Responsibility Pathway Runtime

Govern external actions without losing evidence, recovery, or the human decision point.

Responsibility Pathway Runtime (RPR) is an MIT-licensed Python runtime for applications that need to place an explicit responsibility pathway in front of consequential external actions. It preserves actor and authority declarations, execution-attempt continuity, readback evidence, fail-closed ambiguity handling, repair routes, and Human Gate decisions.

Public Alpha — 0.1.0a4
Tag: v0.1.0a4
Correction scope: package-description and release-metadata alignment after 0.1.0a3
RPR is not a legal-responsibility engine, identity provider, secret manager, production gateway, or guarantee of exactly-once effects across arbitrary remote systems.

PyPI · GitHub Prerelease · Product site · Live browser demo · MCP integration · Article 50 profile · 日本語の入口 · Quick Start · Report an issue

Why RPR

AI agents and automation can execute faster than people can reconstruct what happened. RPR provides a bounded runtime layer where an integrating application can:

• declare actors, authority, and the proposed action;
• evaluate and retain an explicit pathway state;
• bind operations, attempts, and idempotency identity;
• require independent readback before completion;
• stop ambiguous writes as write_status_unknown instead of false success;
• retain Human Gate, repair, resume, reconciliation, and evidence continuity;
• survive restart without silently repeating unresolved effects.

Current MCP support

The published package includes two distinct MCP-related boundaries.

Governed outbound MCP calls

A host application can route consequential outbound MCP tool calls through an RPR responsibility pathway. The verified path includes local subprocess launch, stdio transport, MCP JSON-RPC framing, admitted server and tool bindings, execution-attempt continuity, fail-closed ambiguous outcomes, and optional independent readback.

A successful MCP response is not automatically proof of a consequential external effect. When required readback is missing or transport failure leaves dispatch uncertain, RPR retains write_status_unknown rather than silently retrying or reporting success.

Published read-only MCP inspection server

The package includes rpr-mcp, a local stdio read-only inspection server targeting stable MCP protocol version 2025-11-25.

rpr-mcp --database ./rpr.sqlite3

It exposes only:

rpr.get_status
rpr.list_pathways
rpr.get_pathway
rpr.get_evidence
rpr.list_unresolved

It has no approval, execution, transition, reconciliation, repair, or resume tool. The SQLite database is opened in read-only mode. Access is intended only for a trusted local MCP client that already has operating-system permission to read the database.

Support for mutating MCP tools, remote MCP transport, and later draft or release-candidate MCP protocol versions is not claimed.

EU AI Act Article 50 transparency profile

RPR includes an optional Article 50 profile that records and evaluates integrator-declared disclosure, marking, labelling, editorial-review, and Human Gate evidence through structured fail-closed outcomes.

This profile does not provide legal classification, legal advice, certification, or a declaration of compliance with the EU AI Act. Jurisdiction-specific interpretation and deployment decisions remain with the responsible operator and legal advisers.

Verified public-alpha scope

• pathway registration and authorized state transitions;
• persistent pathway and execution-attempt stores;
• Human Gate, repair, resume, and reconciliation boundaries;
• local-file, allow-listed HTTP, durable outbound-message, and real MCP subprocess paths;
• published read-only MCP inspection server and rpr-mcp CLI;
• MCP protocol-abuse, malformed-input, notification, subprocess, and database-byte-invariance tests;
• Article 50 profile, executable sample, public API exports, and focused tests;
• crash/restart continuity and duplicate-dispatch prevention;
• wheel and source-distribution build and clean-install checks;
• English-primary and Japanese-parallel documentation;
• selected Lean 4 state-machine invariants;
• Chromium and Pyodide execution of the CI-built wheel.

ER-1 hardening has started but is not complete. Customer proxy, TLS, identity, credentials, independent MCP clients, operating-system permission profiles, long-duration operation, production supervisors, and customer-equivalent connectivity remain external-environment validation items.

The evidence ledger is tamper-evident, but it is not independently signed, externally immutable, or independently timestamped. No production-ready or enterprise-ready claim is made.

Quick Start

Install the public alpha in an isolated environment:

python3.11 -m venv .venv
. .venv/bin/activate
python -m pip install --upgrade pip
python -m pip install responsibility-pathway-runtime==0.1.0a4
rpr --help
rpr-mcp --help

For development or source inspection:

git clone https://github.com/YutoriKomeiji/responsibility-pathway-runtime.git
cd responsibility-pathway-runtime
python -m pip install -e .

Integration boundary

The host application remains responsible for authentication, credential isolation, network controls, bypass prevention, domain-specific authorization, MCP peer selection, tool permissions, trusted-client access to stored pathway data, and independent readback sources. RPE integration is optional; RPE absence, malformed output, or unsupported results must not become implicit permission.

Field-test reports

Please report reproducible findings for operating systems, containers, Python environments, proxy/TLS/identity boundaries, independent MCP clients, framework integrations, installation and removal, backup and restore, and documentation gaps. A user report is evidence for that environment; it does not imply universal production readiness.

Documentation

• Product, scope, and architecture
• MCP integration
• Article 50 profile
• Installation, operations, and recovery
• Security, limitations, integration, and API
• Verification, known issues, release notes, and UAT
• Support and field testing
• Security reporting
• Contributing

License

RPR is released under the MIT License. Copyright © 2026 Akihisa Ono.