A new environment variable that controls how strongly Claude is nudged toward (or away from) spawning subagents. Three modes let you tune the behavior for different workflows.
CLAUDE_CODE_THISTLE_GREBE=counter_steer claude
CLAUDE_CODE_THISTLE_GREBE=no_nudges claude
# or leave unset / set to "default" for existing behaviordefault— no change from existing behavior. Claude receives normal guidance about when to spawn subagents and is encouraged to parallelize work with the Agent tool.no_nudges— suppresses proactive suggestions to spawn subagents. Claude no longer sees prompts suggesting it fan out to multiple agents for broad exploration. The post-plan-approval hint ("consider spawning named teammates to parallelize the work") is also suppressed. The concurrency note shown in the tool-use header is hidden.counter_steer— injects an active counter-delegation block into the system prompt. Claude sees explicit guidance discouraging delegation for small tasks: "Do the work inline when it is a small, bounded sub-task — a few file reads, one search, a short edit, a single check. Do not spawn a subagent for work you could finish yourself in a handful of tool calls." This mode also hides suggestions to use the Agent tool in Glob, Grep, and Plan mode descriptions.
The value can alternatively be set server-side via client data or as a GrowthBook feature flag (tengu_thistle_grebe). The env var takes precedence over the other sources.
New steering resolver and mode constant "tengu_thistle_grebe", counter-steer instruction block (search for "Delegating to subagents" and "Do the work inline when it is a small, bounded sub-task")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
tengu_thistle_grebe Not enough to sayNothing 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 v2.1.215: not a boolean we can read
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 v2.1.215. It isn't a statement about your account. What a flag value here can and cannot tell you
A reading is one sample. Claude Code evaluates its flags remotely, so no client sees the targeting rule behind a value and this says nothing about your account.
A reading is one sample. Claude Code evaluates its flags remotely, so no client sees the targeting rule behind a value and this says nothing about your account.