diff --git a/src/contracts/layer3-integrity.ts b/src/contracts/layer3-integrity.ts
new file mode 100644
index 0000000..75ab6f4
--- /dev/null
+++ b/src/contracts/layer3-integrity.ts
@@ -0,0 +1,93 @@
+/**
+ * Layer 3 GuardrailDecision validators. Implements TC-L3-01..07.
+ *
+ * See: https://github.com/Source-Engineering/source-engineering-specifications/blob/main/compatibility-test-suite.md
+ * See: RFC-0003 (v0.4 floor: Layer 3 business guardrails).
+ */
+
+import type { Cots } from "../types.js";
+import { type Result, combine, fail, pass } from "../result.js";
+
+const OUTCOMES = ["accepted", "rejected", "annotated", "escalated"] as const;
+
+const isIso8601 = (value: string): boolean => !Number.isNaN(Date.parse(value));
+
+/**
+ * TC-L3-01..07. Validates every DecisionRecord's optional `guardrail`
+ * field. The field is optional: a missing field passes (TC-L3-07).
+ */
+export const validateGuardrailDecisions = (cots: Cots): Result => {
+  const errors: Result[] = [];
+
+  cots.decisions.forEach((decision, index) => {
+    const g = decision.guardrail;
+    if (g === undefined) {
+      return;
+    }
+
+    if (!(OUTCOMES as readonly string[]).includes(g.decision)) {
+      errors.push(
+        fail(
+          "TC-L3-02",
+          `decisions[${index}].guardrail.decision '${g.decision}' is not in the declared enum (accepted, rejected, annotated, escalated)`
+        )
+      );
+    }
+
+    if (g.decision === "rejected" && g.binding !== true) {
+      errors.push(
+        fail(
+          "TC-L3-03",
+          `decisions[${index}].guardrail: decision is 'rejected' but binding is false. Only a binding rule can reject.`
+        )
+      );
+    }
+
+    if (g.decision === "annotated" && g.binding === true) {
+      errors.push(
+        fail(
+          "TC-L3-04",
+          `decisions[${index}].guardrail: decision is 'annotated' but binding is true. An advisory rule annotates; it does not carry binding force.`
+        )
+      );
+    }
+
+    if (typeof g.rationale !== "string" || g.rationale.trim().length === 0) {
+      errors.push(
+        fail("TC-L3-05", `decisions[${index}].guardrail.rationale is missing or empty. Every GuardrailDecision is recorded with its rationale.`)
+      );
+    }
+
+    if (!isIso8601(g.evaluated_at)) {
+      errors.push(
+        fail("TC-L3-01", `decisions[${index}].guardrail.evaluated_at is not a valid ISO-8601 timestamp`)
+      );
+    }
+
+    if (!/^urn:source-engineering:rule:/.test(g.rule_id)) {
+      errors.push(
+        fail("TC-L3-01", `decisions[${index}].guardrail.rule_id '${g.rule_id}' is not a well-formed rule URN (urn:source-engineering:rule:...)`)
+      );
+    }
+
+    const status = decision.validation_status.status;
+    if (g.decision === "rejected" && status !== "superseded") {
+      errors.push(
+        fail(
+          "TC-L3-06",
+          `decisions[${index}].guardrail: decision is 'rejected' but validation_status.status is '${status}'; it MUST be 'superseded'`
+        )
+      );
+    }
+    if (g.decision === "escalated" && status !== "appealed") {
+      errors.push(
+        fail(
+          "TC-L3-06",
+          `decisions[${index}].guardrail: decision is 'escalated' but validation_status.status is '${status}'; it MUST be 'appealed'`
+        )
+      );
+    }
+  });
+
+  return errors.length > 0 ? combine(...errors) : pass();
+};
diff --git a/src/fixtures/l3-accepted.json b/src/fixtures/l3-accepted.json
new file mode 100644
index 0000000..668fbb8
--- /dev/null
+++ b/src/fixtures/l3-accepted.json
@@ -0,0 +1,165 @@
+{
+  "cots_version": "0.1.0",
+  "cots_id": "urn:source-engineering:cots:00000000-0000-0000-0000-000000000001",
+  "produced_at": "2026-10-11T12:00:00Z",
+  "produced_by": {
+    "system_name": "test-fixture",
+    "system_version": "0.1.0"
+  },
+  "inputs": {
+    "source_artifacts": [
+      {
+        "id": "urn:source-engineering:source:contract-2026-001",
+        "origin": {
+          "system_name": "Acme Contracts",
+          "system_version": "1.0.0",
+          "configuration_hash": "0000000000000000000000000000000000000000000000000000000000000001"
+        },
+        "version": {
+          "content_hash": "1111111111111111111111111111111111111111111111111111111111111111",
+          "issued_at": "2026-10-10T08:00:00Z"
+        },
+        "authority": {
+          "asserted_by": "acme-contracts",
+          "trust_score": 0.95
+        },
+        "temporal_validity": {
+          "valid_from": "2026-10-10T08:00:00Z",
+          "valid_until": null
+        },
+        "content_reference": {
+          "uri": "https://example.com/contracts/2026-001.pdf",
+          "media_type": "application/pdf"
+        }
+      }
+    ]
+  },
+  "context": {
+    "model": {
+      "model_name": "claude-sonnet-4-5",
+      "model_version": "2026-09-15"
+    },
+    "parameters": {
+      "temperature": 0.3,
+      "top_p": 0.95,
+      "prompt_cache_id": null,
+      "tool_budget": 8,
+      "retrieval_depth": 5
+    },
+    "constraints": [
+      {
+        "id": "urn:source-engineering:constraint:jurisdiction-001",
+        "type": "jurisdiction",
+        "scope": "all_decisions",
+        "value": "US-NY"
+      }
+    ]
+  },
+  "decisions": [
+    {
+      "id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+      "decision_text": "The contract is a standard commercial services agreement with mutual indemnification, a 30-day termination notice, and a New York governing-law clause.",
+      "basis_id": "urn:source-engineering:basis:00000000-0000-0000-0000-000000000001",
+      "evidence_chain_ref": "urn:source-engineering:evidence-chain:00000000-0000-0000-0000-000000000001",
+      "validation_status": {
+        "status": "pending",
+        "last_changed_at": "2026-10-11T12:00:00Z",
+        "last_changed_by": "test-fixture"
+      },
+      "responsible_authority": {
+        "authority_id": "claude-sonnet-4-5",
+        "authority_type": "automated"
+      },
+      "audit_history": [
+        {
+          "id": "urn:source-engineering:audit:00000000-0000-0000-0000-000000000001",
+          "action": "created",
+          "performed_by": "test-fixture",
+          "performed_at": "2026-10-11T12:00:00Z",
+          "notes": "Initial creation."
