Devin Desktop - The local editor application, formerly Windsurf: an IDE with an agent, now part of Cognition's Devin ecosystem.
Surface - The environment where work runs: the local IDE, Devin Local, Devin Cloud, Cascade or a third-party ACP agent. Each has its own context, permissions and security boundary.
Tab - A prediction of the next edit right in the editor: continue the code or jump to the next place to change.
Command - A pointed change to the selected fragment from a short instruction (Cmd/Ctrl+I), without a full agentic loop.
Devin Local - The main agent on your machine: a loop with tools (read, write, exec, fetch, MCP) under explicit permissions and a system sandbox.
Agent mode and permission mode - Different axes: the agent mode sets the kind of work, the permission mode how freely the agent acts without approval.
Permission rules - Deny - ask - allow rules for the agent's tools: what is forbidden, what asks for approval, what runs automatically.
Sandbox - The system boundary for running commands: what the process may read, write and connect to over the network - protection by OS means, not an instruction in the prompt.
Worktree sessions - Isolated git worktrees for parallel tasks: each agent edits its own diff without disturbing the others.
Subagents - Separate roles with their own context and tool set, launched foreground or background for a specific part of the work.
AGENTS.md - A short durable contract of the project for the agent: a portable file with the repository's rules and context.
Rules and Skills - Durable instructions (always-on, manual, by glob) and on-demand skill procedures with steps and assets.
MCP - Connecting external tools and data over the Model Context Protocol in a separate config with minimal grants.
Hooks - Deterministic, verifiable policy around tool calls: allow, change or block an action and leave a trace.
Agent Command Center - A single queue of agent decisions: what is waiting for human attention, across all surfaces at once.
Spaces - A shared task context, shared between surfaces and the people working on it.
Devin Cloud - A task in a separate cloud VM with a long horizon, its own setup, secrets and network policy; the result comes back as a branch and a pull request.
ACP - The Agent Client Protocol - a shared protocol for connecting third-party agents; a shared protocol does not mean a shared trust policy.
Cascade - The Windsurf-era agent with code/chat modes, checkpoints, memories and workflows; in Devin Desktop it remains for support and migration.
Restricted Mode - A mode where agents must not run: when autonomy is unacceptable and work is done by hand only.