{"version":"2.1.227","anchor":"headless-write-failures-produce-a-result-object-not-silence","canonical_anchor":"headless-write-failures-produce-a-result-object-not-silence","heading":"Headless write failures produce a result object, not silence","tier":"notice","area":"Headless Mode","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.227\/e\/headless-write-failures-produce-a-result-object-not-silence","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.227","markdown":"### Headless write failures produce a result object, not silence\n\nHeadless output write failures now produce a proper failed result object in stream-json.\n\n**What**\n\nIf a message cannot be written to the headless output stream, Claude now writes an `Error:` line to stderr, marks the turn's summary as failed, and in stream-json mode emits a `result` object with an `error_during_execution` subtype built by a shared helper.\n\n**Details**\n\n- The stderr line begins `Could not write a message to the output stream`.\n- Paired with a `tengu_headless_fatal_error` event carrying the site, message type, control subtype, drained message count, outstanding stdout bytes and whether stdout was destroyed.\n- None of this existed in v2.1.226.\n\n**Evidence**\n\n`Could not write a message to the output stream`\n\n- Area: Headless Mode\n- Tier: You'll notice\n- Useful: 4\/5\n- Signal: 2\/5"}