Assumer vs Devin Desktop (formerly Windsurf)
An honest, side-by-side look at Assumer and Devin Desktop (formerly Windsurf) by Cognition: where each one runs, which models it uses, how it handles tools and permissions, and what it costs.
Last checked October 2026. Facts about Devin Desktop (formerly Windsurf) come from its official docs and pricing pages, linked below.
At a glance
| Feature | Assumer | Devin Desktop (formerly Windsurf) |
|---|---|---|
| Made by | 4Born Solutions | Cognition |
| Where it runs | Terminal, Desktop app, Web | IDE, Desktop app, Terminal, Web |
| Open source | Built on OpenCode (MIT) | No (proprietary) |
| Models | Models run through the Assumer service; sign-in required (assumer login, device flow). |
Frontier and open-source models on paid plans; ACP lets agents such as Codex, Claude Agent and OpenCode run inside the editor. |
| Bring your own API key | No | Partial |
| Local models | No | Not verified |
| MCP support | Yes | Yes |
| Plan mode | Yes | Not verified |
| Subagents | Yes | Yes |
| Rules file | Assumer.md (AGENTS.md and CLAUDE.md compatible) | .devin/rules/ (also AGENTS.md; legacy .windsurfrules and .windsurf/rules/) |
| Windows | Yes | Yes |
| Pricing | Free; paid from $20/mo | Free; paid from $20/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 Devin Desktop (formerly Windsurf) if you want
- Full IDE backward-compatible with Windsurf and VS Code extensions and keybindings.
- Agent Command Center manages local and cloud agents in one Kanban view.
- Open to other agents through the Agent Client Protocol (ACP).
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.
Devin Desktop (formerly Windsurf)
- Recent rename and agent transition (Cascade to Devin Local) may mean docs and workflows are still settling.
- Free tier has limited model availability and a light quota.
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
Devin Desktop (formerly Windsurf)
Free
Light quota, limited models, unlimited Tab
$0
Pro
Devin Desktop + Devin Cloud
$20/mo
Max
Significantly higher quotas
$200/mo
Teams
Up to 200 users
$80/mo + $40/dev seat/mo
Enterprise
SSO, VPC deployment option
Custom
Frequently asked questions
Is Assumer a good alternative to Devin Desktop (formerly Windsurf)?
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 Devin Desktop (formerly Windsurf) strengths listed on this page matter most to your team, Devin Desktop (formerly Windsurf) may be the better fit.
How much do Assumer and Devin Desktop (formerly Windsurf) cost?
Assumer: Free; paid from $20/mo. Devin Desktop (formerly Windsurf): Free; paid from $20/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. Devin Desktop (formerly Windsurf) uses .devin/rules/ (also AGENTS.md; legacy .windsurfrules and .windsurf/rules/).
Do Assumer and Devin Desktop (formerly Windsurf) support MCP?
Assumer supports local and remote MCP servers. Devin Desktop (formerly Windsurf): yes.
Try Assumer alongside Devin Desktop (formerly Windsurf)
Install the CLI in one command and run it on a real task in your own repository.
npm i -g @4born-solutions/assumer