{"version":"2.1.91","anchor":"sandbox-unavailable-error-in-stream-json-mode","canonical_anchor":"sandbox-unavailable-error-in-stream-json-mode","heading":"Sandbox Unavailable Error in Stream-JSON Mode","tier":null,"area":null,"scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.91\/e\/sandbox-unavailable-error-in-stream-json-mode","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.91","markdown":"### Sandbox Unavailable Error in Stream-JSON Mode\n\n**What**\n\nWhen running in headless mode (`--output-format stream-json`) and the sandbox is required but unavailable, Claude Code now emits a proper JSON error result instead of only writing to stderr.\n\n**Details**\n\n- Error message includes: `\"Sandbox required but unavailable: {reason}. Set sandbox.failIfUnavailable=false to allow unsandboxed execution.\"`\n- The JSON result includes all standard fields (session_id, uuid, duration, etc.) for proper parsing by automation tools\n\n**Evidence**\n\nHeadless sandbox error handling (search for `\"Sandbox required but unavailable:\"`)"}