Show HN: AgentBridge – translate and govern calls between AI agent protocols
AgentBridge is an open-source Python project that acts as a translation and governance mesh between different AI agent protocols. It supports MCP, A2A, ACP, OpenAI function-calling, Gemini, and AGNTCY, and provides identity, budgets, audit trails, and a policy engine. It's a working prototype with 6 protocols and 150+ tests passing.
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One neutral mesh every agent speaks through: translate, route, verify, govern. Any protocol in, any protocol out — with identity, budgets, and a tamper-evident audit trail built into the call path.
The whole product in 12 seconds: an unknown agent blocked, six protocols reaching one live MCP tool through the mesh, budget tracked, tamper-evident audit chain verified. Reproduce with python examples/demo_story.py.
Status: working prototype. 6 protocols live + conformance-tested against real SDKs, a governance plane, an HTTP control plane, and framework integrations. 150 tests passing (156 with a Postgres DB). Business demand still being validated — this is an early, honest work-in-progress.
Name note: this project (github.com/shadowhunter-92/agentbridge) is a Python protocol-translation + governance mesh. It is unrelated to other products that may share the "AgentBridge" name (e.g. connector-gateway SaaS at other domains). This repo is the source of truth for this AgentBridge.
Table of contents
What it does · Quick start · Talk to agents yourself · Protocol support matrix · Architecture · Security model · Framework integrations · Enterprise governance · Editions & pricing · Docs
What it does
N-protocol mesh (any-to-any): MCP (Anthropic), A2A (Google/LF), ACP (IBM/LF), OpenAI function-calling, Gemini function-calling, AGNTCY ACP. One canonical model → adding a protocol is one adapter, not N² mappings. Every adapter is validated against the protocol's real official SDK.
In-line proxy: the bridge actually sits between live agents on different protocols, not just translating (see examples/).
Governance plane (the moat): Ed25519 agent identities (DIDs), per-agent spend/rate budgets, human-in-the-loop approvals for sensitive capabilities, and a hash-chained tamper-evident audit trail — all enforced in the call path and durable (SQLite; Postgres-swappable).
Enterprise governance: a declarative policy engine (cost caps, business-hours, route/ capability rules), RBAC for operators, OIDC/JWT operator SSO, and signed audit checkpoints (see docs/ENTERPRISE.md).
Drop-in MCP server: point Claude Desktop / an IDE / a gateway at it to reach other protocols.
Framework integrations: one helper lets LangChain / CrewAI / AutoGen / LlamaIndex agents reach a tool/agent on any protocol — they all emit OpenAI-shaped tool calls (see docs/INTEGRATIONS.md).
Quick start
python -m venv .venv && .venv/Scripts/pip install -r requirements.txt # (Windows; use bin/ on *nix)
Governance is optional. If you just want one agent/protocol to talk to another, use the mesh directly — no keys, no budgets, no setup:
from src.protocols import default_registry as reg from src.protocols.canonical import CanonicalCall
call = reg.get("openai").from_canonical_call(CanonicalCall("add", {"a": 2, "b": 3})) reg.translate_call(call, "openai", "mcp") # -> a real MCP tools/call. That's it.