+        }
+      ],
+      "created_at": "2026-10-11T12:00:00Z",
+      "guardrail": {
+        "decision": "accepted",
+        "rule_id": "urn:source-engineering:rule:ny-jurisdiction-001",
+        "rationale": "A rationale in domain terms.",
+        "binding": false,
+        "evaluated_at": "2026-10-30T12:00:00Z",
+        "evaluated_by": "layer3-business-guardrails"
+      }
+    }
+  ],
+  "evidence": {
+    "evidence_chain": [
+      {
+        "decision_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "supporting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "extract_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-7"
+              ],
+              "output": "Section 7.1: Each party shall indemnify and hold harmless...",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.92,
+              "basis": "Direct extraction from the section 7.1 text."
+            },
+            "polarity": "supports"
+          }
+        ],
+        "contradicting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "search_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-12"
+              ],
+              "output": "Section 12.4: This agreement shall be governed by the laws of the State of Delaware.",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.78,
+              "basis": "Contradictory governing-law clause in section 12.4 (the model rejected it because section 14.1 is the prevailing clause)."
+            },
+            "polarity": "contradicts"
+          }
+        ],
+        "claims": [
+          {
+            "id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "decision_record_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+            "claim_text": "The contract contains a mutual indemnification clause in section 7.1.",
+            "claim_type": "factual",
+            "supporting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001"
+            ],
+            "contradicting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002"
+            ]
+          }
+        ]
+      }
+    ]
+  },
+  "validation": {
+    "feedback_surfaces": [
+      {
+        "id": "urn:source-engineering:surface:00000000-0000-0000-0000-000000000001",
+        "type": "appeal",
+        "target": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "endpoint": "https://example.com/appeal/00000000-0000-0000-0000-000000000001",
+        "description": "File an appeal against this decision."
+      }
+    ]
+  }
+}
\ No newline at end of file
diff --git a/src/fixtures/l3-annotated-binding.json b/src/fixtures/l3-annotated-binding.json
new file mode 100644
index 0000000..fbfd16d
--- /dev/null
+++ b/src/fixtures/l3-annotated-binding.json
@@ -0,0 +1,165 @@
+{
+  "cots_version": "0.1.0",
+  "cots_id": "urn:source-engineering:cots:00000000-0000-0000-0000-000000000001",
+  "produced_at": "2026-10-11T12:00:00Z",
+  "produced_by": {
+    "system_name": "test-fixture",
+    "system_version": "0.1.0"
+  },
+  "inputs": {
+    "source_artifacts": [
+      {
+        "id": "urn:source-engineering:source:contract-2026-001",
+        "origin": {
+          "system_name": "Acme Contracts",
+          "system_version": "1.0.0",
+          "configuration_hash": "0000000000000000000000000000000000000000000000000000000000000001"
+        },
+        "version": {
+          "content_hash": "1111111111111111111111111111111111111111111111111111111111111111",
+          "issued_at": "2026-10-10T08:00:00Z"
+        },
+        "authority": {
+          "asserted_by": "acme-contracts",
+          "trust_score": 0.95
+        },
+        "temporal_validity": {
+          "valid_from": "2026-10-10T08:00:00Z",
+          "valid_until": null
+        },
+        "content_reference": {
+          "uri": "https://example.com/contracts/2026-001.pdf",
+          "media_type": "application/pdf"
+        }
+      }
+    ]
+  },
+  "context": {
+    "model": {
+      "model_name": "claude-sonnet-4-5",
+      "model_version": "2026-09-15"
+    },
+    "parameters": {
+      "temperature": 0.3,
+      "top_p": 0.95,
+      "prompt_cache_id": null,
+      "tool_budget": 8,
+      "retrieval_depth": 5
+    },
+    "constraints": [
+      {
+        "id": "urn:source-engineering:constraint:jurisdiction-001",
+        "type": "jurisdiction",
+        "scope": "all_decisions",
+        "value": "US-NY"
+      }
+    ]
+  },
+  "decisions": [
+    {
+      "id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+      "decision_text": "The contract is a standard commercial services agreement with mutual indemnification, a 30-day termination notice, and a New York governing-law clause.",
+      "basis_id": "urn:source-engineering:basis:00000000-0000-0000-0000-000000000001",
+      "evidence_chain_ref": "urn:source-engineering:evidence-chain:00000000-0000-0000-0000-000000000001",
+      "validation_status": {
+        "status": "pending",
+        "last_changed_at": "2026-10-11T12:00:00Z",
+        "last_changed_by": "test-fixture"
+      },
+      "responsible_authority": {
+        "authority_id": "claude-sonnet-4-5",
+        "authority_type": "automated"
+      },
+      "audit_history": [
+        {
+          "id": "urn:source-engineering:audit:00000000-0000-0000-0000-000000000001",
+          "action": "created",
+          "performed_by": "test-fixture",
+          "performed_at": "2026-10-11T12:00:00Z",
+          "notes": "Initial creation."
+        }
+      ],
+      "created_at": "2026-10-11T12:00:00Z",
+      "guardrail": {
+        "decision": "annotated",
+        "rule_id": "urn:source-engineering:rule:ny-jurisdiction-001",
+        "rationale": "A rationale in domain terms.",
+        "binding": true,
+        "evaluated_at": "2026-10-30T12:00:00Z",
+        "evaluated_by": "layer3-business-guardrails"
+      }
+    }
+  ],
+  "evidence": {
+    "evidence_chain": [
+      {
+        "decision_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "supporting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "extract_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-7"
+              ],
+              "output": "Section 7.1: Each party shall indemnify and hold harmless...",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.92,
+              "basis": "Direct extraction from the section 7.1 text."
+            },
+            "polarity": "supports"
+          }
+        ],
+        "contradicting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "search_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-12"
+              ],
+              "output": "Section 12.4: This agreement shall be governed by the laws of the State of Delaware.",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.78,
+              "basis": "Contradictory governing-law clause in section 12.4 (the model rejected it because section 14.1 is the prevailing clause)."
+            },
+            "polarity": "contradicts"
+          }
+        ],
+        "claims": [
+          {
+            "id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "decision_record_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+            "claim_text": "The contract contains a mutual indemnification clause in section 7.1.",
+            "claim_type": "factual",
+            "supporting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001"
+            ],
+            "contradicting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002"
+            ]
+          }
+        ]
+      }
+    ]
+  },
+  "validation": {
+    "feedback_surfaces": [
+      {
+        "id": "urn:source-engineering:surface:00000000-0000-0000-0000-000000000001",
+        "type": "appeal",
+        "target": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "endpoint": "https://example.com/appeal/00000000-0000-0000-0000-000000000001",
+        "description": "File an appeal against this decision."
