# Claude Code burns ~15–20% of your tokens on a 3-word status line > Source: > Published: 2026-10-29 03:33:42+00:00 # Claude Code burns ~15–20% of your tokens on a 3-word status line. Here's how to turn it off by [Flamerix AI](https://flamerix.ai) · MIT License > Tested on Linux, Claude Code 2.1.257–2.1.312 (see Tested versions). The binary is not modified (`BUN_OPTIONS=--preload`). An update can silently undo it, so see Verify. ## TL;DR ```sh curl -fsSL https://gist.githubusercontent.com/flamerix-ai/c3905705cc4205e5de3011fa2e74efce/raw/no-agent-summary.js -o ~/.local/share/no-agent-summary.js claude daemon stop --any BUN_OPTIONS="${BUN_OPTIONS:+$BUN_OPTIONS }--preload $HOME/.local/share/no-agent-summary.js" claude ``` To make it permanent for every Claude Code process, see [Install](#install). ## The problem Every ~30 seconds, for every background agent, Claude Code sends that agent's **entire transcript** to the agent's own model (usually Opus) and asks it to "describe your most recent action in 3-5 words". The answer only updates the agent's status line in the agents panel; it never reaches the model or your conversation. There is no setting that turns it off, and since 2.1.232 (August 2026) it has been on by default. The anomaly was detected by [DRIM](https://flamerix.ai) in Claude Code's OpenTelemetry export: grouping `claude_code.api_request` events by `query_source` showed `agent_summary` costing **more than the main conversation itself**. | `query_source = agent_summary` | week before the hook | 2 days after | |---|---|---| | share of all Claude Code spend | **16.4 %** (main conversation: 15.7 %) | **0 %** | | share of all API requests | **19.7 %**, about 1 in 5 | **0 %** | | part of that spend on Opus | 96 % | — | | input tokens per output token | ≈ 9,000 : 1 | — | Spend here means Claude Code's own per-request estimate (`cost_usd`), not an invoice: on a subscription, what you lose is rate-limit headroom. We are not the only ones who measured it: [#86879](https://github.com/anthropics/claude-code/issues/86879) collects four independent measurements of 18–26 %. ## The fix (how it works) `no-agent-summary.js` is a Bun preload (~80 lines of code). It wraps `setTimeout`/`setInterval`; when a callback's source text contains a summarizer anchor (e.g. the `[AgentSummary] Timer fired` log line), it returns an inert handle instead of arming the timer. Every other timer passes through untouched. In the OpenTelemetry export the suppressed requests are `claude_code.api_request` events with `query_source = agent_summary`. Why a timer hook rather than something simpler: the module ships as precompiled Bun bytecode, so editing its JS text inside the binary changes nothing, and the API client does not go through a wrapped `globalThis.fetch`. But `Function.prototype.toString` still returns a callback's source even when it runs from bytecode, so the timer can be recognised by a string inside it. The inert timer uses exactly 2³¹−1 ms: Node and Bun treat a larger delay as 1 ms, so an "infinite" delay would fire at once. ## Install 1. Put `no-agent-summary.js` somewhere stable; note its **absolute** path. 2. Set `BUN_OPTIONS` **globally** so every Claude Code process gets it. One of: ```sh # ~/.profile, ~/.bashrc, ~/.zshrc export BUN_OPTIONS="${BUN_OPTIONS:+$BUN_OPTIONS }--preload /abs/path/no-agent-summary.js" ``` ```fish # ~/.config/fish/config.fish set -gx BUN_OPTIONS "--preload /abs/path/no-agent-summary.js" ``` ```ini # ~/.config/environment.d/50-no-agent-summary.conf (systemd user env; also reaches # user services and timers; applies when the user manager next starts, usually next login) BUN_OPTIONS=--preload /abs/path/no-agent-summary.js ``` Or a wrapper named `claude` earlier on `PATH` (the `case` keeps it idempotent when one Claude Code process starts another): ```sh #!