Grok Build vs Mycelium

Grok Build 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.

Grok Build

Grok Build is xAI's terminal-native coding agent: a full-screen TUI that reads your codebase, edits files, runs shell commands, searches the web, and tracks long-running tasks in a loop. It runs interactively for keyboard-driven sessions, headlessly for scripted pipelines, and embeds into editors via the Agent Client Protocol. The open-source, Apache-2.0 codebase is written in Rust and self-hostable. Where it earns trust is in environments where a GUI agent would require a workaround — shell scripts, CI jobs, editor plugins. Where it starts to show limits is in anything requiring a visual interface, fine-grained permission controls per task, or an API surface you can call programmatically.

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	Grok Build	Mycelium
Pricing	Free	Free
Free trial	No	No
Open source	Yes	Yes
Has API	No	No
Self-hosted option	Yes	Yes
Platforms	macOS, Linux, Windows	Claude Code
Pros	Headless execution mode lets the same agent loop run in CI/CD pipelines without a GUI dependency, so automation you build locally does not require a separate integration layer to work in production. Codebase-aware file editing means the agent reads your project structure before making changes, so edits are scoped to actual files rather than generic code snippets you paste in manually. Shell command execution within the agent loop means multi-step tasks — edit a file, run tests, check output, iterate — happen in a single session rather than requiring you to context-switch between a chat window and your terminal. Agent Client Protocol support lets editors embed the agent directly, so teams using Vim, Neovim, or compatible editors get in-editor AI assistance without routing through a browser-based tool. Apache-2.0 license with self-hosted option means your codebase does not have to leave your infrastructure, which removes the compliance conversation for teams with strict data residency requirements.	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	No public API surface: teams that need to call the agent from a backend service, trigger it via webhook, or integrate it into a non-terminal workflow have no programmatic entry point — the only interfaces described are the TUI, headless CLI, and ACP. Teams with that requirement move to agents that expose a REST or SDK interface. Permission and approval controls before the agent edits files or runs commands are not described in the repo or vendor page — teams that need a human to sign off before changes land in the filesystem will need to build that gate themselves or choose a tool where approval steps are a first-class feature. The project has two commits in the visible repo history at the time of the source page capture, which means the open-source community has precious little track record to evaluate stability, breaking changes, or long-term maintenance — teams running this in production CI carry the risk that the project's public development cadence is still being established.	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

Grok Build and Mycelium are closely matched on pricing model, openness, and API availability — pick by feature set and platform support in the table above.

Frequently asked questions

What is the difference between Grok Build and Mycelium?

Grok Build is Free 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 Grok Build 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.