+      }
+    ]
+  }
+}
\ No newline at end of file
diff --git a/src/fixtures/l3-annotated.json b/src/fixtures/l3-annotated.json
new file mode 100644
index 0000000..b3c0696
--- /dev/null
+++ b/src/fixtures/l3-annotated.json
@@ -0,0 +1,165 @@
+{
+  "cots_version": "0.1.0",
+  "cots_id": "urn:source-engineering:cots:00000000-0000-0000-0000-000000000001",
+  "produced_at": "2026-10-11T12:00:00Z",
+  "produced_by": {
+    "system_name": "test-fixture",
+    "system_version": "0.1.0"
+  },
+  "inputs": {
+    "source_artifacts": [
+      {
+        "id": "urn:source-engineering:source:contract-2026-001",
+        "origin": {
+          "system_name": "Acme Contracts",
+          "system_version": "1.0.0",
+          "configuration_hash": "0000000000000000000000000000000000000000000000000000000000000001"
+        },
+        "version": {
+          "content_hash": "1111111111111111111111111111111111111111111111111111111111111111",
+          "issued_at": "2026-10-10T08:00:00Z"
+        },
+        "authority": {
+          "asserted_by": "acme-contracts",
+          "trust_score": 0.95
+        },
+        "temporal_validity": {
+          "valid_from": "2026-10-10T08:00:00Z",
+          "valid_until": null
+        },
+        "content_reference": {
+          "uri": "https://example.com/contracts/2026-001.pdf",
+          "media_type": "application/pdf"
+        }
+      }
+    ]
+  },
+  "context": {
+    "model": {
+      "model_name": "claude-sonnet-4-5",
+      "model_version": "2026-09-15"
+    },
+    "parameters": {
+      "temperature": 0.3,
+      "top_p": 0.95,
+      "prompt_cache_id": null,
+      "tool_budget": 8,
+      "retrieval_depth": 5
+    },
+    "constraints": [
+      {
+        "id": "urn:source-engineering:constraint:jurisdiction-001",
+        "type": "jurisdiction",
+        "scope": "all_decisions",
+        "value": "US-NY"
+      }
+    ]
+  },
+  "decisions": [
+    {
+      "id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+      "decision_text": "The contract is a standard commercial services agreement with mutual indemnification, a 30-day termination notice, and a New York governing-law clause.",
+      "basis_id": "urn:source-engineering:basis:00000000-0000-0000-0000-000000000001",
+      "evidence_chain_ref": "urn:source-engineering:evidence-chain:00000000-0000-0000-0000-000000000001",
+      "validation_status": {
+        "status": "pending",
+        "last_changed_at": "2026-10-11T12:00:00Z",
+        "last_changed_by": "test-fixture"
+      },
+      "responsible_authority": {
+        "authority_id": "claude-sonnet-4-5",
+        "authority_type": "automated"
+      },
+      "audit_history": [
+        {
+          "id": "urn:source-engineering:audit:00000000-0000-0000-0000-000000000001",
+          "action": "created",
+          "performed_by": "test-fixture",
+          "performed_at": "2026-10-11T12:00:00Z",
+          "notes": "Initial creation."
+        }
+      ],
+      "created_at": "2026-10-11T12:00:00Z",
+      "guardrail": {
+        "decision": "annotated",
+        "rule_id": "urn:source-engineering:rule:ny-jurisdiction-001",
+        "rationale": "A rationale in domain terms.",
+        "binding": false,
+        "evaluated_at": "2026-10-30T12:00:00Z",
+        "evaluated_by": "layer3-business-guardrails"
+      }
+    }
+  ],
+  "evidence": {
+    "evidence_chain": [
+      {
+        "decision_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "supporting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "extract_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-7"
+              ],
+              "output": "Section 7.1: Each party shall indemnify and hold harmless...",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.92,
+              "basis": "Direct extraction from the section 7.1 text."
+            },
+            "polarity": "supports"
+          }
+        ],
+        "contradicting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "search_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-12"
+              ],
+              "output": "Section 12.4: This agreement shall be governed by the laws of the State of Delaware.",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.78,
+              "basis": "Contradictory governing-law clause in section 12.4 (the model rejected it because section 14.1 is the prevailing clause)."
+            },
+            "polarity": "contradicts"
+          }
+        ],
+        "claims": [
+          {
+            "id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "decision_record_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+            "claim_text": "The contract contains a mutual indemnification clause in section 7.1.",
+            "claim_type": "factual",
+            "supporting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001"
+            ],
+            "contradicting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002"
+            ]
+          }
+        ]
+      }
+    ]
+  },
+  "validation": {
+    "feedback_surfaces": [
+      {
+        "id": "urn:source-engineering:surface:00000000-0000-0000-0000-000000000001",
+        "type": "appeal",
+        "target": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "endpoint": "https://example.com/appeal/00000000-0000-0000-0000-000000000001",
+        "description": "File an appeal against this decision."
+      }
+    ]
+  }
+}
\ No newline at end of file
diff --git a/src/fixtures/l3-bad-decision.json b/src/fixtures/l3-bad-decision.json
new file mode 100644
index 0000000..4ffe5b5
--- /dev/null
+++ b/src/fixtures/l3-bad-decision.json
@@ -0,0 +1,165 @@
+{
+  "cots_version": "0.1.0",
+  "cots_id": "urn:source-engineering:cots:00000000-0000-0000-0000-000000000001",
+  "produced_at": "2026-10-11T12:00:00Z",
+  "produced_by": {
+    "system_name": "test-fixture",
+    "system_version": "0.1.0"
+  },
+  "inputs": {
+    "source_artifacts": [
+      {
+        "id": "urn:source-engineering:source:contract-2026-001",
+        "origin": {
+          "system_name": "Acme Contracts",
+          "system_version": "1.0.0",
+          "configuration_hash": "0000000000000000000000000000000000000000000000000000000000000001"
+        },
+        "version": {
+          "content_hash": "1111111111111111111111111111111111111111111111111111111111111111",
+          "issued_at": "2026-10-10T08:00:00Z"
+        },
+        "authority": {
+          "asserted_by": "acme-contracts",
+          "trust_score": 0.95
+        },
+        "temporal_validity": {
+          "valid_from": "2026-10-10T08:00:00Z",
+          "valid_until": null
+        },
+        "content_reference": {
+          "uri": "https://example.com/contracts/2026-001.pdf",
+          "media_type": "application/pdf"
+        }
+      }
+    ]
+  },
+  "context": {
+    "model": {
+      "model_name": "claude-sonnet-4-5",
+      "model_version": "2026-09-15"
+    },
+    "parameters": {
+      "temperature": 0.3,
+      "top_p": 0.95,
+      "prompt_cache_id": null,
+      "tool_budget": 8,
+      "retrieval_depth": 5
+    },
+    "constraints": [
+      {
+        "id": "urn:source-engineering:constraint:jurisdiction-001",
+        "type": "jurisdiction",
+        "scope": "all_decisions",
+        "value": "US-NY"
+      }
+    ]
+  },
+  "decisions": [
+    {
+      "id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+      "decision_text": "The contract is a standard commercial services agreement with mutual indemnification, a 30-day termination notice, and a New York governing-law clause.",
+      "basis_id": "urn:source-engineering:basis:00000000-0000-0000-0000-000000000001",
+      "evidence_chain_ref": "urn:source-engineering:evidence-chain:00000000-0000-0000-0000-000000000001",
+      "validation_status": {
+        "status": "pending",
+        "last_changed_at": "2026-10-11T12:00:00Z",
+        "last_changed_by": "test-fixture"
+      },
+      "responsible_authority": {
+        "authority_id": "claude-sonnet-4-5",
+        "authority_type": "automated"
+      },
+      "audit_history": [
+        {
+          "id": "urn:source-engineering:audit:00000000-0000-0000-0000-000000000001",
+          "action": "created",
+          "performed_by": "test-fixture",
+          "performed_at": "2026-10-11T12:00:00Z",
+          "notes": "Initial creation."
