hermes acp subprocess over the Agent Client Protocol (ACP) and renders a full chat surface — streaming replies, syntax-highlighted code, one-click diff application, and model switching — right inside VS Code or Cursor. The agent sees your editor state in real time through an in-process MCP server, so it can read and write workspace files, inspect your diagnostics, and act on your cursor position without you copying anything by hand.
This extension is a UI front-end only. Hermes Agent must be installed separately and
hermes must be available on your PATH (or configured via hermes.path) before the extension can connect.Key capabilities
In-editor agent chat
A sidebar conversation with real-time streaming Markdown, syntax-highlighted code blocks (marked + highlight.js, sanitized with DOMPurify), and click-to-insert snippets. No alt-tab required.
Editor Tools Bridge
An in-process MCP server registers
vscode-editor-tools at session start. The agent can query your active file, open tabs, cursor position, selection, visible ranges, live diagnostics, and read/write workspace files.Model picker with live pricing
Every model Hermes exposes is surfaced in a grouped dropdown with the per-token output cost shown inline. Switch provider and model in a single click.
Profile auto-discovery
Hermes profiles are detected from your config and exposed as a one-tap selector. No manual ID juggling.
Permission modes
Choose
manual (default), autoApprove, or denyAll to control how much the agent asks before it touches your system.Diff viewer
Proposed changes render as a real diff. Preview the original versus the proposed version, then apply to disk with a single command.
Multi-session tabs
Run parallel conversations, persisted locally. Rename, delete, or revisit any session from the tab bar.
Context attachment
Carry messages from a prior session into a new chat so the agent starts with background knowledge instead of a blank slate.
CodeLens
“Ask Hermes about this file” and “Explain this” appear above every function and class. Click once to pre-fill a prompt — no copy-pasting required.
Bilingual UI
The interface is fully available in English and 简体中文, following your VS Code display language automatically.
How it works
When you open the Hermes sidebar, the extension spawns ahermes acp subprocess in the background. Communication between the extension and the agent flows over ACP — a lightweight protocol designed for tool-augmented agent sessions. At session start, the extension registers a vscode-editor-tools MCP server that the agent can call to inspect your workspace:
- Active editor — file path, language ID, cursor position, selection, visible ranges, and full file content for files under 500 lines
- Open tabs — labels, language IDs, and dirty/pinned state
- Diagnostics — errors and warnings from your language servers
- File operations — read and write access within the workspace boundary
Requirements
Before installing the extension, confirm you have the following in place.| Requirement | Details |
|---|---|
| VS Code | Version 1.85 or later. The extension also works in Cursor. |
| Hermes Agent | Installed and accessible as hermes on your PATH. Alternatively, set the full path in hermes.path. See hermes-agent.nousresearch.com for install instructions. |
| Node.js + Python | Required for ACP dependencies. Both are auto-installed on first connect if missing. |
agent-client-protocol Python package and installs it automatically via pip if it is not present. If automatic installation fails, run hermes acp --check in a terminal to diagnose and resolve the issue manually.