Forall vs Mycelium

Forall and Mycelium 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.

Mycelium

The core problem Mycelium targets is the agent that sprints from idea to pull request without asking why the feature exists, who asked for it, or whether the scope is right. The tool inserts a structured discovery phase — sequential questions, evidence gathering, a brief — that the agent must complete before code generation begins. The vendor describes it as earning the right to start. It runs as a Claude Code plugin and is MIT-licensed, so you install it, keep the source, and own the workflow. The wall appears when your project outgrows Claude Code itself: teams that move to a different agent runtime drop Mycelium entirely because it has no standalone API and no runtime outside that harness.

Attribute	Forall	Mycelium
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	Claude Code
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.	Inserts a structured discovery phase before code generation begins, so the agent cannot skip from idea to pull request without accounting for purpose and audience — the exact pattern that produces features nobody asked for. Produces a written decision brief as part of the workflow, which means scope decisions are documented at the moment they are made rather than reconstructed from memory in a post-mortem. MIT-licensed with self-hosted deployment and no external API dependency, so you audit the full workflow, modify it, and run it without a vendor in the data path. Designed specifically for Claude Code's plugin system, so setup is a single install command rather than a custom integration build — teams already on Claude Code absorb it without changing their toolchain. Covers four distinct project types — software, courses, AI tools, service design — which means the discovery logic is not narrowly tuned to one domain and does not require reconfiguration when the project type changes.
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.	The plugin runs exclusively inside Claude Code: if your team moves to a different agent runtime — Cursor, a custom LangChain setup, any other harness — Mycelium stops working and the discovery workflow has to be rebuilt from scratch in whatever replaces it. That is the condition under which teams drop it for a competitor or a homegrown prompt chain. There is no API surface, which means the discovery workflow cannot be triggered programmatically from a CI pipeline, a product management tool, or any external system. Teams that want automated pre-flight checks on tickets or specs have to invoke it manually every time. The project is early-stage with a small contributor base — community reports from the GitHub activity suggest the docs describe intended behavior more than battle-tested edge cases, so teams running it on complex multi-stakeholder briefs are effectively doing their own QA on the questioning logic.

Bottom line

Forall is paid while Mycelium 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 Mycelium?

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

Is Forall better than Mycelium?

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.