+        }
+      ],
+      "created_at": "2026-10-11T12:00:00Z",
+      "guardrail": {
+        "decision": "blocked",
+        "rule_id": "urn:source-engineering:rule:ny-jurisdiction-001",
+        "rationale": "A rationale in domain terms.",
+        "binding": true,
+        "evaluated_at": "2026-10-30T12:00:00Z",
+        "evaluated_by": "layer3-business-guardrails"
+      }
+    }
+  ],
+  "evidence": {
+    "evidence_chain": [
+      {
+        "decision_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "supporting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "extract_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-7"
+              ],
+              "output": "Section 7.1: Each party shall indemnify and hold harmless...",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.92,
+              "basis": "Direct extraction from the section 7.1 text."
+            },
+            "polarity": "supports"
+          }
+        ],
+        "contradicting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "search_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-12"
+              ],
+              "output": "Section 12.4: This agreement shall be governed by the laws of the State of Delaware.",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.78,
+              "basis": "Contradictory governing-law clause in section 12.4 (the model rejected it because section 14.1 is the prevailing clause)."
+            },
+            "polarity": "contradicts"
+          }
+        ],
+        "claims": [
+          {
+            "id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "decision_record_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+            "claim_text": "The contract contains a mutual indemnification clause in section 7.1.",
+            "claim_type": "factual",
+            "supporting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001"
+            ],
+            "contradicting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002"
+            ]
+          }
+        ]
+      }
+    ]
+  },
+  "validation": {
+    "feedback_surfaces": [
+      {
+        "id": "urn:source-engineering:surface:00000000-0000-0000-0000-000000000001",
+        "type": "appeal",
+        "target": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "endpoint": "https://example.com/appeal/00000000-0000-0000-0000-000000000001",
+        "description": "File an appeal against this decision."
+      }
+    ]
+  }
+}
\ No newline at end of file
diff --git a/src/fixtures/l3-escalated.json b/src/fixtures/l3-escalated.json
new file mode 100644
index 0000000..df29488
--- /dev/null
+++ b/src/fixtures/l3-escalated.json
@@ -0,0 +1,165 @@
+{
+  "cots_version": "0.1.0",
+  "cots_id": "urn:source-engineering:cots:00000000-0000-0000-0000-000000000001",
+  "produced_at": "2026-10-11T12:00:00Z",
+  "produced_by": {
+    "system_name": "test-fixture",
+    "system_version": "0.1.0"
+  },
+  "inputs": {
+    "source_artifacts": [
+      {
+        "id": "urn:source-engineering:source:contract-2026-001",
+        "origin": {
+          "system_name": "Acme Contracts",
+          "system_version": "1.0.0",
+          "configuration_hash": "0000000000000000000000000000000000000000000000000000000000000001"
+        },
+        "version": {
+          "content_hash": "1111111111111111111111111111111111111111111111111111111111111111",
+          "issued_at": "2026-10-10T08:00:00Z"
+        },
+        "authority": {
+          "asserted_by": "acme-contracts",
+          "trust_score": 0.95
+        },
+        "temporal_validity": {
+          "valid_from": "2026-10-10T08:00:00Z",
+          "valid_until": null
+        },
+        "content_reference": {
+          "uri": "https://example.com/contracts/2026-001.pdf",
+          "media_type": "application/pdf"
+        }
+      }
+    ]
+  },
+  "context": {
+    "model": {
+      "model_name": "claude-sonnet-4-5",
+      "model_version": "2026-09-15"
+    },
+    "parameters": {
+      "temperature": 0.3,
+      "top_p": 0.95,
+      "prompt_cache_id": null,
+      "tool_budget": 8,
+      "retrieval_depth": 5
+    },
+    "constraints": [
+      {
+        "id": "urn:source-engineering:constraint:jurisdiction-001",
+        "type": "jurisdiction",
+        "scope": "all_decisions",
+        "value": "US-NY"
+      }
+    ]
+  },
+  "decisions": [
+    {
+      "id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+      "decision_text": "The contract is a standard commercial services agreement with mutual indemnification, a 30-day termination notice, and a New York governing-law clause.",
+      "basis_id": "urn:source-engineering:basis:00000000-0000-0000-0000-000000000001",
+      "evidence_chain_ref": "urn:source-engineering:evidence-chain:00000000-0000-0000-0000-000000000001",
+      "validation_status": {
+        "status": "appealed",
+        "last_changed_at": "2026-10-11T12:00:00Z",
+        "last_changed_by": "test-fixture"
+      },
+      "responsible_authority": {
+        "authority_id": "claude-sonnet-4-5",
+        "authority_type": "automated"
+      },
+      "audit_history": [
+        {
+          "id": "urn:source-engineering:audit:00000000-0000-0000-0000-000000000001",
+          "action": "created",
+          "performed_by": "test-fixture",
+          "performed_at": "2026-10-11T12:00:00Z",
+          "notes": "Initial creation."
+        }
+      ],
+      "created_at": "2026-10-11T12:00:00Z",
+      "guardrail": {
+        "decision": "escalated",
+        "rule_id": "urn:source-engineering:rule:ny-jurisdiction-001",
+        "rationale": "A rationale in domain terms.",
+        "binding": true,
+        "evaluated_at": "2026-10-30T12:00:00Z",
+        "evaluated_by": "layer3-business-guardrails"
+      }
+    }
+  ],
+  "evidence": {
+    "evidence_chain": [
+      {
+        "decision_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "supporting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "extract_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-7"
+              ],
+              "output": "Section 7.1: Each party shall indemnify and hold harmless...",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.92,
+              "basis": "Direct extraction from the section 7.1 text."
