{"version":"2.1.261","anchor":"subagent-harness-tail-size-accounting-behind-tengu-swift-w","canonical_anchor":"subagent-harness-tail-size-accounting-behind-tengu-swift-w","heading":"Subagent \"harness tail\" size accounting behind tengu_swift_whistle","tier":"soon","area":"Subagents","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.261\/e\/subagent-harness-tail-size-accounting-behind-tengu-swift-w","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.261","markdown":"### Subagent \"harness tail\" size accounting behind tengu_swift_whistle\n\nSubagent report truncation accounting for a 'harness tail' section stays inert behind a flag.\n\nNew code paths, gated behind `tengu_swift_whistle`, control whether subagent `SendMessage` report truncation reserves extra budget for a `harnessTail`\/`inlineHandback` section, and whether a telemetry counter fires when that path is taken. The logic is reachable from report formatting on agent completion and from `mapToolResultToToolResultBlockParam` for `SendMessage`, but the whole branch stays inert until the gate is enabled.\n\n- Flag `tengu_swift_whistle`: Not enough to say (read for one account on one subscription tier against v2.1.261; this account: no value returned, anonymous baseline: no value returned, compiled default: 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.\n- Area: Subagents\n- Names: `tengu_swift_whistle`\n- Tier: Nothing to try yet\n- Useful: 2\/5\n- Signal: 3\/5\n- Present in the build but not switched on"}