Live subscription limits, resets and budget checks for coding agents over MCP.
Your coding agents check their Claude and Codex limits before they start a job.
headroomd reads the 5-hour and weekly limits your subscriptions report and answers go, wait or reroute, over the CLI or MCP.
npm install -g headroomd # or: brew install apertur3/tap/headroom
headroom setup
headroom can claude-fable --owner me && echo go
Then install the Claude Code plugin (requires headroomd above):
claude plugin marketplace add Apertur3/headroom
claude plugin install headroom@headroom
macOS, Linux, Windows (experimental). No telemetry. Zero runtime dependencies.
Not a cost tracker: ccusage estimates spend from local logs; headroomd reads the limit the vendor enforces. They work side by side.
Unofficial; some readers use undocumented vendor endpoints with your own login. See Vendor endpoints and your accounts.
Not related to headroomlabs-ai/headroom, the context-compression project.
Node 22.13 or newer. The npm package is headroomd; the Homebrew formula is
apertur3/tap/headroom. Both install the headroom command.
npm install -g headroomd
# or, on macOS and Linux: brew install apertur3/tap/headroom
# finds your logins, runs the doctor, asks before each change
headroom setup
# one block per account: percent used, reset time and pace state per window
headroom
For Claude Code, install the plugin after installing headroomd with npm or Homebrew:
claude plugin marketplace add Apertur3/headroom
claude plugin install headroom@headroom
It bundles the Headroom skill, the MCP server registration and a quota line on every prompt.
Using it alongside headroom hook install does not print the quota line twice.
See Claude Code plugin for requirements and uninstall commands.
Already running Claude Code or another agent? Copy skills/headroom/SKILL.md into its skills directory and say "set up headroom".
Without the plugin, headroom setup offers to register the MCP server for your default Claude Code
profile. To register it by hand, or in another profile:
claude mcp add --scope user headroom -- headroom mcp
CLAUDE_CONFIG_DIR=~/.claude2 claude mcp add --scope user headroom -- headroom mcp
Agents without MCP, Codex for example, call the CLI. Then give your agents the instructions in For agents. The MCP tools and example calls are in docs/mcp-and-agents.md.
The three commands above are the short path. Discovery on its own:
headroom accounts discover # finds Claude, Codex, Antigravity, Grok and Kimi logins
On macOS and Linux, brew install apertur3/tap/headroom installs the same package and adds a
brew services start headroom service.
By hand, the same steps are one command:
headroom setup # discovery, doctor, service, MCP registration -- asks before each change
Run headroom notify configure to choose notification channels, a preset and overrides. Run
headroom update only when you choose to install a newer package; headroom uninstall reverses
setup, and headroom completion <bash|zsh|fish|pwsh> prints a shell completion script.
accounts discover prints what it wrote (Wrote ~/.headroom/accounts.toml (4 accounts). Next: headroom doctor) and, the first time, seeds ~/.headroom/policy.toml and routing.toml from examples/ so
headroom can <class> --owner <your-agent-name> works immediately with the example action classes (claude-fable, codex-build,
gemini-bulk) -- edit routing.toml to match your accounts.
Keep an optional second profile that is deliberately logged out without polling it: add
enabled = false to its [[accounts]] block, or run headroom accounts disable <name>.
It remains configured and can be restored with headroom accounts enable <name>.
Full walkthrough, including what each step grants and why: docs/quickstart.md.
status/doctor check the npm registry at most once a day (a plain GET of the headroomd
version, no account data) and print a one-line notice when a newer headroomd is out; run
headroom update (never automatic) to install it. Set update_check = false in
~/.headroom/policy.toml to turn the check off -- see
Staying up to date.
Paste this into the CLAUDE.md or AGENTS.md your agents read, and replace the placeholders with
your own action classes, meters and agent name. The agent then checks Headroom before it dispatches
work, instead of asking you.
## Usage limits (Headroom)
Check Headroom before you start work on a subscription. Do not ask me about usage or reset times.
