OpenBar

A spending tab for your coding agent. Local-first cost + bloat receipts for Claude Code and Codex.

🌐 doramirdor.github.io/openbar · 📐 Architecture · 🤝 Contributing · 🔒 Security

  OpenBar  ·  Claude Code

  $1.42 estimated run cost
  213k input tokens  (claude-opus-4-8)
  9.8k output tokens
  18 files touched  +612 -83  5 new
  27 commands run
  5 retries

  Bloat score: 87/100  █████████████████░░░

  Biggest waste:
  Re-read package-lock.json 7 times

  Fix:
  Add lockfiles to your agent ignore rules.

It runs entirely on your machine. No account, no upload, no API key.

Quick start

npm i -g @amirdor/openbar   # installs the `openbar` command
openbar install             # add Claude Code hooks to this project
# ... use Claude Code as usual ...
openbar report              # print the receipt for the last run
openbar summary             # your weekly agent bill across runs
openbar fix                 # turn the biggest wastes into CLAUDE.md rules
openbar share --png         # render a shareable card

No global install? npx @amirdor/openbar install. Using Codex too? add --codex.

How it works

Claude Code / Codex
   │  (lifecycle hooks: SessionStart, PreToolUse, PostToolUse, Stop, …)
   ▼
openbar hook  ──►  .openbar/runs/<session>.jsonl   (append-only event log)
   │
   ▼
analyzer  ──►  transcript/rollout token usage + git diff + waste detectors
   │
   ├─►  receipt (terminal)             openbar report
   ├─►  weekly bill (terminal)         openbar summary
   ├─►  shareable card (SVG/PNG/HTML)  openbar share
   ├─►  agent rules (CLAUDE.md)        openbar fix
   └─►  history (SQLite)               openbar report --history

• install writes hooks into .claude/settings.json (or --global / --local). It's idempotent and reversible (uninstall).
• hook is called by Claude Code at each lifecycle point. It reads the hook JSON from stdin and appends a compact event to the per-session log. It is wrapped to never block or slow down the agent.
• report reconstructs the run: real token usage from the Claude Code transcript, file changes from git diff (or tool events when there's no repo), waste detectors, and a bloat score.

Accurate cost, honestly labeled

Token counts come from the real Claude Code transcript (message.usage), not estimates — including the 5-minute vs 1-hour cache-write split. Cost is computed per-model with Anthropic's cache multipliers (read ×0.10, write-5m ×1.25, write-1h ×2.0).

It's still labeled estimated because pricing for some legacy models is approximate and discount tiers can't be detected. We never show false precision. (Note: on a Claude subscription you don't pay per token — the figure is the API-rate equivalent, a "what this would cost" signal, not an invoice.)

Rates live in a built-in table. To set exact, negotiated, or Batch (50%-off) rates — or price a model OpenBar doesn't know — drop a ~/.openbar/pricing.json:

{ "claude-opus-4-8": { "input": 5, "output": 25 }, "my-model": { "input": 2, "output": 8 } }

Your file wins over the defaults, stays on your machine, and its rates are treated as exact.

One subtlety handled correctly: a single API response is written to the transcript as multiple lines (one per content block) that all repeat the same usage. OpenBar dedupes by request id so tokens aren't counted 3–5× over.

Bloat score

A transparent 0–100 score (higher = more wasteful), capped per dimension so nothing dominates:

| Dimension | Max | |---|---| | files touched | 18 | | lines added | 14 | | repeated reads | 20 | | retries / failures | 16 | | dependency changes | 10 | | generated-file changes | 12 | | big diff for a tiny prompt | 10 |

Waste detectors

Re-read files, lockfile reads, node_modules/dist reads, repeated commands, failing-test loops, dependency changes, edits to generated output, huge file reads, huge tool outputs, edit churn, output-heavy runs, file sprawl, and big-diff-for-small-prompt. Each finding carries a concrete fix.

Codex

Codex has official hooks too, so the same flow works:

npx openbar install --codex   # writes .codex/hooks.json (--global for ~/.codex)

Two Codex specifics OpenBar handles for you:

• Tokens come from Codex's on-disk rollout (~/.codex/sessions/.../rollout-*.jsonl, the token_count lines), normalized so the shared cost math applies. OpenAI pricing is approximate and the receipt says so.
• Trust model: Codex skips a freshly-written command hook until you trust it — run /hooks inside Codex once after installing (or launch with --dangerously-bypass-hook-trust).

openbar fix

Writes a managed block into CLAUDE.md (and AGENTS.md with --all), generated from what actually wasted money in your runs:

<!-- openbar:start -->
## Agent cost rules

- Do not read lockfiles unless explicitly asked. Use the manifest for dependency questions.
- If the same command fails twice for the same reason, stop and explain the blocker.
- Prefer editing existing files over creating new ones.
<!-- openbar:end -->

The block is re-written in place on each run, so it stays current.

Commands

| Command | Description | |---|---| | openbar install [--codex] [--global\|--local] [--print] | Add hooks to Claude Code (or Codex) | | openbar uninstall [--codex] | Remove openbar hooks | | openbar report [session] [--json] [--history] [--transcript path] [--no-save] | Print a receipt | | openbar summary [--days n\|--all] [--json] | Aggregate recent runs (weekly bill) | | openbar share [session] [--png] [--html] [--out file] | Render a shareable card | | openbar fix [session] [--all] [--target file] [--print] | Write rules into CLAUDE.md / AGENTS.md |

Requirements

• Node ≥ 22.5 (uses the built-in node:sqlite for history; history degrades gracefully if unavailable).
• Zero required runtime dependencies. PNG export uses the optional @resvg/resvg-js; without it, share --png writes a browser-based PNG exporter instead.

Development

npm install      # builds via the prepare script
npm run build
npm test         # end-to-end smoke tests (Claude Code + Codex) against the compiled binary

See CONTRIBUTING.md for the project layout and how to add a detector, and docs/ARCHITECTURE.md for the data flow.

Troubleshooting

Hooks are silent by design (agents can inject hook stdout into the model). If a run isn't showing up, set OPENBAR_DEBUG=1 and check .openbar/openbar.log. Confirm the hooks are registered with openbar install --print. On Codex, remember to trust the hook via /hooks after installing.

Status

V0 — Claude Code + Codex, fully local. Done: receipts, accurate per-model cost, bloat score, waste detectors, fix rules, SVG/PNG/HTML share cards, local history + weekly summary.

Deliberately deferred until the receipt is getting shared (per the original plan): cloud sync, team dashboard, PR comments, budget alerts, and billing. None of that is required to get value from the receipt.

License

MIT