Codex × Antigravity Collaboration

A practical reference architecture for coordinating native agent runtimes without introducing another orchestration framework.

Architecture website · Traditional Chinese README

This repository documents a working collaboration pattern built around Codex and Google Antigravity, with a path toward local models, privacy-aware routing, and multi-host execution.

It is intentionally not a new agent framework, scheduler, message bus, or enterprise security product.

Repository type: documentation-first reference architecture and case study. It captures architecture patterns, operational contracts, status, and design decisions from a working private reference setup. It is not an installable package and does not currently ship a standalone runtime.

The central idea is simple:

Use native agent capabilities first. Add coordination infrastructure only when the workload proves that it is needed.

Why this exists

Modern agent platforms are becoming capable in different ways:

• Codex provides strong coding workflows, parallel agents, worktrees, Skills, and engineering-oriented execution.
• Antigravity provides its own parallel subagents, custom agents, browser/Google integrations, Projects, Skills, MCPs, and hooks.
• Local models can cover private, offline, or network-restricted tasks.
• GitHub and Drive already provide durable shared workspaces for many asynchronous workflows.

The question is therefore less “which framework should coordinate everything?” and more:

How can existing runtimes cooperate while preserving their native strengths, limiting duplicated context, and keeping unnecessary infrastructure out of the critical path?

Design principles

1. Native capabilities first
   Do not rebuild parallel-agent or subagent features that the platforms already provide.

2. Capability-aware routing
   Route work to the runtime best suited to the task instead of sending every task to every model.

3. Bounded delegation
   A runtime may fan out internally, but cross-runtime delegation is hop-limited to prevent recursive agent chains.

4. Shared skills, thin adapters
   Reuse portable skills where possible. Keep platform-specific behavior in small adapters rather than duplicating the core method.

5. Progressive coordination
   Start with GitHub/Drive as a shared workspace. Add MCP/A2A-style explicit coordination only when needed. Add a broker only when retries, leases, heartbeats, or real-time state become actual requirements.

6. Distributed write ownership
   Many agents may read, analyze, and review. Conflicting write-sets should have one active owner at a time. Today this is a coordination policy, not a distributed-lock service: isolation relies on Git branches/worktrees and optimistic concurrency, with PR/review/merge as the conflict-resolution gate.

7. Privacy-aware routing
   Keep restricted data local. Where cloud use is appropriate, minimize and pseudonymize context before it crosses the trust boundary.

8. Roadmap is not implementation
   Every capability in this repository is labeled Implemented, Partial, Planned, or Exploratory.

Reference topology

flowchart TB
    H[Human / Coordinator]

    subgraph A["Codex environment"]
        C[Codex runtime]
        CP[Native parallel agents]
        CV[Role-based workers]
        C --> CP
        C --> CV
    end

    subgraph B["Antigravity environment"]
        AG[Antigravity runtime]
        AP[Native subagents]
        AR[Custom / role agents]
        AG --> AP
        AG --> AR
    end

    subgraph L["Local environment / restricted lane"]
        LM[Local model runtime]
        LT[Private or offline tasks]
        LM --> LT
    end

    H --> C
    H --> AG
    H --> LM

    C <-->|bounded external delegation| AG
    C -.->|optional local delegation| LM
    AG -.->|optional local delegation| LM

    G[(GitHub)]
    D[(Drive / shared documents)]

    C --- G
    AG --- G
    C --- D
    AG --- D

A key distinction is that a host or platform is not a single agent. Each runtime can already contain its own coordinator, role-based workers, and parallel agents. Cross-platform coordination therefore happens between agent runtimes, not merely between individual prompts.

See Architecture.

Current status

The status table is intentionally conservative. See Status and Roadmap.

Collaboration model

The architecture distinguishes four forms of collaboration:

1. Intra-runtime parallelism — platform-native parallel agents or subagents.
2. Vertical delegation — coordinator → specialized worker roles inside one runtime.
3. Inter-runtime delegation — Codex ↔ Antigravity, or another external runtime.
4. Inter-host delegation — the same pattern extended across machines.

Internal fan-out can be rich. External delegation is deliberately narrower.

Runtime A
├─ internal agent
├─ internal agent
└─ external delegation ──> Runtime B
                           ├─ internal agent
                           └─ internal agent

External delegation does not recursively bounce across runtimes without an explicit new decision.

Privacy-aware extension

The proposed trust model uses four data classes:

This is risk reduction, not risk elimination. Pseudonymization is not encryption-in-use, and remaining context may still support semantic re-identification.

Mature projects such as Presidio can supply sensitive-data detection primitives. A local model can optionally supplement deterministic rules by identifying organization-specific concepts that conventional PII detectors may not recognize. The local model should not be the sole policy authority.

See Privacy and Trust.

Coordination should evolve only when necessary

Stage 1 — Shared workspace
GitHub / Drive
        ↓
Stage 2 — Explicit coordination
MCP bridge / A2A-style agent communication
        ↓
Stage 3 — Brokered coordination
queue / state / lease / heartbeat / retry / timeout

The default is Stage 1 for low-frequency asynchronous work. Stage 2 and Stage 3 are upgrades, not prerequisites.

What this project deliberately does not build

• another multi-agent runtime;
• a universal scheduler;
• a custom distributed database;
• a vector database just for coordination;
• a new gateway when an existing bridge is sufficient;
• unrestricted recursive agent delegation;
• a claim of “fully autonomous” operation;
• a claim that pseudonymization makes cloud processing safe or compliant by itself.

Documentation

• Architecture
• Design Principles
• Privacy and Trust
• Status and Roadmap
• References

Traditional Chinese overview: README.zh-TW.md

Project maturity

This repository is best read as a reference architecture plus a working two-runtime case study.

The currently implemented core is Codex + Antigravity collaboration. Local privacy routing and distributed multi-host coordination are documented as future directions because the architecture should remain understandable before it becomes distributed.

License

MIT License. See LICENSE.