- `headroom can <class> --owner <your-name>`: exit 0 means go, exit 2 means no. Any other exit
is an error: treat it as no. Classes are the `[consumes]` entries in `~/.headroom/routing.toml`.
- On no, try the next class in your fallback list. If none has room, run
`headroom wait --meter <meter> --until-reset --max 6h` (exit 3 means it timed out), then run
`headroom can` again before you start anything.
- Start a job with
`headroom run --meter <meter> --need <window>:<points> --owner <your-name> -- <command>`,
for example `--need 5h:10` for 10 percent of the 5-hour window. It reserves the points, runs
the command and releases them when it exits. Exit 2 means refused; otherwise it returns the
command's own exit code.
- UNKNOWN means there is no trustworthy reading. Treat it as no. Never pass `--allow-unknown`
unless I ask for it.
- For the full picture, read `headroom --json`, not the human view.
- In Claude Code with the Headroom MCP server, `quota_can` answers the same question as
`headroom can`.
To put live quota in front of the agent on every turn, run headroom hook install --agent claude
(or answer yes in headroom setup). Each Claude Code prompt then carries one line the daemon wrote at
its last poll, with its age, for about 60 tokens per turn; headroom line prints the same line for any
agent. Claude Code on macOS and Linux only for now; Windows, Codex and Gemini hooks are not supported yet.
A plain can is advisory. A reservation tells other agents that use Headroom the points are taken;
it does not limit what the job itself spends, and it cannot stop tools that do not use Headroom.
The longer version, with pace states, leases and reserves, is
skills/headroom/SKILL.md.
| 7 sources read |
3 OSes tested in CI |
1 local daemon, one call per decision |
0 telemetry (one opt-out update check) |
| Platform | Status |
|---|---|
| macOS | The primary platform: daily use on one machine, plus CI. Antigravity needs macOS 14 or later |
| Linux | CI on Ubuntu; cold install also checked by hand on ARM64 |
| Windows | Experimental. Tests run in CI. On Windows 11, headroom install-service registers a "Headroom Daemon" task that starts immediately and serves a per-user named pipe whose name is a hash only. headroom uninstall --home asks the running daemon to shut down over that pipe, removes the task and the home, and exits 0. After an in-place upgrade, headroom install-service restarts the daemon onto the new version, except a daemon started by 0.2.6 or older, which has no shutdown request and must be stopped by hand once (end node.exe in Task Manager). Verified on Windows 11: MCP registration (claude mcp add --scope user headroom -- headroom mcp shows Connected) and a real Claude login read (fresh on the first poll). Not verified on Windows: a slow stop (the 27 second wait is covered by unit tests only) and start at logon and across reboots. Full detail below |
| Antigravity | Experimental. Depends on a private local endpoint that the vendor can change |
| Grok | Experimental. Reads the Grok CLI's undocumented chat-proxy endpoint and presents itself as the Grok CLI |
| Tests | npm test (vitest), run on every push on macOS, Ubuntu and Windows; some tests are POSIX-only and skip on Windows. Current counts are in the CI logs; method and limits: docs/verification.md |
| CI platforms | macOS, Ubuntu and Windows (macos-latest, ubuntu-latest, windows-latest): lint, tests, build, npm pack --dry-run, privacy sweep, npm audit |
| Daily use | one macOS machine; this is the only environment a person uses every day |
| Install from the packed tarball | scripted cold-install smoke test (smoke-cold.sh) runs in the release workflow; also checked by hand on macOS and on Linux ARM64 |
| Windows | experimental. On Windows 11, headroom install-service registers a "Headroom Daemon" task that starts immediately and serves a per-user named pipe whose name is a hash only. headroom uninstall --home asks the running daemon to shut down over that pipe, removes the task and the home, and exits 0. After an in-place upgrade, headroom install-service restarts the daemon onto the new version, except a daemon started by 0.2.6 or older, which has no shutdown request and must be stopped by hand once (end node.exe in Task Manager). Verified on Windows 11: MCP registration (claude mcp add --scope user headroom -- headroom mcp shows Connected) and a real Claude login read (fresh on the first poll). Not verified on Windows: a slow stop (the 27 second wait is covered by unit tests only) and start at logon and across reboots. Earlier, 0.2.4 was installed on Windows 11 and accounts discover, doctor, status / can / gate / dashboard (UNKNOWN, never a fake number) and the HTML report permissions worked. The process watchdog is inactive on Windows. PowerShell's default execution policy blocks the npm and headroom .ps1 shims; use cmd, or relax the policy |
