Codestral Agent
A coding assistant and multi-file agent for VSCodium and Visual Studio Code, powered by Mistral Codestral.
Overview
Codestral Agent adds an AI coding assistant directly to the VS Code activity bar. It can chat with your project, inspect the active file, read workspace context, prepare multi-file patches, show diffs, apply changes, run validations, inspect errors, and iterate on fixes.
It is designed as an open, bring-your-own-key alternative for developers who want a practical coding agent inside VSCodium or Visual Studio Code.
Marketplace
Extension ID:
CodestralAgent.codestral-ai
Marketplace page:
https://marketplace.visualstudio.com/items?itemName=CodestralAgent.codestral-ai
Source code:
https://github.com/AnARCHIS12/Codestral-Agent
Issues and support:
https://github.com/AnARCHIS12/Codestral-Agent/issues
Features
- Activity bar panel for Codestral Agent.
- Local chat with conversation history.
- Multi-file agent mode for creating, editing, and deleting workspace files.
- Visible execution plan in the sidebar.
- Diff preview before applying changes.
- Controlled apply flow and revert for the last agent patch.
- Project validation with test, build, typecheck, lint, and static web checks when available.
- Agent correction loop after validation failures.
- Active editor detection and workspace context reading.
- Local project index and memory stored in
.codestral/.
- Mistral/Codestral model selector based on the models available for your API key.
- Token usage counter for chat, router, and agent requests.
- Interface and response language settings.
- Optional one-time privilege elevation request through the terminal when a command fails because of permissions.
Current Version
0.1.7
Main changes in this version:
- Improved validation for static HTML/CSS/JavaScript projects.
- The agent no longer tries to repair
package.json when the test script only prints an echo message or asks the user to open a browser.
- Simple web projects use a static HTML/CSS/JS smoke check and JavaScript syntax validation when useful.
- API key persistence was improved with a local fallback for environments where SecretStorage is not restored correctly.
- The API field can pre-fill the saved key.
- Token usage is updated after chat, router, and agent calls.
- The active model is displayed in compact form with a full-name tooltip.
- The Agent button can launch an agent task directly from the sidebar input.
Installation
Install from the Visual Studio Marketplace when available:
https://marketplace.visualstudio.com/items?itemName=CodestralAgent.codestral-ai
Or install the local VSIX package:
- Open the Extensions view in VSCodium or VS Code.
- Open the
... menu.
- Select
Install from VSIX....
- Choose
codestral-ai-0.1.7.vsix.
- Reload the window with
Developer: Reload Window.
API Key Setup
- Open the Codestral icon in the left activity bar.
- Click
API.
- Choose
Open Mistral Console or Enter API Key.
- Click
Mod to select an available model.
Mistral Codestral console:
https://console.mistral.ai/codestral
Commands
| Command |
Description |
Codestral: Set API Key |
Store or update your API key |
Codestral: Show Available Models |
Fetch models available for your key |
Codestral: Select Model |
Switch the active Mistral/Codestral model |
Codestral: Settings |
Open the Codestral settings menu |
Codestral: Complete Code |
Generate code at the cursor position |
Codestral: Chat |
Start a chat request with project context |
Codestral: Explain Selection |
Explain the selected code or active file |
Codestral: Fix Selection |
Suggest a fix for the selected code |
Codestral: Generate Tests |
Generate tests for the selection or active file |
Codestral: Review File |
Review the active file and list risks |
Codestral: Agent Task |
Run the multi-file agent workflow |
Codestral: Revert Last Agent Patch |
Restore files from the last agent backup |
Codestral: Rebuild Workspace Index |
Rebuild the local project index |
Codestral: Start Dev Server |
Start a detected development server command |
Codestral: Stop Dev Server |
Stop the current development server |
Codestral: Restart Dev Server |
Restart the development server |
Codestral: Run Tests and Diagnose |
Run validation and ask Codestral for diagnostics |
Local Data
Codestral Agent stores data locally in your editor environment:
- API key through VS Code SecretStorage, with a local fallback for some VSCodium/Flatpak setups.
- Conversation history.
- Selected model.
- Interface and response language preferences.
- Last token usage.
- Agent run history and project memory under
.codestral/ inside the workspace.
The API key is sent only to the Mistral/Codestral API when you use the extension.
Security
Codestral Agent works inside the opened workspace. It does not run sudo automatically. If a command fails because of permissions, the extension can ask for confirmation and open a terminal where you remain in control.
Never commit a real API key to Git.
Development
From the extension folder:
npm install
npm run compile
npm run package:vsix
The generated package is:
codestral-ai-0.1.7.vsix
License
MIT License. Copyright (c) 2026 CodestralAgent.
