Assumer vs OpenCode
An honest, side-by-side look at Assumer and OpenCode by Anomaly (anomalyco): where each one runs, which models it uses, how it handles tools and permissions, and what it costs.
Last checked October 2026. Facts about OpenCode come from its official docs and pricing pages, linked below.
At a glance
| Feature | Assumer | OpenCode |
|---|---|---|
| Made by | 4Born Solutions | Anomaly (anomalyco) |
| Where it runs | Terminal, Desktop app, Web | Terminal, Desktop app, IDE, Web |
| Open source | Built on OpenCode (MIT) | Yes (MIT) |
| Models | Models run through the Assumer service; sign-in required (assumer login, device flow). |
Provider-agnostic: 75+ providers via AI SDK and Models.dev, plus OpenCode Zen (curated models) and OpenCode Go (subscription). |
| Bring your own API key | No | Yes |
| Local models | No | Yes |
| MCP support | Yes | Yes |
| Plan mode | Yes | Yes |
| Subagents | Yes | Yes |
| Rules file | Assumer.md (AGENTS.md and CLAUDE.md compatible) | AGENTS.md |
| Windows | Yes | Partial |
| Pricing | Free; paid from $20/mo | Free; paid from $10/mo |
Where each one shines
Choose Assumer if you want
- Spec-driven development built in: constitution, specify, plan, tasks, implement.
- Meetings: turns a meeting transcript into a development plan.
-
Many surfaces from one install: terminal TUI/CLI, headless server (
assumer serve), web UI (assumer web), ACP for editors such as Zed, plus a desktop app.
Choose OpenCode if you want
- MIT-licensed and provider-agnostic, with documented local model setups (Ollama, LM Studio, llama.cpp).
- Build and Plan primary agents plus General and Explore subagents, with custom agents in Markdown or JSON.
- Local and remote MCP servers with automatic OAuth handling.
Trade-offs to know
Assumer
- Requires sign-in; models run through the Assumer service rather than your own provider keys.
- Desktop downloads, the curl installer and Homebrew are coming soon; install today is via npm.
OpenCode
- On Windows the docs recommend WSL for best performance and full compatibility.
- Desktop app is labelled beta.
Pricing
Assumer
Free
Placeholder pricing
$0
Pro
Placeholder pricing
$20/mo
Max
Placeholder pricing
$100/mo
Team
Placeholder pricing
$40/user/mo
Enterprise
Placeholder pricing
Custom
OpenCode
Open source
Bring your own provider keys
$0
Go
Low-cost access to open-source coding models
$10/mo
Go Plus
Higher limits
$40/mo
Zen
Curated, tested models; per-model prices not verified
Pay as you go
Frequently asked questions
Is Assumer a good alternative to OpenCode?
Yes, if you want an AI coding agent for the terminal and desktop with plan and build agents, MCP servers, granular permissions, spec-driven development and meeting-to-plan workflows. If the OpenCode strengths listed on this page matter most to your team, OpenCode may be the better fit.
How much do Assumer and OpenCode cost?
Assumer: Free; paid from $20/mo. OpenCode: Free; paid from $10/mo. Prices change often, so check each pricing page before you buy.
Can I use my AGENTS.md rules with Assumer?
Yes. Assumer reads Assumer.md rules files and is compatible with AGENTS.md and CLAUDE.md. OpenCode uses AGENTS.md.
Do Assumer and OpenCode support MCP?
Assumer supports local and remote MCP servers. OpenCode: yes.
Try Assumer alongside OpenCode
Install the CLI in one command and run it on a real task in your own repository.
npm i -g @4born-solutions/assumer