| Works with | Claude Code through MCP (registered with claude mcp add, covered by mcp-registration.test.ts and daemon-mcp.test.ts); any agent that can run a shell command, through the CLI and --json. Other MCP clients: untested |
| Antigravity | experimental; macOS 14 or later only, and it depends on a private local endpoint that the vendor can change |
| Vendor endpoints | private and unversioned. Headroom pins them, records redacted fixtures and prints UNKNOWN when a shape changes, but it cannot promise they keep working |
An agent that fans out several jobs needs two answers first: can this account afford them, and
which other jobs have already reserved capacity? Vendor screens answer neither for a program, and
a stale reading can send more work to an account that no longer has capacity. Headroom combines
vendor readings with cooperative reservations. When a reading is stale or failed it says UNKNOWN
instead of a number, and can answers NO for it unless you pass --allow-unknown.
One daemon reads quota across Claude, Codex, Antigravity, Grok, Kimi, and local vLLM or llama.cpp pools, keeps history, and detects resets. Antigravity and Grok support is experimental.
Usage analyzers such as ccusage read local usage files and
report estimated costs. Headroom reads the usage and limits your vendors report, from their own
usage endpoints, and answers before work starts: can, gate, route, leases and an inbox, for
agents that dispatch work. They answer different questions and work side by side.
Without a check, an agent finds the limit by hitting it, in the middle of a task. With Headroom it
checks first and tries the next class in your fallback list when the answer is NO. can only
checks; when several jobs start at once, use headroom run so each one reserves its capacity.
Without Headroom
# weekly limit reached mid-task, work stops half done
codex exec "refactor the billing module"
With Headroom
if headroom can codex-build --owner builder; then
codex exec "refactor the billing module"
elif headroom can claude-fable --owner builder; then
claude -p "refactor the billing module"
else
# no class has room: wait for a reset, then check again before dispatching
headroom wait --meter codex-main:main --until-reset --max 6h
fi
headroom run --meter ... --need ... --owner ... -- <command> goes one step further: it checks,
reserves the capacity for the job's duration so other agents that use Headroom see it as taken,
runs the command, and releases the reservation. Runnable examples against synthetic data are in examples/.
| Reads real limits Subscription usage and limits as Claude, Codex, Antigravity, Grok and Kimi report them, plus availability and load for local vLLM or llama.cpp pools. |
Pace, not just percent HARVEST, NORMAL, CONSERVE, FREEZE or UNKNOWN per window, from a straight line burn with a grace period after each reset. |
Go, wait or reroutecan, gate, route, plan, fill and wait answer before the job starts. |
| Reservations Leases and per-meter reserves coordinate capacity among agents that use Headroom ( run, can --lease). |
Fails closed A stale or failed reading prints UNKNOWN, never a number. By default, can answers NO for it. |
Local only A daemon on a 0600 socket (a named pipe on Windows), Headroom's own secrets in the OS store, no telemetry. The CLI checks npm for a newer version at most once a day; turn it off with update_check = false. |
| Reads | Claude · Codex · Antigravity (experimental) · Grok (experimental) · Kimi · local vLLM · local llama.cpp |
| Called from | Claude Code through MCP (tested); any agent that can run a shell command, through the CLI and --json. Other MCP clients: untested. |
| Vendors and meters | Claude all, fable, routines and reported scoped meters; Codex main, spark, credits; Antigravity gemini, claude-gpt; Grok, Kimi; and local vLLM or llama.cpp capacity pools |
| Pace | HARVEST, NORMAL, CONSERVE, FREEZE or UNKNOWN per window, from a straight line burn with a grace period after each reset |
| Decisions | can, gate, route, plan, fill, wait, leases, per-meter reserves, and a spend ledger coordinate shared capacity and pacing |
| Views and automation | Terminal status, dashboard/top (and --html <path> browser report), statusline --render, usage --paste or --clipboard, JSON contract output, local daemon, and MCP tools |
| Operations | Interactive setup; the notify configure picker with calm, quiet and everything presets; inbox; export as JSON or CSV; doctor --bundle; update; uninstall; and shell completion |
Headroom is not a router. Which model is good at what is your opinion and changes monthly. Keep it
in ~/.headroom/routing.toml; Headroom only filters your fallback list by budget. It also never sits in
the request path.
