Clixad
Freemium
Developers who prefer terminal workflows
One agent deleted a production database during a code freeze. Another overwrote user files while reorganizing them — and neither left a record of exactly what it ran or why.
Overplane is a free, open-source CLI binary that wraps Claude Code, Codex, or OpenCode in container isolation, spec-driven builds, and Z3 formal verification before a single line of code is written. Every agent run executes in a locked-down container with a restricted view of the host system, so a bad outcome means deleting a sandbox, not restoring a backup. Builds are content-hashed and content-addressable, which means you can replay any build down to a single spec and see the normalized dollar cost attached to that run. The ceiling appears early in teams who need the tool to also do its own code generation — Overplane is a build wrapper around agents you already own, not a coding agent itself.
Bottom line: Pick this when auditability and container isolation are non-negotiable for your AI coding pipeline; plan around it when your team does not already have Claude Code, Codex, or OpenCode configured and does not want to manage multiple API keys.
Find your fit
More options in CLI Coding Agents. Compare pricing, platforms, and features side by side.
Freemium
Developers who prefer terminal workflows
Freemium
Developers preferring fully local agent execution
Overplane is a single-file, Apache-2.0-licensed binary that turns AI coding agents into a build system. The workflow starts with numbered Markdown specs as the source of truth: schema-validated, git-diffable, and the only input the build consumes. From there, the tool lifts each spec into an Intermediate Representation, runs Z3 to check for contradictions across per-spec and merged models before any code is written, then passes the checked IR alongside the original spec to the agent. The agent runs inside a container image you build and control; if the run succeeds, Overplane reconciles the output. The vendor’s rustdis example — a wire-compatible Redis clone — shows the checked IR producing 48 passing property tests and Kani proof harnesses.
The differentiating feature is what the vendor calls a real build system for codegen: content-hashed sandbox images and content-addressable outputs make every build cacheable, incremental, and replayable down to an individual spec. Most spec-driven tools are Markdown prompts riding inside an agent with no record of which run produced what. Overplane treats that as the same problem compilation solved decades ago — the compiler just happens to be an agent.
Overplane fits teams who have already chosen an agent — Claude Code, OpenAI Codex, or OpenCode — and want container isolation, formal spec verification, and a reproducible audit trail layered on top. It does not replace the agents; it drives them headlessly on your own API keys, letting you swap agents per project or per run. The gap appears when a team needs an out-of-the-box coding agent with no prior key management or agent setup — Overplane offers neither. Teams that hit that wall look at the agents directly or at hosted wrappers that bundle the agent subscription alongside the build tooling.
The tool is distributed as a standalone binary described on the vendor page as v0.0.8. There is no API surface, no hosted offering, and no paid tier referenced. Multi-agent support allows different agents per project or per run, with normalized cost tracking across all of them so you can compare what each agent spent on the same spec set.
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