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Sweep 22 Sep 2026 · 17:19Z Build v2.1.280 501 read Stable v2.1.267 Latest v2.1.280 Next v2.1.280 Feeds RSS JSON llms.txt Unofficial
Claude Code v2.1.275 ·

Subagent concurrency cap simplified to one env-configurable limit

Subagent spawning is now limited only by a single concurrency cap, configurable via CLAUDE_CODE_MAX_CONCURRENT_SUBAGENTS

TierUse it nowhow much it should matter to you
Useful4my rating, 1 to 5
Signal2worth watching, 1 to 5
AreaSubagentswhat it touches
KindNew Featuresin v2.1.275,
Group of 2 Use it now Notable

Subagent spawning is now limited only by a single concurrency cap, configurable via CLAUDE_CODE_MAX_CONCURRENT_SUBAGENTS

What Subagent spawning previously refused once a subagent hit both a fixed lifetime total and a fixed concurrent-run cap. Now only the concurrent-run limit remains, defaulting to 20 and overridable with the CLAUDE_CODE_MAX_CONCURRENT_SUBAGENTS environment variable. When the cap is reached, a new subagent launch is refused with a message telling the user to raise CLAUDE_CODE_MAX_CONCURRENT_SUBAGENTS, and the refusal is recorded as a subagent_concurrency_cap event.

Why Dropping the separate lifetime-total cap means subagents are no longer blocked just because many have run in sequence over a long session; only how many are running at once matters now, and that limit can be tuned per environment.

Read from
Names in the bundleCLAUDE_CODE_MAX_CONCURRENT_SUBAGENTS
Feature flag
tengu_amber_kestrel Not enough to say

Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.

This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.275: off

These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.

Read once, for one account on one subscription tier, against v2.1.275. It isn't a statement about your account. What a flag value here can and cannot tell you

See this entry in the whole of v2.1.275 →

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