diff --git a/schemas/environment.schema.json b/schemas/environment.schema.json
index 10c7b40..567e92b 100644
--- a/schemas/environment.schema.json
+++ b/schemas/environment.schema.json
@@ -27,20 +27,23 @@
       "type": "object",
       "required": ["bucket", "lock_table"],
       "properties": {
-        "bucket": {"type": "string", "description": "S3 state bucket name."},
+        "bucket": {"type": "string", "pattern": "^[a-z0-9][a-z0-9.-]{1,61}[a-z0-9]$", "description": "S3 state bucket name (lowercase, 3-63 chars, dots/hyphens)."},
         "lock_table": {"type": "string", "description": "DynamoDB lock table name."}
-      }
+      },
+      "additionalProperties": false
     },
     "network": {
       "type": "object",
       "required": ["vpc_cidr", "azs"],
       "properties": {
-        "vpc_cidr": {"type": "string", "description": "VPC CIDR block."},
-        "azs": {"type": "array", "items": {"type": "string"}, "description": "Availability zones."}
-      }
+        "vpc_cidr": {"type": "string", "pattern": "^[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}/[0-9]{1,2}$", "description": "VPC CIDR block (e.g. 10.0.0.0/16)."},
+        "azs": {"type": "array", "items": {"type": "string"}, "maxItems": 6, "description": "Availability zones (max 6)."}
+      },
+      "additionalProperties": false
     },
     "runner_role_arn": {
       "type": "string",
+      "pattern": "^arn:aws:iam::[0-9]{12}:role/.+$",
       "description": "The IAM role ARN surfaced to the consumer's repo via ABAC."
     },
     "autonomy": {
@@ -54,5 +57,6 @@
       "maximum": 1,
       "description": "The confidence gate threshold for this environment (dev 0.50, qa 0.75, prod 0.90, dr 0.95)."
     }
-  }
+  },
+  "additionalProperties": false
 }
\ No newline at end of file
diff --git a/tests/test_environment_schema.py b/tests/test_environment_schema.py
index bba468f..713dc9b 100644
--- a/tests/test_environment_schema.py
+++ b/tests/test_environment_schema.py
@@ -96,4 +96,64 @@ def test_account_id_is_12_digits():
     for env_file in ENV_FILES:
         env = json.loads((ENV_DIR / env_file).read_text())
         assert len(env["account_id"]) == 12
-        assert env["account_id"].isdigit()
\ No newline at end of file
+        assert env["account_id"].isdigit()
+
+
+def test_v14_schema_rejects_undocumented_fields():
+    """v1.14 (REQ-145): additionalProperties: false rejects unknown fields."""
+    schema = json.loads(SCHEMA.read_text())
+    bad_env = {
+        "name": "dev",
+        "account_id": "123456789012",
+        "region": "us-east-1",
+        "state_backend": {"bucket": "test", "lock_table": "test"},
+        "network": {"vpc_cidr": "10.0.0.0/16", "azs": ["us-east-1a"]},
+        "runner_role_arn": "arn:aws:iam::123456789012:role/test",
+        "autonomy": "full",
+        "confidence_threshold": 0.5,
+        "rogue_field": "should be rejected"
+    }
+    with pytest.raises(jsonschema.ValidationError, match="Additional properties are not allowed"):
+        jsonschema.validate(bad_env, schema)
+
+
+def test_v14_schema_validates_bucket_name_format():
+    """v1.14 (REQ-145): state_backend.bucket must match S3 naming rules."""
+    schema = json.loads(SCHEMA.read_text())
+    bad_env = {
+        "name": "dev", "account_id": "123456789012", "region": "us-east-1",
+        "state_backend": {"bucket": "Invalid_Bucket!", "lock_table": "test"},
+        "network": {"vpc_cidr": "10.0.0.0/16", "azs": ["us-east-1a"]},
+        "runner_role_arn": "arn:aws:iam::123456789012:role/test",
+        "autonomy": "full", "confidence_threshold": 0.5
+    }
+    with pytest.raises(jsonschema.ValidationError, match="does not match"):
+        jsonschema.validate(bad_env, schema)
+
+
+def test_v14_schema_validates_arn_format():
+    """v1.14 (REQ-145): runner_role_arn must match ARN format."""
+    schema = json.loads(SCHEMA.read_text())
+    bad_env = {
+        "name": "dev", "account_id": "123456789012", "region": "us-east-1",
+        "state_backend": {"bucket": "test", "lock_table": "test"},
+        "network": {"vpc_cidr": "10.0.0.0/16", "azs": ["us-east-1a"]},
+        "runner_role_arn": "not-an-arn",
+        "autonomy": "full", "confidence_threshold": 0.5
+    }
+    with pytest.raises(jsonschema.ValidationError, match="does not match"):
+        jsonschema.validate(bad_env, schema)
+
+
+def test_v14_schema_validates_cidr_format():
+    """v1.14 (REQ-145): vpc_cidr must match CIDR format."""
+    schema = json.loads(SCHEMA.read_text())
+    bad_env = {
+        "name": "dev", "account_id": "123456789012", "region": "us-east-1",
+        "state_backend": {"bucket": "test", "lock_table": "test"},
+        "network": {"vpc_cidr": "not-a-cidr", "azs": ["us-east-1a"]},
+        "runner_role_arn": "arn:aws:iam::123456789012:role/test",
+        "autonomy": "full", "confidence_threshold": 0.5
+    }
+    with pytest.raises(jsonschema.ValidationError, match="does not match"):
+        jsonschema.validate(bad_env, schema)
\ No newline at end of file