/bin/sh HOOK=/abs/path/no-agent-summary.js case " ${BUN_OPTIONS-} " in *" --preload $HOOK "*) ;; *) export BUN_OPTIONS="${BUN_OPTIONS:+$BUN_OPTIONS }--preload $HOOK" ;; esac : "${CC_AGENT_SUMMARY_LOG:=${XDG_RUNTIME_DIR:-/tmp}/no-agent-summary.log}" export CC_AGENT_SUMMARY_LOG exec /path/to/the/real/claude "$@" ``` 3. Restart the daemon and every already-running session, then start Claude Code from an environment that has `BUN_OPTIONS`: ```sh claude daemon stop --any ``` ### Env | variable | values | effect | |---|---|---| | `CC_AGENT_SUMMARY_MODE` | `off` (default), `pass` | `off` suppresses the summary timer. `pass` is the A/B control: loads and logs, arms every timer untouched. Any other value warns on stderr and acts as `off`. | | `CC_AGENT_SUMMARY_LOG` | file path, optional | Appends `preload active mode=… bun=… hooked=…` on load, one line per matched timer (first 20), and an exit count. | | `CC_AGENT_SUMMARY_MARKER` | file path, optional | Overwritten on load with the `preload active …` line. | ## Nuances - **Restart the daemon after install.** The daemon, pty host and pre-warmed `bg-spare` sessions inherit the environment of the client that started the daemon, so a daemon started before `BUN_OPTIONS` was set keeps spawning unhooked sessions. Hence `claude daemon stop --any`. - **Headless runs need it too:** `claude -p`, cron, CI, editor integrations. - **Platform:** Linux tested, macOS and Windows untested. On Windows the `/$bunfs/` gate most likely never installs the hook. - **A/B:** `CC_AGENT_SUMMARY_MODE=pass` loads the hook but arms every timer; the summaries come back, which shows the `off` result is the hook's doing. - **Background processes:** daemon, pty host and `bg-spare` must carry `--preload` in their environment (`/proc//environ` on Linux); if not, restart the daemon. ## Verify (after every update) 1. **Preload loads:** ```sh BUN_OPTIONS="--preload $HOME/.local/share/no-agent-summary.js" CC_AGENT_SUMMARY_LOG=/tmp/nas.log claude --version && cat /tmp/nas.log ``` Expect `preload active mode=off …`. No line: `BUN_OPTIONS` did not reach the process, or the path is not absolute. 2. **Timer suppressed:** with the same `BUN_OPTIONS` and `CC_AGENT_SUMMARY_LOG=/tmp/nas.log`, run a background subagent for a minute or two. The log shows `summary timer #1 suppressed (setTimeout, delay=30000)` and the agent's panel status stops updating. If you export OpenTelemetry, `query_source = agent_summary` should stay at zero; this is the only check that catches every failure mode. ### Fail-open Matching is by **source text**: an anchor must sit inside the callback passed to the timer. If an update breaks that, the hook matches nothing and summaries silently come back. Ways it can happen: - the log line or query-source id is renamed; - the callback is passed via `fn.bind(...)` (no source in `toString`) or another wrapper; - the strings move to a shared constant outside the callback; - the timer moves to an unwrapped API (`timers/promises`, a scheduler loop). So re-run Verify after every update. ## Effect - We run it under every Claude Code process on our machine (2.1.301). Since then there have been zero `agent_summary` requests, and no other side query grew to take its place. - Subagents, background agents, forked skills and background sessions run normally; only the summary fork is skipped. - Visible change: the per-agent panel status stops updating; SDK `task_progress` has no `summary`. - Overhead: one `Function.prototype.toString` per distinct timer callback, cached in a `WeakMap`. `claude --version`: ~10 ms → ~17 ms (one measurement). ## Tested versions Linux x64 binary from npm `@anthropic-ai/claude-code-linux-x64` (its sha256 equals the native installer's `manifest.json` checksum). **Static:** the extracted bundle's summary timer callback carries a hook anchor. **Live:** `claude -p --model haiku` with `CLAUDE_CODE_AGENT_PROGRESS_SUMMARIES=1`, one subagent doing 8 steps of ~20 s, counting `[AgentSummary] Forking` in `--debug-file`. | version | published | sha256 | static | summary forks in a ~2.5-min agent run: