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Antigravity CLI alternatives (2026)

Antigravity CLI: Google freemium terminal agent. Consumer successor to Gemini CLI; still Gemini-bound.

Its Catch: Vs Gemini CLI (OSS @google/gemini-cli): Antigravity is the product successor for free/Pro/Ultra consumers — not a 1:1 flag clone (MCP config paths differ).

Below: 8 free or free-tier tools from the same category (coding agents), free and open source first, then the closest match by shared tags. Each keeps its own Catch.

  1. 1.OpenCodeMIT OSS coding agent: CLI, TUI, desktop; BYOK/local

    Free / OSS · OSS/MIT · 217k GitHub stars

    VerdictMIT BYOK agent across CLI/desktop/IDE. The real catches are on /log: date stamp and compaction.

    CatchTwo catches worth reading on /log: “The date stamp is a trigger channel” (auto today’s-date × open-weight LoRA as a time-release fuse) and “Compaction ate the denial” (long sessions prune hard vetoes; compaction is untrusted rewrite). Re-read those two notes before you treat OpenCode as set-and-forget.

  2. 2.Kilo CodeMIT OSS IDE+CLI agent; active Cline/Roo line + MCP marketplace

    Free / OSS · OSS/MIT · 27.7k GitHub stars

    VerdictMIT IDE+CLI agent with MCP marketplace. Roo’s active heir, not a second OpenCode.

    CatchPitch IDE+platform, not “another OpenCode.” Gateway/account is convenience; BYOK stays. Marketplace and modes are the differentiator vs plain CLI harnesses. Enterprise governance rides Anaconda — evaluate if that middle layer matters for your org.

  3. 3.Open Code ReviewApache-2.0 hybrid deterministic+LLM review agent (MCP/plugins)

    Free / OSS · Apache-2.0 · 47.6k GitHub stars

    VerdictApache-2.0 hybrid review agent. Deterministic+LLM vs Semgrep/Gitleaks and vs general coding agents; BYO LLM.

    CatchVs Semgrep/Gitleaks (deterministic SAST/secrets): OCR adds an LLM agent layer for context-heavy review, not a drop-in replacement for static rules alone. Vs Claude Code/SWE-agent/OpenHands (general coding agents): OCR is a purpose-built review harness, not a full autonomous coder. BYO LLM cost — you bring the model endpoint and pay the provider; the OSS CLI itself is free.

  4. 4.Codex-XCodex-specific desktop and CLI workspace for visual configuration and MCP skills

    Free / OSS · OSS/MIT · 4.2k GitHub stars

    VerdictMIT Codex desktop/CLI companion. Handy for visual MCP and skills configuration; audit auth, relay endpoints, and unrestricted templates before trusting it.

    CatchVs T3 Code: Codex-X is Codex-specific visual configuration plus MCP/skills, not a broad remote coding environment or an independent coding model. It handles `auth.json`, supports third-party relays, and allows unrestricted prompt templates — review where credentials go, which endpoint receives requests, and what instructions can execute before using a release. Treat relays as a trust decision, not a convenience toggle.

  5. 5.Hex-Rays IDA MCPOfficial MIT MCP server for the IDA disassembler

    Free / OSS · OSS/MIT · 1.3k GitHub stars

    VerdictThe MCP to use if you already pay for IDA — everyone else should start with Ghidra.

    CatchThe server is free, but it needs IDA 9.4 or newer with idalib, which means a paid Hex-Rays licence (the community server says IDA Free is not supported). It is very young (created Aug 2026, date-stamped releases), and Hex-Rays recommends disabling other IDA MCP servers to avoid confusing the agent. If you don't own IDA, the free route is Ghidra with REA.

  6. 6.ripwireApache-2.0 offline code map and quality checks for coding agents (CLI + MCP)

    Free / OSS · Apache-2.0 · 2.5k GitHub stars

    VerdictA serious, offline repo map for agents — trust the evals doc over the marketing.

    CatchThe README is very long and leans on a field report written by a model about one engagement, which is not a controlled measurement; the repo has a separate EVALS doc, so read that instead. The one-line install pipes a script from GitHub into bash. Young and pre-1.0, and languages without a grammar fall back to weaker results, which it labels. It overlaps with Serena and Repomix for repo context.

  7. 7.OpenAI Codex CLIApache-2.0 OpenAI agent: CLI, IDE, app and cloud

    Free / OSS · Freemium · 130k GitHub stars

    VerdictOpenAI’s answer to terminal agents — open CLI, paid models; budget the plan or the API.

    CatchThe CLI is open source, but the models are not free: you pay through ChatGPT plan quotas or API spend. Codex Web runs on OpenAI’s cloud, not on your machine. The install.sh, brew and npm routes are supply-chain choices, so pin a release binary when that matters. Vs Claude Code or OpenCode: this is OpenAI’s first-party agent, tied to ChatGPT plans or OpenAI API keys.

  8. 8.Gemini CLIGoogle open-source terminal agent powered by Gemini

    Free / OSS · Apache-2.0 · 107k GitHub stars

    VerdictGoogle terminal agent. OSS CLI remains, but consumer quota was cut 2026-06-18; Antigravity (agy) is the consumer path. Gemini-bound by design.

    CatchGemini-bound lock-in—not model-agnostic like Goose or Crush. Consumer access (free/Pro/Ultra Google login) ended 2026-06-18; enterprise and API keys still work. Don't build on the old Google-login quota path. The OSS CLI remains. Antigravity CLI is the successor, not a 1:1 swap. Preview/nightly channels move fast; pin stable for production workflows. Enterprise path pushes you toward Vertex AI and Google Cloud project setup.

FAQ

What are the best free alternatives to Antigravity CLI?
OpenCode, Kilo Code, Open Code Review, Codex-X, Hex-Rays IDA MCP. All are reviewed on Stack Gems in the same category (coding agents); 8 free or open source.
What is the catch with Antigravity CLI?
Vs Gemini CLI (OSS @google/gemini-cli): Antigravity is the product successor for free/Pro/Ultra consumers — not a 1:1 flag clone (MCP config paths differ).
Is there an open-source alternative to Antigravity CLI?
Yes: OpenCode (OSS/MIT), Kilo Code (OSS/MIT), Open Code Review (Apache-2.0), Codex-X (OSS/MIT).

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