.venv/Scripts/python examples/quickstart.py # translate + bridge to a LIVE tool, zero governance
Add identity, budgets, and a tamper-evident audit trail only when you want them:
Run the meta-bridge control plane (mesh + governance)
uvicorn src.api.control_plane:app # docs at http://localhost:8000/docs
set AGENTBRIDGE_ADMIN_KEY for operator endpoints; AGENTBRIDGE_DB=/path.db (or a postgres:// URL)
Or run it as a drop-in MCP server (stdio)
python -m src.serve.mcp_gateway
Live demos (real agents on both ends)
.venv/Scripts/python examples/live_nprotocol_proxy.py # OpenAI/ACP -> live MCP, MCP -> live ACP .venv/Scripts/python examples/live_governed_proxy.py # identity + budget + audit in action .venv/Scripts/python examples/policy_guardrails_demo.py # policy BLOCKS risky calls + provable audit trail
Tests
.venv/Scripts/python -m pytest tests/ -q # 150 passing; 156 with a Postgres DB (6 PG tests skip without one)
Talk to agents yourself (any protocol)
Yes — you can use AgentBridge to reach an agent/tool that speaks a different protocol than you do. That's the whole point. Give it a call in any protocol's shape; it translates and (if you want) governs, then delivers to the live target and hands the result back:
import asyncio from src.integrations import bridge_tool_call from src.proxy import transport
You "speak" OpenAI tool-calls; the tool lives behind MCP. Reach it anyway:
async def main(): result = await bridge_tool_call( "add", {"a": 2, "b": 3}, to="mcp", invoke=lambda w: transport.call_mcp_tool( "python", ["examples/mcp_server_agent.py"], w["params"]["name"], w["params"]["arguments"]), ) print(result) # -> OpenAI-shaped tool result: "5"
asyncio.run(main())
Swap to="mcp" for a2a, acp, gemini, or agntcy to reach an agent on that protocol.
Human client (discover + talk, from the CLI). Point it at any agent, see what it can do, and call it — across protocols:
Discover what an agent offers (MCP tools / A2A AgentCard):
python -m src.serve.agent_client discover --mcp "python examples/mcp_server_agent.py" python -m src.serve.agent_client discover --a2a http://localhost:9100
Call / talk to it:
python -m src.serve.agent_client call --mcp "python examples/mcp_server_agent.py" --tool add --args '{"a":2,"b":3}' python -m src.serve.agent_client talk --a2a http://localhost:9100 --message "hello"
Reaching real third-party tools (GitHub, Slack, Notion, …) works the same way — you point the bridge at the tool's existing MCP server, no connector to build. See docs/CONNECTORS.md and the worked GitHub example (examples/github_mcp_bridge.py).
Protocol support matrix
Protocol Owner Adapter Conformance vs real SDK Any-to-any Live agent
MCP Anthropic ✅ ✅ mcp 1.27 (CallToolRequestParams) ✅ ✅ FastMCP server (stdio)
A2A Google / LF ✅ ✅ a2a-sdk 0.3 (Task, Message) ✅ ✅ uvicorn agent + AgentCard
ACP IBM / BeeAI / LF ✅ ✅ acp-sdk 1.0 (Run, Message) ✅ ✅ REST /runs agent
OpenAI function-calling OpenAI ✅ ✅ openai 2.x (ChatCompletionMessageToolCall) ✅ ✅ routed to live MCP/ACP
Gemini function-calling Google ✅ ✅ google-genai (FunctionCall) ✅ ✅ routed to live MCP
AGNTCY ACP Cisco ✅ ✅ agntcy-acp (RunCreateStateless) ✅ ✅ routed to live MCP
ANP — ⛔ deferred → governance plane — — —
6 call protocols, 6×6 = 36 any-to-any pairs, all green. Adding a 7th is one adapter file + one registry line + one conformance test. Full detail: docs/PROTOCOL_SUPPORT.md. ANP is an identity/discovery layer, not a call protocol — it informs the governance plane, not an adapter (see docs/PROTOCOL_SUPPORT.md).
Architecture
flowchart LR subgraph clients [Agents / clients - any protocol] C1[MCP client] C2[A2A / ACP agent] C3[OpenAI / Gemini / AGNTCY] end subgraph bridge [AgentBridge] direction TB G[Governance gateway identity · budget · approval · audit] M[Canonical mesh any-to-any translation] G --> M end subgraph targets [Target agents / tools - any protocol] T1[live MCP tool] T2[live A2A / ACP agent] end C1 & C2 & C3 -->|signed call| G M -->|translated + governed| T1 & T2 OP[Operator] -->|admin API| G
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Every call enters the governance gateway (verify identity → reserve budget → check approval), is translated through the canonical mesh (any protocol → any protocol), is delivered to the target agent, then committed and written to a tamper-evident audit log.
src/protocols/ — canonical hub + per-protocol adapters (the mesh)
src/governance/ — identity, audit, budgets, approvals, policy, gateway, persistence (the moat)
src/proxy/ — real transport clients + in-line proxy
src/api/control_plane.py — the shipped HTTP API (mesh + governed routing, authenticated)
src/serve/mcp_gateway.py — drop-in MCP server packaging
Deployment topology: run it as a drop-in MCP server (per-developer), as a central control-plane API (team), or inline as a proxy between agents. See docs/DEPLOYMENT.md. Performance overhead is measured in docs/BENCHMARKS.md.