Synthetic data, generated by scripts/render-dashboard-demo.mjs.
Open the terminal overview, or export a local browser snapshot:
headroom dashboard
headroom dashboard --once --ascii
Use Tab to select a meter, v for details, and e for events. Both chart views show
recorded remaining capacity, with gaps where readings are missing or untrusted.
To open the same recorded history in a browser:
headroom dashboard --html report.html
Open the generated file in your browser. The report shows subscription usage and reset times in an overview, with selectable window charts and sample details. It supports light and dark themes and makes no external requests. It is a snapshot: generate it again for newer readings. Existing files are preserved unless you pass --force; new files use mode 0600 on systems that support Unix permissions.
Each of these is a rule the code enforces and a test pins. Past real-world breakage is the reason for every one.
can answers NO for it unless you explicitly pass --allow-unknown.can answers NO for it unless you pass --allow-unknown
(freshnessGate, canConsume, tested in
store-policy.test.ts). Antigravity lanes that report no usage are
classified as blocked, idle or unknown, never filled in
(antigravity-lanes.ts,
antigravity-lane-classifier.test.ts).headroom doctor.
It runs before and independently of the notification config, so a muted channel or
events_off cannot hide it. External channels get nothing per lane; at most one plain-language
message per principal per episode, after 24 hours, held during quiet hours
(canary.ts, stale-lane-canary.test.ts).agy processes that outlive their limit
(process-tree.ts, agy-watchdog.ts,
antigravity-keepalive-stop-recycled-pid.test.ts,
agy-watchdog.test.ts). The test suite itself fails if any
process it started outlives the run (global-leak-gate.ts). The
watchdog and the pid and start-time checks are not active on Windows.secret-tool on Linux, Credential Manager on
Windows) and never written to disk; vendor tokens are read at call time from the vendor's own
store or credential file (for Kimi's manual token and the Moonshot key, a 0600 file you save
yourself) and dropped. Output and logs are redacted
(notify.ts, security.ts,
security.test.ts, SECURITY.md).test/fixtures/antigravity/,
record-antigravity-fixture.sh). The repo
also scans itself and its packed npm tarball for private addresses, emails and home paths
(privacy-sweep.sh, run in CI).Headroom reads Claude, Codex, Grok and Kimi through native TypeScript adapters.
Antigravity is experimental and supported on macOS 14 or later: it requires a logged-in
agy and a running Headroom daemon. The npm and Homebrew packages include a universal
macOS reader, verified by SHA-256 before use. Gemini CLI is not required or supported for consumer subscriptions;
Google ended consumer Gemini CLI access on June 18, 2026.