+            },
+            "polarity": "supports"
+          }
+        ],
+        "contradicting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "search_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-12"
+              ],
+              "output": "Section 12.4: This agreement shall be governed by the laws of the State of Delaware.",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.78,
+              "basis": "Contradictory governing-law clause in section 12.4 (the model rejected it because section 14.1 is the prevailing clause)."
+            },
+            "polarity": "contradicts"
+          }
+        ],
+        "claims": [
+          {
+            "id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "decision_record_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+            "claim_text": "The contract contains a mutual indemnification clause in section 7.1.",
+            "claim_type": "factual",
+            "supporting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001"
+            ],
+            "contradicting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002"
+            ]
+          }
+        ]
+      }
+    ]
+  },
+  "validation": {
+    "feedback_surfaces": [
+      {
+        "id": "urn:source-engineering:surface:00000000-0000-0000-0000-000000000001",
+        "type": "appeal",
+        "target": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "endpoint": "https://example.com/appeal/00000000-0000-0000-0000-000000000001",
+        "description": "File an appeal against this decision."
+      }
+    ]
+  }
+}
\ No newline at end of file
diff --git a/src/fixtures/l3-no-rationale.json b/src/fixtures/l3-no-rationale.json
new file mode 100644
index 0000000..f5fbe3f
--- /dev/null
+++ b/src/fixtures/l3-no-rationale.json
@@ -0,0 +1,165 @@
+{
+  "cots_version": "0.1.0",
+  "cots_id": "urn:source-engineering:cots:00000000-0000-0000-0000-000000000001",
+  "produced_at": "2026-10-11T12:00:00Z",
+  "produced_by": {
+    "system_name": "test-fixture",
+    "system_version": "0.1.0"
+  },
+  "inputs": {
+    "source_artifacts": [
+      {
+        "id": "urn:source-engineering:source:contract-2026-001",
+        "origin": {
+          "system_name": "Acme Contracts",
+          "system_version": "1.0.0",
+          "configuration_hash": "0000000000000000000000000000000000000000000000000000000000000001"
+        },
+        "version": {
+          "content_hash": "1111111111111111111111111111111111111111111111111111111111111111",
+          "issued_at": "2026-10-10T08:00:00Z"
+        },
+        "authority": {
+          "asserted_by": "acme-contracts",
+          "trust_score": 0.95
+        },
+        "temporal_validity": {
+          "valid_from": "2026-10-10T08:00:00Z",
+          "valid_until": null
+        },
+        "content_reference": {
+          "uri": "https://example.com/contracts/2026-001.pdf",
+          "media_type": "application/pdf"
+        }
+      }
+    ]
+  },
+  "context": {
+    "model": {
+      "model_name": "claude-sonnet-4-5",
+      "model_version": "2026-09-15"
+    },
+    "parameters": {
+      "temperature": 0.3,
+      "top_p": 0.95,
+      "prompt_cache_id": null,
+      "tool_budget": 8,
+      "retrieval_depth": 5
+    },
+    "constraints": [
+      {
+        "id": "urn:source-engineering:constraint:jurisdiction-001",
+        "type": "jurisdiction",
+        "scope": "all_decisions",
+        "value": "US-NY"
+      }
+    ]
+  },
+  "decisions": [
+    {
+      "id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+      "decision_text": "The contract is a standard commercial services agreement with mutual indemnification, a 30-day termination notice, and a New York governing-law clause.",
+      "basis_id": "urn:source-engineering:basis:00000000-0000-0000-0000-000000000001",
+      "evidence_chain_ref": "urn:source-engineering:evidence-chain:00000000-0000-0000-0000-000000000001",
+      "validation_status": {
+        "status": "superseded",
+        "last_changed_at": "2026-10-11T12:00:00Z",
+        "last_changed_by": "test-fixture"
+      },
+      "responsible_authority": {
+        "authority_id": "claude-sonnet-4-5",
+        "authority_type": "automated"
+      },
+      "audit_history": [
+        {
+          "id": "urn:source-engineering:audit:00000000-0000-0000-0000-000000000001",
+          "action": "created",
+          "performed_by": "test-fixture",
+          "performed_at": "2026-10-11T12:00:00Z",
+          "notes": "Initial creation."
+        }
+      ],
+      "created_at": "2026-10-11T12:00:00Z",
+      "guardrail": {
+        "decision": "rejected",
+        "rule_id": "urn:source-engineering:rule:ny-jurisdiction-001",
+        "rationale": "",
+        "binding": true,
+        "evaluated_at": "2026-10-30T12:00:00Z",
+        "evaluated_by": "layer3-business-guardrails"
+      }
+    }
+  ],
+  "evidence": {
+    "evidence_chain": [
+      {
+        "decision_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "supporting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "extract_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-7"
+              ],
+              "output": "Section 7.1: Each party shall indemnify and hold harmless...",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.92,
+              "basis": "Direct extraction from the section 7.1 text."
+            },
+            "polarity": "supports"
+          }
+        ],
+        "contradicting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "search_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-12"
+              ],
+              "output": "Section 12.4: This agreement shall be governed by the laws of the State of Delaware.",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.78,
+              "basis": "Contradictory governing-law clause in section 12.4 (the model rejected it because section 14.1 is the prevailing clause)."
+            },
+            "polarity": "contradicts"
+          }
+        ],
+        "claims": [
+          {
+            "id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "decision_record_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+            "claim_text": "The contract contains a mutual indemnification clause in section 7.1.",
+            "claim_type": "factual",
+            "supporting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001"
+            ],
+            "contradicting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002"
+            ]
+          }
+        ]
+      }
+    ]
+  },
+  "validation": {
+    "feedback_surfaces": [
+      {
+        "id": "urn:source-engineering:surface:00000000-0000-0000-0000-000000000001",
+        "type": "appeal",
+        "target": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "endpoint": "https://example.com/appeal/00000000-0000-0000-0000-000000000001",
+        "description": "File an appeal against this decision."
