==0.1.1"

Python · Strands Agents integration

src/strands_acgs/intervention.py#L23
from strands import Agent
from strands_acgs import ACGSIntervention

agent = Agent(
    model=model,
    tools=[send_email],
    interventions=[ACGSIntervention()],
)

02 · Verdict & Review Mapping

How ACGS-Lite verdicts map to Strands Agents.

When a tool call is proposed, the adapter formats the tool name and arguments via format_tool_call and evaluates them against the configured Constitution. Blocking rules always take precedence over review rules.

Verdict.ALLOW

Returns the native Strands Proceed intervention action.

Verdict.DENY

Returns the native Strands Deny action with the violated ACGS rule explanation.

Verdict.REVIEW

Returns the native Strands Confirm action to trigger the Strands interrupt/confirmation flow.

03 · Public API Surface

Exported symbols and source entry points.

Each adapter keeps its public surface minimal and re-exports the shared GovernanceDecision, Verdict, and ToolCallFormatter types alongside the framework-specific hook or middleware class.

__all__ exports · strands-acgs

src/strands_acgs/intervention.py#L23 ↗
ACGSInterventionGovernanceDecisionToolCallFormatterVerdictformat_tool_call

Primary hook surface: ACGSIntervention.before_tool_call. Custom ToolCallFormatter functions may be supplied if your tool arguments require custom canonical serialization before rule matching.

04 · Scope & Bypass Boundaries

What this adapter does and does not cover.

Verify these framework-specific boundaries when integrating strands-acgs into an evaluation workflow.

All 13 adaptersReceipts, grants & EffectStore
  1. 01

    Requires strands-agents>=1.43.0 where the InterventionHandler protocol was introduced.

  2. 02

    Does not wrap the agent or tools directly; only tool calls routed through the agent's intervention pipeline are evaluated.

  3. 03

    In the current 0.1.x adapter series, rule evaluation runs through acgs-lite's ToolCallGovernor path. If your workflow requires SignedReceipt, ExecutionGrant, or SQLite EffectStore reservations, wire those contracts explicitly at the tool executor boundary.

Other pre-tool intervention packages

claude-agent-acgs0.1.0

Claude Agent SDK · Anthropic

openai-agents-acgs0.1.0

OpenAI Agents SDK · OpenAI

pydantic-ai-acgs0.1.0

Pydantic AI · Pydantic

adk-acgs0.1.1

Google ADK · Google

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