For Antigravity quota, the bundled macOS reader finds the running Antigravity language server
(the daemon-kept agy) in the process list, takes its local port and, where the process has one,
the local CSRF token from its command line, and asks that server on 127.0.0.1 for its quota
summary. It does not read agy's OAuth or session credential. The daemon also reads the tail of
agy's newest log under ~/.gemini/antigravity-cli/log for login-state markers only. The optional
Antigravity model-list check is off by default and is the one path that uses the Gemini CLI's
OAuth file; see Vendor endpoints and your accounts.
Missing or failed summaries stay UNKNOWN. An idle window with real fractions may carry
a doubt marker when its reset time looks synthetic. A five-hour window entirely absent
from an otherwise-successful response (a genuinely idle rolling window) prints n/a
instead of UNKNOWN and does not block a budget check. The endpoint contracts and native
reader build on CodexBar (MIT).
This synthetic example has 20% usage and another owner reserving 75%. The remaining capacity cannot cover another 10-point job, so the child command never starts:
$ headroom run --meter claude-main:all --need wk:10 --owner builder -- codex exec "Run the tests"
wk needs 10 more but only 0.0 left after 75.0% already leased before the 10% reserve
When there is enough capacity, run reserves it, starts the command, and releases the reservation
when it finishes. The check and reservation are atomic across processes. A plain can or gate
is advisory; use run or can --lease when starting work. These reservations coordinate agents
that use Headroom; they cannot stop unrelated tools from consuming the subscription.
Runnable against synthetic data, no logins needed. Build once, then point the CLI at a seeded home:
npm run build
# sets HEADROOM_HOME to a throwaway demo home
eval "$(node scripts/demo-home.mjs)"
# walks a fallback list, dispatches on the first class with room
bash examples/orchestrator-loop.sh
# refuses a job the budget cannot cover (exit 1)
bash examples/ci-gate.sh
# the MCP call a client sends, over stdio
bash examples/mcp-quota-can.sh
The scripts refuse to run unless HEADROOM_HOME points at that demo home, so they cannot touch a real
~/.headroom, and they call the repo build (dist/cli.js), not a global headroom. They print which
binary they use.
See examples/ for the scripts and the starter accounts.toml, policy.toml and
routing.toml.
--json output and MCP tool result, and its compatibility promiseSeveral adapters read usage endpoints that the vendors do not document as public APIs. Headroom calls them with your own credentials, taken from the vendor CLIs you installed and signed in to on the same machine, and only to read usage: it sends no prompts, changes no account settings, and never writes to another tool's credential store. Use it only with accounts you own. Vendor terms may restrict this kind of access, and a vendor can change or block an endpoint at any time; use it at your own risk. Headroom does not rotate credentials to get past a block or a limit.
| Source | What Headroom calls | Credential | Documented by the vendor |
|---|---|---|---|
| Claude, statusline snapshot (preferred) | No network call: reads the JSON Claude Code passes to its statusLine command | None | Not applicable (local) |
| Claude, usage probe | GET api.anthropic.com/api/oauth/usage | Claude Code's OAuth token, from the macOS Keychain or .credentials.json | No. Sends User-Agent: claude-code/2.1.0 |
| Codex | GET chatgpt.com/backend-api/wham/usage and .../wham/rate-limit-reset-credits; also the Codex CLI's local session logs | ChatGPT token in ~/.codex/auth.json | No. Sends User-Agent: CodexBar; the credits call also sends originator: Codex Desktop |
| Antigravity quota (experimental) | agy's local language server on 127.0.0.1 | agy's local CSRF token from its process command line, where present; not agy's OAuth or session credential | No (private local endpoint) |
| Antigravity model list (experimental, off by default) | cloudcode-pa.googleapis.com/v1internal:loadCodeAssist and :fetchAvailableModels, at most hourly | The Gemini CLI's OAuth file ~/.gemini/oauth_creds.json; an expired token is refreshed in memory at oauth2.googleapis.com with the OAuth client found in the installed Gemini CLI, never written back | No. Sends User-Agent: antigravity and ideType: ANTIGRAVITY. Enable only with antigravity_model_catalog = true in policy.toml |
| Grok (experimental) | GET cli-chat-proxy.grok.com/v1/billing?format=credits and /v1/settings | Bearer token from ~/.grok/auth.json (written by grok login) | No. Sends x-xai-token-auth: xai-grok-cli, the value the Grok CLI sends, so the request presents itself as the Grok CLI |
| Kimi, CLI credential | GET api.kimi.com/coding/v1/usages | Access token from ~/.kimi-code/credentials/kimi-code.json | No. Sends x-msh-platform: kimi_code_cli |
| Kimi, manual token | The www.kimi.com/apiv2 web gateway | A kimi-auth web session token you save yourself to a 0600 file (default ~/.kimi/auth.token) | No |
| Kimi, optional balance | GET api.moonshot.ai/v1/users/me/balance | A Moonshot API key you save to a 0600 moonshot.key file | Yes (Moonshot platform API) |
| Local vLLM, llama.cpp | Your own server at the base_url you configure | None from a vendor | Not applicable |
Per-vendor detail: docs/vendors.md.