+      }
+    ]
+  }
+}
\ No newline at end of file
diff --git a/src/fixtures/l3-rejected-not-binding.json b/src/fixtures/l3-rejected-not-binding.json
new file mode 100644
index 0000000..988de5d
--- /dev/null
+++ b/src/fixtures/l3-rejected-not-binding.json
@@ -0,0 +1,165 @@
+{
+  "cots_version": "0.1.0",
+  "cots_id": "urn:source-engineering:cots:00000000-0000-0000-0000-000000000001",
+  "produced_at": "2026-10-11T12:00:00Z",
+  "produced_by": {
+    "system_name": "test-fixture",
+    "system_version": "0.1.0"
+  },
+  "inputs": {
+    "source_artifacts": [
+      {
+        "id": "urn:source-engineering:source:contract-2026-001",
+        "origin": {
+          "system_name": "Acme Contracts",
+          "system_version": "1.0.0",
+          "configuration_hash": "0000000000000000000000000000000000000000000000000000000000000001"
+        },
+        "version": {
+          "content_hash": "1111111111111111111111111111111111111111111111111111111111111111",
+          "issued_at": "2026-10-10T08:00:00Z"
+        },
+        "authority": {
+          "asserted_by": "acme-contracts",
+          "trust_score": 0.95
+        },
+        "temporal_validity": {
+          "valid_from": "2026-10-10T08:00:00Z",
+          "valid_until": null
+        },
+        "content_reference": {
+          "uri": "https://example.com/contracts/2026-001.pdf",
+          "media_type": "application/pdf"
+        }
+      }
+    ]
+  },
+  "context": {
+    "model": {
+      "model_name": "claude-sonnet-4-5",
+      "model_version": "2026-09-15"
+    },
+    "parameters": {
+      "temperature": 0.3,
+      "top_p": 0.95,
+      "prompt_cache_id": null,
+      "tool_budget": 8,
+      "retrieval_depth": 5
+    },
+    "constraints": [
+      {
+        "id": "urn:source-engineering:constraint:jurisdiction-001",
+        "type": "jurisdiction",
+        "scope": "all_decisions",
+        "value": "US-NY"
+      }
+    ]
+  },
+  "decisions": [
+    {
+      "id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+      "decision_text": "The contract is a standard commercial services agreement with mutual indemnification, a 30-day termination notice, and a New York governing-law clause.",
+      "basis_id": "urn:source-engineering:basis:00000000-0000-0000-0000-000000000001",
+      "evidence_chain_ref": "urn:source-engineering:evidence-chain:00000000-0000-0000-0000-000000000001",
+      "validation_status": {
+        "status": "superseded",
+        "last_changed_at": "2026-10-11T12:00:00Z",
+        "last_changed_by": "test-fixture"
+      },
+      "responsible_authority": {
+        "authority_id": "claude-sonnet-4-5",
+        "authority_type": "automated"
+      },
+      "audit_history": [
+        {
+          "id": "urn:source-engineering:audit:00000000-0000-0000-0000-000000000001",
+          "action": "created",
+          "performed_by": "test-fixture",
+          "performed_at": "2026-10-11T12:00:00Z",
+          "notes": "Initial creation."
+        }
+      ],
+      "created_at": "2026-10-11T12:00:00Z",
+      "guardrail": {
+        "decision": "rejected",
+        "rule_id": "urn:source-engineering:rule:ny-jurisdiction-001",
+        "rationale": "A rationale in domain terms.",
+        "binding": false,
+        "evaluated_at": "2026-10-30T12:00:00Z",
+        "evaluated_by": "layer3-business-guardrails"
+      }
+    }
+  ],
+  "evidence": {
+    "evidence_chain": [
+      {
+        "decision_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "supporting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "extract_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-7"
+              ],
+              "output": "Section 7.1: Each party shall indemnify and hold harmless...",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.92,
+              "basis": "Direct extraction from the section 7.1 text."
+            },
+            "polarity": "supports"
+          }
+        ],
+        "contradicting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "search_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-12"
+              ],
+              "output": "Section 12.4: This agreement shall be governed by the laws of the State of Delaware.",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.78,
+              "basis": "Contradictory governing-law clause in section 12.4 (the model rejected it because section 14.1 is the prevailing clause)."
+            },
+            "polarity": "contradicts"
+          }
+        ],
+        "claims": [
+          {
+            "id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "decision_record_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+            "claim_text": "The contract contains a mutual indemnification clause in section 7.1.",
+            "claim_type": "factual",
+            "supporting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001"
+            ],
+            "contradicting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002"
+            ]
+          }
+        ]
+      }
+    ]
+  },
+  "validation": {
+    "feedback_surfaces": [
+      {
+        "id": "urn:source-engineering:surface:00000000-0000-0000-0000-000000000001",
+        "type": "appeal",
+        "target": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "endpoint": "https://example.com/appeal/00000000-0000-0000-0000-000000000001",
+        "description": "File an appeal against this decision."
+      }
+    ]
+  }
+}
\ No newline at end of file
diff --git a/src/fixtures/l3-rejected.json b/src/fixtures/l3-rejected.json
new file mode 100644
index 0000000..8917fda
--- /dev/null
+++ b/src/fixtures/l3-rejected.json
@@ -0,0 +1,165 @@
+{
+  "cots_version": "0.1.0",
+  "cots_id": "urn:source-engineering:cots:00000000-0000-0000-0000-000000000001",
+  "produced_at": "2026-10-11T12:00:00Z",
+  "produced_by": {
+    "system_name": "test-fixture",
+    "system_version": "0.1.0"
+  },
+  "inputs": {
+    "source_artifacts": [
+      {
+        "id": "urn:source-engineering:source:contract-2026-001",
+        "origin": {
+          "system_name": "Acme Contracts",
+          "system_version": "1.0.0",
+          "configuration_hash": "0000000000000000000000000000000000000000000000000000000000000001"
+        },
+        "version": {
+          "content_hash": "1111111111111111111111111111111111111111111111111111111111111111",
+          "issued_at": "2026-10-10T08:00:00Z"
+        },
+        "authority": {
+          "asserted_by": "acme-contracts",
+          "trust_score": 0.95
+        },
+        "temporal_validity": {
+          "valid_from": "2026-10-10T08:00:00Z",
+          "valid_until": null
+        },
+        "content_reference": {
+          "uri": "https://example.com/contracts/2026-001.pdf",
+          "media_type": "application/pdf"
+        }
+      }
+    ]
+  },
+  "context": {
+    "model": {
+      "model_name": "claude-sonnet-4-5",
+      "model_version": "2026-09-15"
+    },
+    "parameters": {
+      "temperature": 0.3,
+      "top_p": 0.95,
+      "prompt_cache_id": null,
+      "tool_budget": 8,
+      "retrieval_depth": 5
+    },
+    "constraints": [
+      {
+        "id": "urn:source-engineering:constraint:jurisdiction-001",
+        "type": "jurisdiction",
+        "scope": "all_decisions",
+        "value": "US-NY"
+      }
+    ]
+  },
+  "decisions": [
+    {
+      "id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+      "decision_text": "The contract is a standard commercial services agreement with mutual indemnification, a 30-day termination notice, and a New York governing-law clause.",
+      "basis_id": "urn:source-engineering:basis:00000000-0000-0000-0000-000000000001",
+      "evidence_chain_ref": "urn:source-engineering:evidence-chain:00000000-0000-0000-0000-000000000001",
+      "validation_status": {
+        "status": "superseded",
+        "last_changed_at": "2026-10-11T12:00:00Z",
+        "last_changed_by": "test-fixture"
+      },
+      "responsible_authority": {
+        "authority_id": "claude-sonnet-4-5",
+        "authority_type": "automated"
+      },
+      "audit_history": [
+        {
+          "id": "urn:source-engineering:audit:00000000-0000-0000-0000-000000000001",
+          "action": "created",
+          "performed_by": "test-fixture",
+          "performed_at": "2026-10-11T12:00:00Z",
+          "notes": "Initial creation."
