{"version":"2.1.223","anchor":"new-prompt-variant-experiment-for-two-tools","canonical_anchor":"new-prompt-variant-experiment-for-two-tools","heading":"New prompt-variant experiment for two tools","tier":"soon","area":"Agents","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.223\/e\/new-prompt-variant-experiment-for-two-tools","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.223","markdown":"### New prompt-variant experiment for two tools\n\nAn alternate prompt wording for two tools exists but stays off unless you set an environment variable.\n\n**What**\n\nTwo model-scoped predicates were added that swap in an alternate prompt variant for their tools. Off by default in this build.\n\n**Details**\n\n- Enabled by the environment variable `CLAUDE_CODE_PARCHMENT_FERN`, a per-model `opus_5_prompt_bundle` capability, a settings key, or the gate `tengu_parchment_fern`, which falls back to false.\n- One of the two predicates is additionally conditioned on the existing per-model `tengu_velvet_mallet` gate.\n- When active, the variants appear as marker prefixes in the prompt-cache key.\n\n**Evidence**\n\n`tengu_parchment_fern`\n\n- Flag `tengu_parchment_fern`: Off in both readings (read for one account on one subscription tier against v2.1.223; this account: off, anonymous baseline: off, 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- Flag `tengu_velvet_mallet`: Off in both readings (read for one account on one subscription tier against v2.1.223; this account: off, anonymous baseline: off, 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: Agents\n- Names: `CLAUDE_CODE_PARCHMENT_FERN`\n- Tier: Nothing to try yet\n- Useful: 2\/5\n- Signal: 3\/5\n- Present in the build but not switched on"}