Claude Code Background Agent Summaries Burn Up to 20% of Token Budgets

What changed#

Developer Flamerix AI published a workaround (no-agent-summary.js) to disable non-essential background status requests in Claude Code. Enabled by default since version 2.1.232, Claude Code runs an automated summary process roughly every 30 seconds for each active background agent.

To update a 3-to-5 word status string in the CLI user interface, Claude Code re-sends each subagent’s complete conversation transcript back to its model—frequently Claude Opus. These periodic status checks generate API calls without returning context or results to the main prompt loop.

Why it matters#

OpenTelemetry metrics exported from Claude Code runs show that requests tagged with query_source = agent_summary account for a major portion of overall usage:

• Request Share: Status summaries represented 19.7% of all Claude Code API requests—nearly one out of every five calls.
• Cost Overhead: Summary requests constituted 16.4% of total estimated USD spend in telemetry, consuming more resources than the main user conversation (15.7%).
• Model Selection: Approximately 96% of the token spend for these background updates was billed against Claude Opus.
• Token Ratios: The process generates an input-to-output token ratio of roughly 9,000 input tokens for every single output token generated.

Multiple community measurements report overall rate-limit and token overhead between 18% and 26%. On subscription tiers, this idle polling directly degrades available rate-limit capacity.

What to do next#

Because Claude Code ships as a precompiled Bun bytecode binary, editing source text directly or hooking globalThis.fetch does not intercept the timer. The solution uses Bun’s runtime options to inspect function strings before timers schedule execution.

1. Save the script: Place no-agent-summary.js in a permanent local folder (e.g., ~/.local/share/no-agent-summary.js).
2. Set global Bun preloads: Export BUN_OPTIONS in your shell configuration (~/.bashrc, ~/.zshrc, or systemd environment definitions):

   1
   export BUN_OPTIONS="${BUN_OPTIONS:+$BUN_OPTIONS }--preload /path/to/no-agent-summary.js"

3. Restart running daemons: Terminate all active processes and pre-warmed background sessions so they inherit the updated environment:

   1
   claude daemon stop --any

The script wraps setTimeout and setInterval. It runs Function.prototype.toString on callback signatures to detect anchor strings like [AgentSummary]. When matched, it overrides the timer with an inert handle set to $2^{31}-1$ ms, preventing the API dispatch while allowing standard non-summary timers to pass through.

Sources#

• Flamerix AI Gist: no-agent-summary.js