Simpul

Simpul (formerly SubagentBridge) is a native-first Model Context Protocol (MCP) subagent supervisor for supervised development workflows. It targets Google Antigravity IDE and other compatible MCP stdio hosts. Its architecture separates orchestration, worker identities, policy gates, evidence and local model transport.

Development candidate — 23 October 2026: This branch contains subagentbridge==1.0.0rc1 source, not a published or security-certified release. PR #3 remains open and targets PR #2's baseline branch. The default main still contains the older imported prototype.

What is implemented in this candidate

• Typed Run, Task, Dispatch, Evidence and approval contracts.

• SQLite-backed audit events, message bus and budget reservations with transaction controls.

• Policy classification, operation-bound approval broker and replay checks.

• Supervised read-only executor, bounded output and worker lifecycle components.

• PM → Developer → QA coordinator and evidence/receipt interfaces.

• Locally pinned skills registry with path and hash checking.

• Local-loopback 9Router text-client interface with explicit model discovery and budget bounds.

• MCP stdio server with run submission, readback, cancellation and diagnostic tools.

• Optional Orca integration seam; native mode does not depend on Orca.

Important: Presence of these modules and passing unit tests does not demonstrate that MCP submit_goal automatically executes a complete PM → Developer → QA workflow. In this branch submit_goal currently registers a SUBMITTED run and a PENDING task; it does not dispatch a worker in that handler.

Related MCP server: Roundtable AI MCP Server

Safety and evidence status

See project status and security limitations. Do not mark E18/E22/E23 verified from unit-test names alone.

Quick start — candidate branch

Requires Python 3.11–3.13 and Git. Example for PowerShell:

git clone https://github.com/rzqllh/SubagentBridge.git
cd SubagentBridge
git checkout 44d70b5f05836a867978dcadb166bd1122943a3b
python -m venv .venv
.\.venv\Scripts\python.exe -m pip install -e .
.\.venv\Scripts\python.exe -m unittest discover -s tests -p "test_*.py"
.\.venv\Scripts\python.exe -m subagentbridge.server

The last command runs an MCP stdio server and expects an MCP client; it does not open an interactive chat. Installing dependencies may access package indexes. Consult the installation guide for Linux and configuration considerations.

MCP host entry

Use the venv's Python interpreter, or launch your MCP host with that venv on PATH:

{
  "mcpServers": {
    "subagentbridge": {
      "command": "python",
      "args": ["-m", "subagentbridge.server"]
    }
  }
}

The display name is Simpul, but the MCP tool namespace, Python module, distribution, and SUBAGENTBRIDGE_* settings intentionally keep their existing technical identifiers. No mandatory migration/renaming is implied.

Exposed production-oriented MCP operations

submit_goal(goal, workspace_path=None, model=None), get_run(run_id), list_tasks(run_id), get_task_evidence(run_id, task_id), get_pending_approvals(), reject_approval(action_id, reason=""), get_model_usage(), and cancel_run(run_id, reason="").

The legacy session inspection endpoints remain available in this candidate, but legacy raw-runner execution paths are locked down. approve_action and apply_code_fix are not model-callable MCP tools; their compatibility functions deny privileged operations.

Documentation

• Developer roadmap, backlog, acceptance gates and next-session handoff

• Project status and evidence boundaries

• Installation

• MCP integration · API reference

• Architecture · Configuration

• Security / HITL · Confinement

• 9Router · Skills registry

• Compatibility and limitations

• Historical candidate test evidence

License and attribution

MIT · Third-party notices. Development history retains SubagentBridge names where required for traceability.