{"version":"2.1.219","anchor":"opus-5-carries-an-extra-system-prompt-block-and-suppresses-s","canonical_anchor":"opus-5-carries-an-extra-system-prompt-block-and-suppresses-s","heading":"Opus 5 carries an extra system-prompt block and suppresses subagent nudges","tier":"internal","area":"System Prompt","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.219\/e\/opus-5-carries-an-extra-system-prompt-block-and-suppresses-s","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.219","markdown":"### Opus 5 carries an extra system-prompt block and suppresses subagent nudges\n\nOn some models Claude will stop spinning up subagents or research workflows unless you actually ask for it.\n\n**What**\n\nModels advertising a new capability get an appended prompt block telling the model not to reach for subagents or research workflows unprompted, and the matching steering nudge is turned off for them.\n\n**Details**\n\n- gated on the `opus_5_prompt_bundle` capability, with a remote kill-flag checked inside the capability test (fallback: not killed)\n- the appended block reads \"Do not call the AgentTool unless the user requested it\" and \"Do not use workflows or deep-research unless the user requested it\"\n- application is logged as `tengu_heron_brook_applied` with `fromClientData: !1`\n- the `tengu_heron_brook` string flag still overrides\n- the same capability check feeds the \"thistle grebe\" steering resolver with a new \"model\" source returning \"no_nudges\", suppressing the delegate-to-subagents steering text\n\n**Evidence**\n\n`Do not call the AgentTool unless the user requested it`\n\n- Flag `tengu_heron_brook`: Not enough to say (read for one account on one subscription tier against v2.1.219; this account: no value returned, anonymous baseline: no value returned, compiled default: 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.\n- Area: System Prompt\n- Tier: Under the hood\n- Useful: 3\/5\n- Signal: 0\/5"}