+        }
+      ],
+      "created_at": "2026-10-11T12:00:00Z",
+      "guardrail": {
+        "decision": "rejected",
+        "rule_id": "urn:source-engineering:rule:ny-jurisdiction-001",
+        "rationale": "A rationale in domain terms.",
+        "binding": true,
+        "evaluated_at": "2026-10-30T12:00:00Z",
+        "evaluated_by": "layer3-business-guardrails"
+      }
+    }
+  ],
+  "evidence": {
+    "evidence_chain": [
+      {
+        "decision_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "supporting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "extract_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-7"
+              ],
+              "output": "Section 7.1: Each party shall indemnify and hold harmless...",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.92,
+              "basis": "Direct extraction from the section 7.1 text."
+            },
+            "polarity": "supports"
+          }
+        ],
+        "contradicting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "search_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-12"
+              ],
+              "output": "Section 12.4: This agreement shall be governed by the laws of the State of Delaware.",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.78,
+              "basis": "Contradictory governing-law clause in section 12.4 (the model rejected it because section 14.1 is the prevailing clause)."
+            },
+            "polarity": "contradicts"
+          }
+        ],
+        "claims": [
+          {
+            "id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "decision_record_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+            "claim_text": "The contract contains a mutual indemnification clause in section 7.1.",
+            "claim_type": "factual",
+            "supporting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001"
+            ],
+            "contradicting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002"
+            ]
+          }
+        ]
+      }
+    ]
+  },
+  "validation": {
+    "feedback_surfaces": [
+      {
+        "id": "urn:source-engineering:surface:00000000-0000-0000-0000-000000000001",
+        "type": "appeal",
+        "target": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "endpoint": "https://example.com/appeal/00000000-0000-0000-0000-000000000001",
+        "description": "File an appeal against this decision."
+      }
+    ]
+  }
+}
\ No newline at end of file
diff --git a/src/fixtures/l3-status-inconsistent.json b/src/fixtures/l3-status-inconsistent.json
new file mode 100644
index 0000000..9b3efd0
--- /dev/null
+++ b/src/fixtures/l3-status-inconsistent.json
@@ -0,0 +1,165 @@
+{
+  "cots_version": "0.1.0",
+  "cots_id": "urn:source-engineering:cots:00000000-0000-0000-0000-000000000001",
+  "produced_at": "2026-10-11T12:00:00Z",
+  "produced_by": {
+    "system_name": "test-fixture",
+    "system_version": "0.1.0"
+  },
+  "inputs": {
+    "source_artifacts": [
+      {
+        "id": "urn:source-engineering:source:contract-2026-001",
+        "origin": {
+          "system_name": "Acme Contracts",
+          "system_version": "1.0.0",
+          "configuration_hash": "0000000000000000000000000000000000000000000000000000000000000001"
+        },
+        "version": {
+          "content_hash": "1111111111111111111111111111111111111111111111111111111111111111",
+          "issued_at": "2026-10-10T08:00:00Z"
+        },
+        "authority": {
+          "asserted_by": "acme-contracts",
+          "trust_score": 0.95
+        },
+        "temporal_validity": {
+          "valid_from": "2026-10-10T08:00:00Z",
+          "valid_until": null
+        },
+        "content_reference": {
+          "uri": "https://example.com/contracts/2026-001.pdf",
+          "media_type": "application/pdf"
+        }
+      }
+    ]
+  },
+  "context": {
+    "model": {
+      "model_name": "claude-sonnet-4-5",
+      "model_version": "2026-09-15"
+    },
+    "parameters": {
+      "temperature": 0.3,
+      "top_p": 0.95,
+      "prompt_cache_id": null,
+      "tool_budget": 8,
+      "retrieval_depth": 5
+    },
+    "constraints": [
+      {
+        "id": "urn:source-engineering:constraint:jurisdiction-001",
+        "type": "jurisdiction",
+        "scope": "all_decisions",
+        "value": "US-NY"
+      }
+    ]
+  },
+  "decisions": [
+    {
+      "id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+      "decision_text": "The contract is a standard commercial services agreement with mutual indemnification, a 30-day termination notice, and a New York governing-law clause.",
+      "basis_id": "urn:source-engineering:basis:00000000-0000-0000-0000-000000000001",
+      "evidence_chain_ref": "urn:source-engineering:evidence-chain:00000000-0000-0000-0000-000000000001",
+      "validation_status": {
+        "status": "pending",
+        "last_changed_at": "2026-10-11T12:00:00Z",
+        "last_changed_by": "test-fixture"
+      },
+      "responsible_authority": {
+        "authority_id": "claude-sonnet-4-5",
+        "authority_type": "automated"
+      },
+      "audit_history": [
+        {
+          "id": "urn:source-engineering:audit:00000000-0000-0000-0000-000000000001",
+          "action": "created",
+          "performed_by": "test-fixture",
+          "performed_at": "2026-10-11T12:00:00Z",
+          "notes": "Initial creation."
+        }
+      ],
+      "created_at": "2026-10-11T12:00:00Z",
+      "guardrail": {
+        "decision": "rejected",
+        "rule_id": "urn:source-engineering:rule:ny-jurisdiction-001",
+        "rationale": "A rationale in domain terms.",
+        "binding": true,
+        "evaluated_at": "2026-10-30T12:00:00Z",
+        "evaluated_by": "layer3-business-guardrails"
+      }
+    }
+  ],
+  "evidence": {
+    "evidence_chain": [
+      {
+        "decision_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "supporting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "extract_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-7"
+              ],
+              "output": "Section 7.1: Each party shall indemnify and hold harmless...",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.92,
+              "basis": "Direct extraction from the section 7.1 text."
+            },
+            "polarity": "supports"
+          }
+        ],
+        "contradicting_evidence": [
+          {
+            "id": "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002",
+            "claim_id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "source_id": "urn:source-engineering:source:contract-2026-001",
+            "transformation": {
+              "operation": "search_clause",
+              "inputs": [
+                "https://example.com/contracts/2026-001.pdf#section-12"
+              ],
+              "output": "Section 12.4: This agreement shall be governed by the laws of the State of Delaware.",
+              "recorded_at": "2026-10-11T12:00:00Z"
+            },
+            "uncertainty": {
+              "calibrated_score": 0.78,
+              "basis": "Contradictory governing-law clause in section 12.4 (the model rejected it because section 14.1 is the prevailing clause)."
