Codex Claude Context Monitor

Codex-Claude-Monitor is a VS Code extension that tracks context usage for the current Codex or Claude Code session right in the status bar.

The extension reads local session files for both Codex and Claude Code, then displays whichever tool was active most recently. It makes no network requests — everything is computed from files already on your machine.

Features

• Unified status bar item for both Codex and Claude Code. The provider whose session file was updated most recently wins, so you never have to switch anything manually.
• Color-coded warnings that adapt to your theme as context fills up:
  • 🟢 green below 50%
  • 🟡 yellow at 50–79%
  • 🔴 red at 80% and above
• Minimal, icon-based status bar showing the active provider, context percentage, and (for Codex) compact 5h/weekly usage via codicon icons, so it stays compact and language-neutral.
• Detailed hover tooltip with exact token counts, the friendly model name, Claude token composition and cache-hit rate, and 5-hour / weekly rate-limit usage for both providers with the reset time and a relative countdown.
• Workspace-aware filtering — only sessions whose working directory lives inside your current VS Code workspace are counted, so CLI sessions from other projects are ignored.
• Click to refresh immediately, plus automatic refresh on a configurable interval.
• Handoff above 50% — when context exceeds 50%, a Handoff entry appears beside the status bar. Click it to copy a compact continuation prompt (context %, session file, branch, plus a minimal Task/Done/Next/Constraints skeleton) to the clipboard, so a fresh session can pick up where this one left off.

Display

The status bar shows compact text such as:

Codex $(comment) 13% · $(history) 45% · $(calendar) 23%
Claude $(comment) 18% · $(history) 25% · $(calendar) 8%

• The leading label is the active provider, followed by $(comment) (a speech-bubble icon marking the current session) and the context usage percentage.
• Both providers append compact rate-limit segments using codicon icons: $(history) is the 5-hour window and $(calendar) is the weekly window. Codex reads them from its session files. For Claude they are probed by periodically running claude -p "/usage" in the background (every 15 minutes by default, configurable via agentTokenStatus.claudeUsageProbeIntervalMs; set 0 to disable). Until the first successful probe, the Claude segments are omitted. Icons replace letter abbreviations (5h/w) so the bar reads the same in any language.
• The friendly model name (e.g. Opus 4.8) and rate-limit reset times (with a relative countdown) stay in the hover tooltip.
• The item color reflects context-usage severity (green / yellow / red, see above).
• Codex percentages come from input_tokens / model_context_window for the latest request.
• Claude Code percentages come from input_tokens + cache_read_input_tokens + cache_creation_input_tokens, divided by the inferred context window.

Hover the status bar item to see full detail. Both providers show 5-hour and weekly usage with the reset time and how long remains; Claude adds the friendly model name plus token composition and cache-hit rate:

Codex: ctx 136k / 258k (53%)
5h usage: 21% · Reset at 14:32 (in 2h 32m)
Weekly usage: 10% · Reset at 6/8 09:24 (in 4d 21h)

Claude: ctx 36k / 1m (18%)
Model: Opus 4.8 (1M context)
Tokens: input 2 · cache read 36k · cache create 411
Cache hit: 100%
5h usage: 32% · Reset at 16:39 (in 38m)
Weekly usage: 10% · Reset at 7/14 00:59 (in 8h 58m)

Once a reset time has passed (stale session data), the countdown is omitted and only the absolute time remains.

Click the status bar item to refresh immediately without opening a notification. Detailed usage always stays in the hover tooltip.

Handoff (context above 50%)

When context usage exceeds 50%, a second status bar item appears just beside the main one:

$(export) Handoff

Click it to copy a paste-ready handoff (continuation) prompt to the clipboard. It keeps only what a fresh session can't infer — why you're handing off and where to continue — and trusts the model to fill in the rest:

Continue this work in a fresh context (previous session at 85%).

Session: /home/u/.claude/projects/proj/abc.jsonl
Branch: main

Task: <one-line goal>
Done: <completed work — do not redo>
Next: <where it stopped + immediate next step>
Constraints: <locked decisions / scope>

Paste it into a fresh (or the current) session and the Claude there fills in each placeholder from the session history. Surfacing the suffix is the only automatic behavior; generating and copying the prompt is strictly user-triggered — nothing is copied or sent until you click.

Installation

From the Marketplace. Search for "Codex-Claude-Monitor" in the Extensions view, or run this in the Command Palette (Ctrl/Cmd+Shift+P):

ext install jialei2005.codex-claude-ctx-monitor

From source (development). Link this directory into the VS Code extensions directory:

ln -s /path/to/codex-claude-monitor ~/.vscode/extensions/codex-claude-monitor

Then reload the window via the Command Palette (Developer: Reload Window). After reload, Codex or Claude Code context usage appears on the right side of the status bar. You can also trigger commands manually at any time:

Codex-Claude-Monitor: Refresh
Codex-Claude-Monitor: Handoff

Refresh re-reads usage immediately. Handoff copies the handoff prompt to the clipboard whether or not context has exceeded 50%, so you can generate one on demand.

Configuration

Setting	Default	Description
agentTokenStatus.sessionsRoot	~/.codex/sessions	Optional absolute path to the Codex sessions directory. Leave empty to use the default.
agentTokenStatus.claudeRoot	~/.claude	Optional absolute path to the Claude Code home directory. Leave empty to use the default.
agentTokenStatus.refreshIntervalMs	10000	How often (in milliseconds, minimum 1000) to re-read usage from local session files.
agentTokenStatus.claudeUsageProbeIntervalMs	900000	How often to probe Claude subscription usage by running claude -p "/usage". Minimum 300000; set 0 to disable.
agentTokenStatus.claudeCliPath	""	Optional absolute path to the claude CLI. Leave empty to auto-detect (~/.local/bin, Homebrew, /usr/local/bin, then PATH; on Windows: ~\.local\bin\claude.exe, %APPDATA%\npm\claude.cmd, then PATH).

Changing any of these settings refreshes the status bar and restarts the refresh timer immediately.

How It Works

Data flows from local session JSONL files → provider parsers (with workspace filtering) → most recently active provider → status bar.

Codex. The extension recursively scans ~/.codex/sessions for rollout-*.jsonl, picks the newest file by modification time, and reads the last token_count event. Files are matched to your workspace by reading each candidate's session_meta.payload.cwd.

~/.codex/sessions

Claude Code. The extension recursively scans ~/.claude/projects for .jsonl files, tries the newest ones (skipping files without an assistant entry, such as usage-probe sessions), and reads the last type: "assistant" entry that carries message.usage. The context window is inferred from the model name (model names containing 1m or fable, or claude-opus-4-7 / claude-opus-4-8, use 1M; everything else uses 200k). If the observed context tokens already exceed the inferred window, the window upgrades to 1M so the percentage stays meaningful for unlisted big-window models. Workspace filtering uses Claude's munged directory names, so files don't even need to be open.

~/.claude/projects

Sessions whose working directory is outside the current workspace are ignored. An empty window disables workspace filtering and shows the latest global session.

Privacy

The extension only reads local session files. It does not make network requests, upload data, or collect telemetry.