A standalone Windows app that shows how much of the context window each of your Claude sessions has used — read straight from the session files Claude already writes to disk.
Claude Code has a built-in context counter; the Claude desktop app doesn't surface one the same way. This fills that gap, showing every session's token usage as a sortable list with a colour-coded percentage bar.
Session titles and project names are blacked out in this screenshot only — the app shows them normally.
A Cowork session can run in one of two places, and it makes all the difference:
| Cowork session type | Runs on | Readable by this app? |
|---|---|---|
| Local (cloud disabled) | your PC | ✅ Yes — exact per-turn tokens |
Cloud (claude.ai/cowork/cse_…, tagged "Cloud" in the UI) |
Anthropic's servers | ❌ No |
Cloud sessions execute remotely and write no transcript to your machine, so there is nothing on disk to measure. Only the session's space memory files sync down — no messages, no token counts.
So: turn cloud off for Cowork sessions you want to track. A local session
writes a normal transcript with per-turn usage data, and this app reads it
exactly and reliably — no workarounds involved.
This was verified the hard way. Every other avenue for cloud sessions was checked and is a genuine dead end: the VM disk (scanned twice, holds no token values at all), the app's local web storage, any local port, and Claude Desktop's own accessibility tree — which exposes a context readout on the Claude Code surface but not on Cowork.
- All your sessions in one list — title, project, source (Code / Cowork), model, last activity, tokens used, and % of the context window (green < 60%, amber 60–80%, red > 80%)
- Live sessions are badged, and Auto-refresh (5s) lets you watch a running session's context climb while you work
- Double-click any session for the full token breakdown (input / cache read / cache creation / output) and its context growth history
- Surface-aware window sizing (new in v2.2) — Cowork runs a smaller context window than other surfaces, so the percentage is now meaningful instead of running past 100% (see below)
- Daemon/background jobs are recognised and shown with their real name
- Search, hide-empty and hide-archived filters, sortable columns
- Resilient across restarts/updates: keeps a small private snapshot of your last-seen sessions, so opening the meter right after a reboot or a Claude Desktop update shows them immediately (flagged "showing last known") instead of an empty list, then refreshes to live data
- Safe by design: only ever reads your Claude session files (shared-read
mode, never locks or modifies them), and no network access. The one thing it
writes is its own cache at
%LOCALAPPDATA%\CoworkContextMeter\cowork-cache.json
- Download
CoworkContextMeter-portable.zipfrom Releases and extract it anywhere on a Windows 10/11 PC. - Double-click
CoworkContextMeter.exe. No installer, no admin rights, nothing else to download — it uses the .NET Framework already in Windows. - If SmartScreen warns about an unsigned download, click More info → Run anyway.
- List looks empty? Run
Diagnose.exe— it prints which Claude data folders exist on that machine and what was found in them.
Auto-compaction fires at a fixed reserve below the window, not a percentage:
compaction point = window − 33,000
(20,000 output reserve + 13,000 headroom)
Verified three independent ways: the Claude Code CLI bundle, live client
telemetry (1,000,000 → 967,000 and 967,000 → 934,000), and nine measured
compaction events on a 200k model (which fired at 167,287–171,567).
Cowork gets a smaller window than other surfaces. The CLI carries a per-model table keyed by surface:
| Model | Cowork surface | Other surfaces |
|---|---|---|
claude-sonnet-5 |
500,000 | 967,000 |
So a Cowork sonnet-5 session compacts near 467,000, not 967,000. Before
v2.2 the app assumed 200k for these sessions and displayed over 100% once they
passed 200,000 tokens. (The 500,000 figure comes from the CLI bundle and is
not independently confirmed; the window − 33,000 rule is.)
Practical takeaway: the model picker is the real lever — a 1M-class model gives roughly six times the runway of a 200k one, with nothing to install and nothing to break.
Claude stores each session as a JSONL transcript, plus (for desktop sessions) a small state file. The app resolves these per Windows user — no fixed paths:
| What | Where it lives |
|---|---|
| Session transcripts | %USERPROFILE%\.claude\projects\ |
| Background/daemon jobs | %USERPROFILE%\.claude\jobs\ |
| Cowork sessions (local) | …\Claude\local-agent-mode-sessions\ |
Desktop session state (title, model, [1m]) |
…\Claude\claude-code-sessions\ |
A session's current context is the token usage on its latest assistant
turn: input + cache_read + cache_creation + output. After a compaction the
number drops automatically.
The packaged-app trap (important if you're modifying this). Claude Desktop
is an MSIX-packaged app, so its data is not in the real %APPDATA%\Claude
— it lives under:
%LOCALAPPDATA%\Packages\Claude_<publisherid>\LocalCache\Roaming\Claude\
The app globs for that package folder. This detail caused several false
diagnoses during development: a shell launched by Claude resolves paths
into the container automatically, so everything looks fine from there, while
the same program launched from Explorer sees the real, empty %APPDATA%.
Always test by launching from Explorer, not from a Claude-spawned shell.
If the list suddenly shows no Cowork sessions, check which build is running
before suspecting anything else — the window title carries the version and
build time (Cowork Context Meter v2.2 - updated …). A stale copy launched by
an old Startup shortcut will silently report zero Cowork sessions.
Under the hood it also handles Cowork's 270–470-character sandbox paths, which exceed the Windows path limit that is still off by default — no registry changes needed.
No SDK needed — it compiles with the C# compiler that ships inside Windows:
powershell -ExecutionPolicy Bypass -File .\build.ps1src/—Scanner.cs(core logic),App.cs(WinForms UI),TestScanner.cs(test harness),Diagnose.cs(the diagnostic shipped in the portable zip)- The release zip is the prebuilt package: both exes plus its own source and build script.
The source is deliberately C# 5 only, because that's what the built-in
.NET Framework compiler (csc.exe) understands.
Found a bug? Everyone is welcome to fix it — open an issue describing what went wrong, or send a pull request. Small fixes, big fixes, all appreciated.
One request: please don't submit changes that read another application's browser cache or other private storage to extract session data. An earlier unreleased build did exactly that to reach cloud Cowork sessions; antivirus correctly flagged it as infostealer-shaped behaviour, and it was dropped. If cloud Cowork usage becomes available through a supported interface, that would be a very welcome contribution.
Originally built by Claude (Fable 5), June 2026. Compatibility work from v1.1 onward — storage-layout fixes, the MSIX container discovery, and the local-vs-cloud investigation behind the note at the top — by Claude (Opus 4.8 / Opus 5).