no hook / hook `pass` / hook `off` | notes | |---|---|---|---|---|---| | 2.1.312 | 2026-10-27 | `4f4178ce41d8` | OK | **5 / 5 / 0** | `latest` on 2026-10-28; interactive: 6 no hook, 0 `off` | | 2.1.310 | 2026-10-23 | `b73676430af1` | OK | **5 / 5 / 0** | | | 2.1.308 | 2026-10-22 | `356733f185fa` | OK | **5 / 6 / 0** | `stable` on 2026-10-28; the `pass` run's agent took 9 steps instead of 8 | | 2.1.301 | 2026-10-15 | `bc1aad9982c7` | OK | **5 / 5 / 0** | same with earlier hook builds; interactive `off` also 0; in daily use since 2026-10-26, 0 `agent_summary` requests in telemetry | | 2.1.280 | 2026-09-22 | `1e08503dbdf3` | OK | **1 / 1 / 0** (timer fired 11 / 11 / 0) | interactive: `-p` cannot enable summaries on this version. The agent sat at a permission prompt, so later timers skipped the unchanged transcript | | 2.1.257 | 2026-09-01 | `9a64bda9d872` | OK | **1 / 1 / 0** (timer fired 11 / 11 / 0) | same as 2.1.280 | 5 / 5 / 0 = the fork happens on this version, merely loading the hook changes nothing, and `off` removes it. ## Why there is no setting for this - **The documented switch only turns it on.** The SDK option `agentProgressSummaries` defaults to `false`, but in the bundle it is one term of an OR, and every code path that writes it sets `true`. So `false` changes nothing, and the undocumented `CLAUDE_CODE_AGENT_PROGRESS_SUMMARIES` can only enable summaries too. - **The interval belongs to the server.** It comes from a per-model-family server flag and is clamped to 30–240 s. The default is already the minimum, and no value disables the timer. - **The obvious env vars miss.** `DISABLE_NON_ESSENTIAL_MODEL_CALLS`, which some packagers set, does not occur in the binary at all. `CLAUDE_CODE_FORK_SUBAGENT=0` and `CLAUDE_CODE_DISABLE_BACKGROUND_TASKS=1` do stop it, but only by taking fork subagents or background agents with it. - **The prompt cache makes it cheaper, not cheap.** About 98 % of these calls re-read the transcript from cache; the ~2 % that hit a cold cache carry over a third of its cost. - **Cost tools that read transcripts don't see it.** These requests are not written to the session logs on disk ([#104358](https://github.com/anthropics/claude-code/issues/104358)); only the OpenTelemetry export shows them. The docs section on background token usage doesn't list it either, while Agent View's row summaries are documented as a Haiku-class model refreshing every few minutes. - **A cheaper variant already exists, switched off.** 2.1.310 ships a `short` mode: about 2k tokens of notes instead of the full transcript, optionally written by a smaller model. The default is still the full transcript, and only server flags can change it. ### Timeline (2026) | version (published) | what changed | |---|---| | 2.1.32 (Feb 5) | the code first appears; dead in public builds | | 2.1.72 (Mar 9) | reachable as an SDK opt-in | | 2.1.117 (Apr 21) | reachable in the interactive CLI behind the fork gate or a server rollout | | ≤ 2.1.220 (Jul 24) | forked skills are always summarized | | **2.1.232 (Aug 13)** | **on by default** for interactive background agents | | 2.1.300 (Oct 14) | interval becomes server-tunable, 30–240 s | | 2.1.310 (Oct 23) | the cheaper `short` mode lands, switched off | In our telemetry its weekly share of spend went from 3.5–7 % in July (the fork gate was already open for us) to 7.3 % and then 11.8 % in the week we picked up 2.1.233, and to about 16 % by mid-October. ## License and disclaimer MIT © 2026 [Flamerix AI](https://flamerix.ai). Provided **as is**, without warranty of any kind; you use it at your own risk. Flamerix AI is not liable for any damage, data loss or account action arising from its use. Changing a client's runtime behaviour may conflict with the terms of the service you use it with; checking that is on you. "Claude" and "Claude Code" are trademarks of Anthropic, PBC. This project is independent and is not affiliated with, sponsored or endorsed by Anthropic.