+            },
+            "polarity": "contradicts"
+          }
+        ],
+        "claims": [
+          {
+            "id": "urn:source-engineering:claim:00000000-0000-0000-0000-000000000001",
+            "decision_record_id": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+            "claim_text": "The contract contains a mutual indemnification clause in section 7.1.",
+            "claim_type": "factual",
+            "supporting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000001"
+            ],
+            "contradicting_evidence": [
+              "urn:source-engineering:evidence:00000000-0000-0000-0000-000000000002"
+            ]
+          }
+        ]
+      }
+    ]
+  },
+  "validation": {
+    "feedback_surfaces": [
+      {
+        "id": "urn:source-engineering:surface:00000000-0000-0000-0000-000000000001",
+        "type": "appeal",
+        "target": "urn:source-engineering:decision:00000000-0000-0000-0000-000000000001",
+        "endpoint": "https://example.com/appeal/00000000-0000-0000-0000-000000000001",
+        "description": "File an appeal against this decision."
+      }
+    ]
+  }
+}
\ No newline at end of file
diff --git a/src/runner.ts b/src/runner.ts
index fa966e6..741ad36 100644
--- a/src/runner.ts
+++ b/src/runner.ts
@@ -18,6 +18,7 @@ import { validateAuditHistory, validateAuditHistoryOrdered } from "./contracts/l
 import { validateFiveParts, validateFeedbackSurfaces } from "./contracts/five-parts.js";
 import { validateLayer2Records } from "./contracts/layer2-integrity.js";
 import { validateUrnGrammar, validateChainResolution, validateTemporalOrdering, validateRecursiveChains } from "./contracts/semantic-integrity.js";
+import { validateGuardrailDecisions } from "./contracts/layer3-integrity.js";
 
 export const run = (cots: Cots): Result => {
   return combine(
@@ -35,7 +36,8 @@ export const run = (cots: Cots): Result => {
     validateUrnGrammar(cots),
     validateChainResolution(cots),
     validateTemporalOrdering(cots),
-    validateRecursiveChains(cots)
+    validateRecursiveChains(cots),
+    validateGuardrailDecisions(cots)
   );
 };
 
diff --git a/src/types.ts b/src/types.ts
index daf4cab..0971028 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -125,6 +125,19 @@ export interface DecisionRecord {
   created_at: ISO8601;
   /** Layer 2 Validation record (COTS schema v1.1.0, RFC-0001). Optional. */
   validation?: Layer2Validation;
+  /** Layer 3 GuardrailDecision (COTS schema v1.3.0, RFC-0003). Optional. */
+  guardrail?: GuardrailDecision;
+}
+
+export type GuardrailOutcome = "accepted" | "rejected" | "annotated" | "escalated";
+
+export interface GuardrailDecision {
+  decision: GuardrailOutcome;
+  rule_id: URI;
+  rationale: string;
+  binding: boolean;
+  evaluated_at: ISO8601;
+  evaluated_by?: string;
 }
 
 export type FlagType =
diff --git a/tests/layer3.test.ts b/tests/layer3.test.ts
new file mode 100644
index 0000000..4d62a27
--- /dev/null
+++ b/tests/layer3.test.ts
@@ -0,0 +1,68 @@
+/**
+ * Layer 3 GuardrailDecision test cases (TC-L3-01..07), derived from the
+ * canonical test cases in the Source Engineering specifications and RFC-0003.
+ */
+
+import { describe, it, expect } from "vitest";
+import { readFileSync } from "node:fs";
+import { resolve } from "node:path";
+import { fileURLToPath } from "node:url";
+import { dirname, join } from "node:path";
+import { validateGuardrailDecisions } from "../src/contracts/layer3-integrity.js";
+import { run } from "../src/runner.js";
+import type { Cots } from "../src/types.js";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const FIXTURES = join(__dirname, "..", "src", "fixtures");
+
+const load = (name: string): Cots =>
+  JSON.parse(readFileSync(resolve(FIXTURES, name), "utf-8")) as Cots;
+
+describe("Layer 3 GuardrailDecisions", () => {
+  it("TC-L3-01: well-formed guardrail records pass (accepted, rejected, annotated, escalated)", () => {
+    for (const f of ["l3-accepted.json", "l3-rejected.json", "l3-annotated.json", "l3-escalated.json"]) {
+      const result = validateGuardrailDecisions(load(f));
+      expect(result.errors, f).toHaveLength(0);
+    }
+  });
+
+  it("TC-L3-02: an unknown guardrail decision fails", () => {
+    const result = validateGuardrailDecisions(load("l3-bad-decision.json"));
+    expect(result.errors.some((e) => e.test_id === "TC-L3-02")).toBe(true);
+  });
+
+  it("TC-L3-03: a rejection that is not binding fails", () => {
+    const result = validateGuardrailDecisions(load("l3-rejected-not-binding.json"));
+    expect(result.errors.some((e) => e.test_id === "TC-L3-03")).toBe(true);
+  });
+
+  it("TC-L3-04: an annotation marked binding fails", () => {
+    const result = validateGuardrailDecisions(load("l3-annotated-binding.json"));
+    expect(result.errors.some((e) => e.test_id === "TC-L3-04")).toBe(true);
+  });
+
+  it("TC-L3-05: an empty rationale fails", () => {
+    const result = validateGuardrailDecisions(load("l3-no-rationale.json"));
+    expect(result.errors.some((e) => e.test_id === "TC-L3-05")).toBe(true);
+  });
+
+  it("TC-L3-06: a rejected decision whose status is not superseded fails", () => {
+    const result = validateGuardrailDecisions(load("l3-status-inconsistent.json"));
+    expect(result.errors.some((e) => e.test_id === "TC-L3-06")).toBe(true);
+  });
+
+  it("TC-L3-07: a v1.2.0 COTS without the guardrail field passes", () => {
+    const result = validateGuardrailDecisions(load("conformant.json"));
+    expect(result.errors).toHaveLength(0);
+  });
+
+  it("the full runner fails the non-binding rejection end-to-end", () => {
+    const result = run(load("l3-rejected-not-binding.json"));
+    expect(result.status).toBe("fail");
+  });
+
+  it("the full runner passes the well-formed rejection end-to-end", () => {
+    const result = run(load("l3-rejected.json"));
+    expect(result.errors.filter((e) => e.test_id.startsWith("TC-L3"))).toHaveLength(0);
+  });
+});