Security model
Operator endpoints require an admin key (X-Admin-Key) or — with OIDC configured — an IdP bearer token; every endpoint is RBAC-enforced (admin/operator/viewer).
Agent endpoints require Ed25519 signed requests (X-Agent-Id/X-Nonce/X-Signature) with nonce replay protection. Identities can be revoked.
Per-IP rate limiting on /control/* (blunts admin-key brute force; AGENTBRIDGE_RATE_LIMIT).
Audit is hash-chained and tamper-evident; export via /control/audit/export.
Persistence & multi-worker
Chosen from AGENTBRIDGE_DB: unset → in-memory; a file path → SQLite (single node); a postgres:// URL → Postgres (multi-instance; pip install "psycopg[binary]").
The audit-chain append and budget reserve/commit are atomic store-side operations (SQLite BEGIN IMMEDIATE / Postgres advisory locks), so multiple workers/replicas are safe when they share a durable store — the chain can't fork and budgets can't double-spend (tests/test_concurrency.py proves it across separate connections + threads). Use the in-memory store for single-worker/dev only. See docs/ENTERPRISE.md → Concurrency & scaling.
Framework integrations (LangChain / CrewAI / AutoGen / LlamaIndex)
These frameworks all emit OpenAI-shaped tool calls, so one helper lets any of them reach a tool/agent on any protocol through the bridge — zero new dependencies:
from src.integrations import bridge_tool_call
inside a LangChain/CrewAI/AutoGen tool:
result = await bridge_tool_call("add", {"a": 2, "b": 3}, to="mcp", invoke=your_transport)
Per-framework wrapping recipes (LangChain StructuredTool, CrewAI @tool, AutoGen function, LlamaIndex FunctionTool) are in docs/INTEGRATIONS.md.
Enterprise governance
Real, tested controls enterprises ask for — all live over the control-plane HTTP API:
Declarative policy engine — per-call cost caps, approval-above-cost, capability allow/deny, business-hours-only, blocked protocol routes (POST /control/policy/rules).
RBAC — admin / operator / viewer roles → permissions, enforced per endpoint.
OIDC / JWT operator SSO — verify an IdP token (Okta/Azure AD/Auth0/Keycloak), role claim → RBAC role; replaces the shared admin key.
Signed audit checkpoints — third-party-verifiable proof the audit log wasn't truncated; JSONL export feeds SIEMs (Splunk/Datadog/S3).
Full usage + code: docs/ENTERPRISE.md. (Honestly not shipped as code: managed hosting and SOC 2 — those are operations and an audit process, not a library feature.)
Governance in the call path: a policy blocks a forbidden capability, an over-budget call, and a needs-approval call — then a hash-chained, integrity-verified audit trail of every allow/deny. This is what EU AI Act Article 12 (automatic event logging for high-risk AI, from Aug 2026) looks like at runtime. Reproduce with python examples/policy_guardrails_demo.py.
▶ Watch the 54-second explainer (motion graphics + voiceover): shadowhunter-92.github.io/agentbridge/media/explainer.html — source: media/explainer.html.
Editions & pricing (direction)
Open-core: the mesh + basic governance are free and self-hostable (Apache 2.0). Monetization is hosted governance/compliance, not the translation (which is commoditizing). Indicative tiers (hypotheses to validate with customers, not live products):
Edition Who What Price (hypothesis)
OSS core builders mesh + basic governance + drop-in MCP server,
[truncated for AI cost control]