Swarm Mode: Parallel Multi-Agent Workflows
Swarm Mode is Cosine’s proprietary multi-agent orchestration feature. Where other tools might run subagents occasionally and automatically, Swarm Mode forces the agent to think in parallel — splitting a task into independent streams and delegating each to a dedicated subagent.
What is Swarm Mode?
Section titled “What is Swarm Mode?”In Swarm Mode, the primary agent acts as an orchestrator. After receiving your prompt (typically following a Plan Mode session), it:
- Breaks the task into parallel workstreams.
- Spawns subagents to handle each stream simultaneously.
- Coordinates results and produces a final output.
Each time a subagent starts, the CLI announces it. You can monitor their progress in the Agents panel (Ctrl+3 or Alt+3).
Subagents use the same model as the primary session and have access to the full set of tools — file editing, terminal, search, web, and more.
How Swarm Differs from Normal Subagent Spawning
Section titled “How Swarm Differs from Normal Subagent Spawning”In Normal and Auto modes, the agent will sometimes decide on its own to spawn a subagent when it thinks that would help. This is reactive and unstructured.
Swarm Mode is different:
- It forces the orchestrator to think about parallel delegation upfront.
- It provides an opinionated structure for how the orchestrator will divide and direct the work.
- It’s designed specifically for tasks that are large enough to warrant multiple streams.
Starting a Swarm Session
Section titled “Starting a Swarm Session”There are two ways to enter Swarm Mode:
- From Plan Mode: After the agent finishes a plan, select “Yes, accept and enable Swarm mode” from the confirmation dialog.
- Directly: Press
Shift+Tabto cycle to Swarm mode, then send your prompt.
See the Modes reference for the full list of modes and how to switch between them.
When you first send a prompt in Swarm Mode, you’ll be asked how you want it to run:
| Option | Description |
|---|---|
| Foreground (shared filesystem) | Subagents share your current workspace; watch them work in real time |
| Background (uses worktree) | Creates a git worktree on a new branch; clears the primary timeline and runs in the background |
Practical Example
Section titled “Practical Example”Suppose you want to produce 10 blog posts on different topics. Without Swarm Mode, you’d either write all 10 sequentially or manually open 10 separate agent windows.
With Swarm Mode:
- Prompt the agent: “Research and write 10 blog posts on the following topics: [list].”
- The orchestrator plans how to split the work.
- It spawns subagents — one per topic, or grouped.
- All subagents run in parallel and save their output to your folder.
- You come back to 10 completed drafts.
When to Use Swarm Mode
Section titled “When to Use Swarm Mode”Swarm Mode is most effective when:
- Your task naturally decomposes into independent parallel streams.
- You’re producing multiple similar outputs (multiple blog posts, multiple email drafts, multiple research summaries).
- You’ve just approved a Plan Mode output and want to execute it at maximum speed.
For a single, focused task, Normal or Auto mode is usually more efficient.
Key Takeaways
Section titled “Key Takeaways”- Swarm Mode is a proprietary Cosine feature for structured parallel multi-agent execution.
- The primary agent acts as an orchestrator, delegating to subagents that run simultaneously.
- It differs from auto-spawned subagents in Normal/Auto mode — it’s intentional and structured.
- Combine with Plan Mode for maximum effectiveness on complex tasks.