Codex Context Bridge

Codex Context Bridge is a local VS Code extension that restores Ctrl+L and Ctrl+Shift+L context attachment for editors that are not backed by a normal file: URI.

It exists for cases like:

• notebook cells opened as vscode-notebook-cell
• VS Code profile files such as keybindings.json opened as vscode-userdata
• other virtual editors where the stock chatgpt.addToThread command silently does nothing

Why This Exists

The OpenAI Codex VS Code extension handles selected-line attachment through chatgpt.addToThread, but that path only works for file-backed editors.

This bridge keeps the default Codex behavior whenever it can:

• normal files still go through the native OpenAI commands
• non-file editors fall back to a temporary snapshot file
• full-document attach stays visually minimal
• partial selection attach keeps enough cell or line metadata to stay useful

Visual Examples

Selection attach from a notebook cell or VS Code profile JSON:

Full-document attach from a non-file editor:

Behavior

Ctrl+L

• For file: editors, delegates to the native chatgpt.addToThread command.
• For non-file editors, creates a temporary snapshot such as keybindings.json [Lines 12-18].md or svd_practice.ipynb [Cell 8, Line 1].md.

Ctrl+Shift+L

• For file: editors, delegates to the native chatgpt.addFileToThread command.
• For non-file editors, attaches the whole document through a temporary snapshot that uses only the source filename, for example svd_practice.ipynb.

Snapshot Lifecycle

The bridge writes temporary files only for non-file editors.

• Snapshots live under %USERPROFILE%\.codex-context-bridge\snapshots
• Each VS Code session gets its own snapshot folder
• Repeated attachments for the same source and selection reuse the same snapshot path
• Reattaching updates the snapshot content in place instead of creating numbered duplicates
• The current session folder is deleted when the extension session ends
• Session folders older than one day are removed on startup
• Legacy loose files under the snapshot root are removed on startup

This keeps the behavior simple:

• selected snippets remain readable in Codex
• whole-document chips stay clean
• snapshot files do not accumulate indefinitely under normal use

Repository Layout

• package.json: local extension manifest
• extension.js: command bridge and session-scoped snapshot handling
• lib/snapshot.js: snapshot naming and content rules
• scripts/install.ps1: installs the extension and updates keybindings
• scripts/smoke-test.ps1: validates extension registration and keybinding wiring
• tests/snapshot.test.js: Node-based unit tests for snapshot formatting
• docs/assets/: README illustrations

Install Or Reapply

Run this after a Codex extension update or when reinstalling the bridge:

powershell -ExecutionPolicy Bypass -File .\scripts\install.ps1

Then reload VS Code with Developer: Reload Window.

Keybindings

The installer writes these bindings:

• Ctrl+L -> codexContextBridge.addSelectionToThread
• Ctrl+Shift+L -> codexContextBridge.addActiveDocumentToThread

Notes

• README.md, .py, and other normal files still use the native Codex flow. That is why they can show the cleaner built-in chip from the OpenAI extension.
• The bridge only activates when the native extension cannot attach context because the active editor is not file-backed.
• This repository is a local workaround, not an official OpenAI project.

Test Commands

node .\tests\snapshot.test.js
powershell -ExecutionPolicy Bypass -File .\scripts\smoke-test.ps1