Flamerix AI finds Claude Code summary feature uses 15-20% of tokens
The analysis of OpenTelemetry data also found about one in five API requests goes to the agent summary function, which cannot be turned off in settings.
Flamerix AI analyzed OpenTelemetry exports from Claude Code and found that the agent summary feature accounts for roughly 15-20% of total token spending, according to gigazine.net. About one in five API requests is sent for the feature, and with Opus models token consumption of 18-26% was confirmed.
Claude Code sends the entire conversation record of every background agent to that agent's model about every 30 seconds, asking for a 3-5 word description of its recent actions. The replies are used only to update the status line in the agent panel and provide no information to the model or the conversation, according to the analysis.
The feature has been enabled by default since Claude Code version 2.1.232 in August 2026 and cannot be disabled through settings. Flamerix AI has released a workaround: a Bun preload script called no-agent-summary.js, about 70 lines of JavaScript that wraps setTimeout() and blocks timers whose callbacks contain the anchor '[AgentSummary] Timer fired'.
The script does not modify the Claude Code binary and is loaded via Bun's --preload option, so Claude Code updates do not disable it. Flamerix AI reports it works on Linux, macOS and Windows, though Windows support is limited, and adds roughly 10ms to 17ms of overhead per timer callback.
The Claude Code research group run by IT venture Arrowheads does not recommend using no-agent-summary.js, citing anchor changes on updates and the fact that using the BUN_OPTIONS environment variable loads it into all Bun instances on the machine. A separate issue was also reported in which Opus includes the user's email address in the User-Agent header of requests.
Quick answers
What does the agent summary feature do in Claude Code?
It sends each background agent's full conversation record to that agent's model about every 30 seconds for a 3-5 word description, used only to update the status line in the agent panel.
Can the agent summary feature be disabled in settings?
No. It has been enabled by default since Claude Code version 2.1.232 in August 2026 and cannot be disabled via settings.
What is no-agent-summary.js?
A roughly 70-line Bun preload script from Flamerix AI that wraps setTimeout() and blocks timers whose callbacks contain the anchor '[AgentSummary] Timer fired', without modifying the Claude Code binary.