{"version":"2.1.217","anchor":"tengu-heron-tallow-new-feature-gate-feature-flagged","canonical_anchor":"tengu-heron-tallow-new-feature-gate-feature-flagged","heading":"tengu_heron_tallow \u2014 New Feature Gate [Feature-Flagged]","tier":null,"area":null,"scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.217\/e\/tengu-heron-tallow-new-feature-gate-feature-flagged","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.217","markdown":"### `tengu_heron_tallow` \u2014 New Feature Gate [Feature-Flagged]\n\n**What**\n\nA new feature flag `tengu_heron_tallow` is available. It can also be enabled via the `CLAUDE_CODE_HERON_TALLOW` environment variable or via managed settings.\n\n**Status**\n\nFeature-flagged (also overridable via `CLAUDE_CODE_HERON_TALLOW` env var)\n\n**Details**\n\n- `Ohd()` returns `true` if `Z.CLAUDE_CODE_HERON_TALLOW` env var is truthy, the managed settings object has `tengu_heron_tallow: true`, or the feature flag is on via `Ke()`\n- `Ohd()` is called inside `mks()`, which generates the hint text appended to tool-not-found errors in the model context when a tool call cannot be routed to any registered tool\n- When `Ohd()` is `true` and the tool name resolves to an existing-but-not-enabled tool: the hint changes from `\"X exists but is not enabled in this context. Use one of the available tools instead.\"` to `\"X is disabled for this session, in subagents as well as here.\"`\n- When `Ohd()` is `true` and the tool is in the known-but-session-unavailable set (`sat()`): the hint changes from `\"X is not available in this context. Use one of the available tools instead.\"` to `\"X is disabled for this session.\"`\n- The change shifts the model's framing from \"try a different tool\" toward \"this tool is a session-level prohibition\", which may affect how the model responds to tool-call failures in restricted sessions\n\n**Evidence**\n\n`Ohd()` function (search for `\"CLAUDE_CODE_HERON_TALLOW\"`) and its changed hint strings (search for `\"is disabled for this session, in subagents as well as here\"`)\n\n- Flag `tengu_heron_tallow`: Off in both readings (read for one account on one subscription tier against v2.1.217; 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."}