{"record":{"id":"b85116e393ef8a2b","repo":"Hmbown/CodeWhale","slug":"fleet-authority-fingerprint-expected-is-not-a-form-this","errorCode":null,"errorMessage":"Fleet authority fingerprint `{expected}` is not a form this build understands; refusing the spawn rather than launching an unverified child","messagePattern":"Fleet authority fingerprint `(.+?)` is not a form this build understands; refusing the spawn rather than launching an unverified child","errorType":"exception","errorClass":"anyhow::Error","httpStatus":null,"severity":"error","filePath":"crates/tui/src/tools/subagent/mod.rs","lineNumber":11003,"sourceCode":"/// The fingerprint is produced by `ChildAuthority::fingerprint` and names every\n/// field of the envelope. Only four of them survive into the spawn input as\n/// distinct keys — `write_authority`, `max_depth`, `allowed_tools`,\n/// `disallowed_tools` — and those are exactly the four this function can and\n/// does verify. The remaining fields (`tools`, `network`, `shell`, `posture`)\n/// are *derivations* the Fleet used to compute those four, so a divergence in\n/// any of them shows up in one of the four; verifying the wire form is\n/// therefore the stronger check, not the weaker one, because it is the value\n/// the child is actually constructed from.\n///\n/// Fails closed in every ambiguous case: an unparseable fingerprint is a\n/// refusal, not a pass.\nfn verify_fleet_authority_input(expected: &str, input: &Value) -> Result<()> {\n    let fields: std::collections::HashMap<&str, &str> = expected\n        .split(';')\n        .filter_map(|part| part.split_once('='))\n        .collect();\n    if !expected.starts_with(\"v1;\") || fields.len() < 8 {\n        return Err(anyhow!(\n            \"Fleet authority fingerprint `{expected}` is not a form this build understands; \\\n             refusing the spawn rather than launching an unverified child\"\n        ));\n    }\n\n    let listed = |key: &str| -> String {\n        let mut values: Vec<String> = input\n            .get(key)\n            .and_then(Value::as_array)\n            .map(|items| {\n                items\n                    .iter()\n                    .filter_map(Value::as_str)\n                    .map(str::to_string)\n                    .collect()\n            })\n            .unwrap_or_default();\n        values.sort();","sourceCodeStart":10985,"sourceCodeEnd":11021,"githubUrl":"https://github.com/Hmbown/CodeWhale/blob/73e0f67d83c59909b571efdfc88c4bc28c309cb1/crates/tui/src/tools/subagent/mod.rs#L10985-L11021","documentation":"verify_fleet_authority_input parses a Fleet authority fingerprint string of the form \"v1;key=value;...\" and requires at least 8 key=value fields. If the fingerprint does not start with \"v1;\" or has fewer than 8 fields, the build refuses to spawn the child agent rather than launching it with an unverifiable authority receipt. This is a fail-loud guard against forged or malformed authority data.","triggerScenarios":"Spawning a sub-agent whose fleet authority fingerprint string is from an older/other version (missing v1 prefix), was truncated in transit or storage, or was hand-edited so fewer than 8 fields remain.","commonSituations":"Mixing builds where one writes a newer fingerprint format the other cannot parse, copy-paste truncation of the receipt in config, or a stale persisted authority token from a previous release.","solutions":["Regenerate the Fleet authority fingerprint with the current build so it uses the supported v1 format with all 8+ fields","Verify the full fingerprint string was copied — check for truncation (missing trailing fields)","Check that both parent and child tooling are the same version and share one fingerprint format","Do not hand-edit the fingerprint; re-issue it through the fleet authority issuance path"],"exampleFix":"// before: truncated receipt\nlet fp = \"v1;depth=2;allow=read\";\n// after: full v1 receipt with all required fields\nlet fp = \"v1;depth=2;allow=read;deny=write;budget=...;model=...;scope=...;issuer=...;ts=...\";","handlingStrategy":"validation","validationCode":"fn is_supported_fingerprint(fp: &str) -> bool {\n    fp.starts_with(\"v1;\") && fp.split(';').filter(|p| p.contains('=')).count() >= 8\n}","typeGuard":null,"tryCatchPattern":"match spawn_child(&fp, &input) {\n    Err(e) if e.to_string().contains(\"not a form this build understands\") => {\n        let fp = reissue_fingerprint(); // regenerate with current build\n        spawn_child(&fp, &input)\n    }\n    other => other,\n}","preventionTips":["Never hand-edit authority fingerprints; re-issue them","Keep parent and child tooling on the same version","Validate the fingerprint format at receipt storage time, not just spawn time"],"tags":["subagent","fleet","authority","validation"],"backgroundTag":"invalid-argument-format","analyzedSha":"73e0f67d83c59909b571efdfc88c4bc28c309cb1","analyzedAt":"2026-09-22T01:30:00.501Z","contentChangedAt":"2026-09-22T01:30:00.501Z","schemaVersion":2},"datasetVersion":"2026-09-22T16:17:23.217Z"}