Headroom never writes a vendor credential or notification token to disk, and redacts secrets from
its output. On macOS a bundled helper, headroom-claude-probe, reads Claude Code's Keychain token
by running /usr/bin/security, which the Keychain item's own access list admits, keeps it in the
helper's memory and makes the usage request itself, so the token never reaches Node or Headroom's
output. With Claude Code 2.1.263 on macOS 26.5 this needed no Keychain dialog. The helper ships
inside the npm package as a universal binary, verified against a recorded SHA-256 before every use.
Tokens are otherwise read at call time from the vendor's own credential file and dropped after the
request. The daemon listens on a 0600 local socket on macOS and Linux. On Windows it uses a named
pipe where both sides prove they hold a per-daemon session token, kept in a 0600 file under
HEADROOM_HOME. There is no telemetry. Apart from
the vendors you configure and the notification channels you enable, the only request Headroom
makes unprompted is the daily npm version check above, a plain GET with no account data
(update_check = false turns it off); headroom update and headroom engine install contact npm
and GitHub only when you run them. The engine is pinned and checksum verified, and every query
lands in an audit log. Details in SECURITY.md.
Releases are published to npm as headroomd; CHANGELOG.md lists what changed in
each one. Vendor endpoints are private and
change without notice: Headroom pins them, records fixtures, backs off on 401, 403 and 429, and
prints UNKNOWN instead of a stale number. What is and is not verified is in
Platform support and known limitations. Antigravity requires macOS and a daemon-kept agy; see
vendor setup.
Contributions are welcome: see CONTRIBUTING.md and the issues labelled good first issue.
MIT. Third party notices in THIRD_PARTY_NOTICES.md.
Source-derived launch command. Check the maintainer’s required arguments and credentials before running:
npx -y headroomdMerge this template into ~/Library/Application Support/Claude/claude_desktop_config.json. Keep existing servers. Add any arguments, credentials, and permissions required by the maintainer; this template has not been install-tested.
{
"mcpServers": {
"io-github-apertur3-headroom": {
"command": "npx",
"args": [
"-y",
"headroomd"
]
}
}
}Restart Claude Desktop completely for changes to take effect. Confirm the server appears connected in the client’s tool list, then try a read-only example from its documentation.
Claude Desktop setup referenceheadroomdnpmio.github.Apertur3/headroom works with any MCP-compatible client. Copy the config snippet from the Configuration section above and add it to the file shown for your client, then restart the application.
~/Library/Application Support/Claude/claude_desktop_config.jsonRestart Claude Desktop completely for changes to take effect.~/.cursor/mcp.jsonRestart Cursor for changes to take effect..vscode/mcp.jsonReload VS Code window for changes to take effect.~/.codeium/windsurf/mcp_config.jsonRestart Windsurf for changes to take effect..mcp.jsonSave at the project root, then start Claude Code in that project and review the MCP server approval prompt. Keep real credentials out of shared files.