Forall vs improv.sh

Forall and improv.sh are both cli coding agents tracked by AIDiveForge. Below is a side-by-side comparison of pricing, capabilities, platforms, and ownership — sourced from each tool's live website and verified before publishing.

Forall

Forall is an Apache-2.0 CLI agent from Astrio that generates spec-driven code alongside machine-checkable proofs, running entirely in your terminal or wiring into Cursor, Claude Code, or Codex via MCP. You describe what the code must do; the agent produces both the implementation and a formal proof you can verify independently. The verification step is not optional decoration — it runs against the spec, so a failing proof surfaces a real logical flaw before the code ships. The docs describe Rust, TypeScript, and Java as the supported targets, which covers a specific but meaningful slice of production codebases. Teams outside those languages hit a hard wall.

improv.sh

improv operates as a task harness: the @im call pulls repo context, detects your test commands, writes acceptance criteria, and packages shell validation steps into one spec the agent can implement on turn one. The loop infrastructure is the distinguishing piece — judges run your actual exit-code commands (npm test, typecheck, build), so done means your tests pass, not that the agent says it's done. The tool installs locally via curl with no external API keys required, and the Chrome extension brings the same engine into web-based chat interfaces. The 920-skill library and daily auto-research loop suggest the routing layer will keep growing — but the page offers no independent benchmarks to validate the token-savings figures cited.

Attribute	Forall	improv.sh
Pricing	Paid	Free
Free trial	No	No
Open source	Yes	Yes
Has API	Yes	No
Self-hosted option	Yes	Yes
Platforms	CLI, terminal, MCP clients	VS Code, Cursor, Claude Code, terminal, Chrome
Released	2026-07-17	—
Pros	Generates machine-checkable proofs alongside code, so correctness is verifiable by a tool rather than trusted on faith — eliminating the class of bugs that pass all tests but violate the spec. Apache-2.0 license with a self-hosted CLI path, which means the proof pipeline runs on your infrastructure without sending proprietary specs to a third-party service. MCP integration drops the agent directly into Cursor, Claude Code, or Codex via a config block, so teams avoid a context switch to a separate tool when they want verification mid-session. Spec-driven generation disciplines the coding workflow upfront, which means the spec ambiguities that normally surface in code review get resolved before the first line is written. Agentic execution runs specs-to-proof autonomously in the terminal, so verification does not require manual orchestration between separate tools for generation and checking.	Repo-aware spec compilation pulls your actual test commands and package scripts into the task before the agent starts, which means the agent implements against your real constraints instead of inventing them mid-run. Exit-code judges close the loop on real shell commands — npm test, typecheck, build — so you are not relying on the agent's self-assessment of whether it finished. Task memory persisted under .improv/tasks/ survives session boundaries, so an agent restarted mid-task picks up status and spec instead of starting the discovery cycle again. Local-first install with no external API keys required, which means the harness runs in air-gapped or locked-down environments where cloud tooling is blocked. Chrome extension and VS Code/Cursor Marketplace extension share the same local engine, so the spec compilation and judge loop work whether you are in the IDE or a browser-based chat interface — without switching tabs.
Cons	Language support is limited to Rust, TypeScript, and Java — a Python, Go, or C++ team gets zero proof generation, and the vendor page describes no roadmap for expansion, leaving those teams with no path forward except switching to a different verification approach entirely. Spec-driven development requires writing formal specifications before generating code; teams without prior exposure to this discipline spend non-trivial time learning to write specs that are precise enough for the proof system to use, at which point the productivity argument against traditional TDD weakens. Teams whose correctness requirements are satisfied by property-based testing tools — like QuickCheck for Haskell or Hypothesis for Python — have an established, language-native alternative that does not require adopting a new agent layer and may switch there rather than retrofit Forall into an incompatible stack.	Task state is written to .improv/tasks/ on the local machine. Teams with more than one developer working the same codebase have no shared task state — there is no sync layer described on the page — so parallel agent runs on different machines produce divergent task records with no reconciliation path. The tool exposes no API surface, so teams that want to trigger improv from a CI pipeline or wrap it in a custom orchestration layer cannot. Teams hitting this wall move to harness frameworks that expose programmatic interfaces — at which point they are maintaining the prompt compilation logic themselves. The token-savings figures on the page (~613 tokens median) are vendor-reported with no independent reproduction methodology described. Teams making adoption decisions based on cost reduction should treat these numbers as illustrative until they run their own baseline comparison. Chrome extension installation requires either the Chrome Web Store or a manual sideload script — neither path is available in Firefox or Safari. Teams on non-Chromium browsers are limited to the terminal install, losing the browser chat integration entirely.

Bottom line

Forall is paid while improv.sh is free; only Forall exposes a public API. Choose based on which difference matters most for your workflow.

Frequently asked questions

What is the difference between Forall and improv.sh?

Forall is Paid and open source, while improv.sh is Free and open source. Compare pricing, free trial, API, platforms, and pros/cons in the table above on AIDiveForge.

Is Forall better than improv.sh?

It depends on your workflow. Use the side-by-side attributes (pricing, open source, API, self-hosted, platforms) to decide. AIDiveForge does not rank a universal winner — we publish verified facts so you can choose.