{
  "spec": "LRFS v1.0",
  "spec_section": "LRFS v1.0 §4",
  "category": "failure-modes",
  "id": "003-signature-algorithm-mismatch",
  "description": "Declared signing algorithm is incompatible with the provided signature byte length. Conformant readers MUST reject before attempting verification.",
  "inputs": {
    "layers": {
      "llmind:text": "hello world"
    },
    "signing_algorithm": "hmac-sha256",
    "signature_bytes_hex": "3045022100c0fffee0fffee0fffee0fffee0fffee0fffee0fffee0fffee0fffee00220c0fffee0fffee0fffee0fffee0fffee0fffee0fffee0fffee0fffee0fffee0ff"
  },
  "expected_outcome": "reject",
  "reason": "HMAC-SHA256 produces exactly 32 bytes (64 hex chars). This fixture declares `hmac-sha256` but supplies 70 bytes (140 hex chars) — the length is inconsistent with the declared algorithm. Conformant readers MUST reject without even attempting HMAC verification."
}