diff --git a/docs/decision-evidence.md b/docs/decision-evidence.md
index 2a41ec5c..70f6d15e 100644
--- a/docs/decision-evidence.md
+++ b/docs/decision-evidence.md
@@ -21,12 +21,18 @@ resource is missing. Callers can validate `evidence.as_dict()` without adding a
 JSON Schema runtime dependency to EgressWeave.
 
 The v1 contract requires every emitted field, including the non-empty
-`address_count` total and its IPv4/IPv6 family counts. `allowed_methods` may be
-an intentionally empty deny-all set, but any method token must already be an
-uppercase normalized token and `CONNECT` is never accepted. These checks
+`address_count` total and its IPv4/IPv6 family counts. Its `authority` field is a
+bounded canonical lowercase ASCII hostname plus TCP port, matching the runtime
+comparison form after IDNA processing. The schema rejects URL syntax,
+credentials, paths, IP literals and legacy numeric spellings—including dotted
+hexadecimal forms—non-canonical hostname spellings, DNS names beyond the runtime
+length ceiling, and ports outside `1..65535` rather than accepting sensitive or
+impossible authority shapes that runtime evidence cannot emit. `allowed_methods`
+may be an intentionally empty deny-all set, but any method token must already be
+an uppercase normalized token and `CONNECT` is never accepted. These checks
 describe evidence for a decision that was already authorized; the artifact is
-subject to purpose limitation and does not authorize a request, path,
-credential, tenant, or destination by itself.
+subject to purpose limitation and does not authorize a request, path, credential,
+tenant, or destination by itself.
 
 ## Data minimization
 
diff --git a/src/egressweave/schemas/decision-evidence-v1.schema.json b/src/egressweave/schemas/decision-evidence-v1.schema.json
index b0343d51..9c53a887 100644
--- a/src/egressweave/schemas/decision-evidence-v1.schema.json
+++ b/src/egressweave/schemas/decision-evidence-v1.schema.json
@@ -20,7 +20,9 @@
     },
     "authority": {
       "type": "string",
-      "minLength": 1
+      "minLength": 3,
+      "maxLength": 259,
+      "pattern": "^(?=.{1,253}:)(?![0-9.]+:)(?!0(?:\\.)*x[a-z0-9.-]*:)(?:[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?)(?:\\.(?:[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?))*:(?:[1-9]|[1-9][0-9]{1,3}|[1-5][0-9]{4}|6[0-4][0-9]{3}|65[0-4][0-9]{2}|655[0-2][0-9]|6553[0-5])$"
     },
     "allowed_methods": {
       "type": "array",
diff --git a/tests/test_decision_evidence_authority_schema.py b/tests/test_decision_evidence_authority_schema.py
new file mode 100644
index 00000000..b4524513
--- /dev/null
+++ b/tests/test_decision_evidence_authority_schema.py
@@ -0,0 +1,79 @@
+"""Regressions for the privacy-minimized decision-evidence authority schema."""
+
+from __future__ import annotations
+
+import re
+
+import egressweave
+
+
+def _authority_schema() -> dict[str, object]:
+    """Return the versioned authority field schema from the public loader."""
+    schema = egressweave.get_decision_evidence_json_schema()
+    properties = schema["properties"]
+    assert isinstance(properties, dict)
+    authority = properties["authority"]
+    assert isinstance(authority, dict)
+    return authority
+
+
+def test_authority_schema_matches_runtime_canonical_shape() -> None:
+    """Accept only bounded lowercase hostname-and-port evidence authorities."""
+    authority = _authority_schema()
+    pattern = authority["pattern"]
+
+    assert isinstance(pattern, str)
+    assert authority["type"] == "string"
+    assert authority["minLength"] == 3
+    assert authority["maxLength"] == 259
+
+    for value in (
+        "api.example.com:443",
+        "service-1:80",
+        "xn--bcher-kva.example:8443",
+        "a:1",
+        "api.example.com:65535",
+    ):
+        assert re.fullmatch(pattern, value) is not None
+
+
+def test_authority_schema_rejects_non_runtime_and_sensitive_shapes() -> None:
+    """Keep URL syntax, credentials, paths, literals, and invalid ports out."""
+    pattern = _authority_schema()["pattern"]
+    assert isinstance(pattern, str)
+
+    for value in (
+        "https://api.example.com:443/private",
+        "https://user:secret@example.com/private?token=value",
+        "api.example.com/private:443",
+        "api.example.com",
+        "API.EXAMPLE.COM:443",
+        "api.example.com.:443",
+        "api..example.com:443",
+        "-api.example.com:443",
+        "api.example.com-:443",
+        "127.0.0.1:443",
+        "0x7f000001:443",
+        "0x7f.0.0.1:443",
+        "0.x7f:443",
+        "[2001:db8::1]:443",
+        "api.example.com:0",
+        "api.example.com:65536",
+        "api.example.com:99999",
+    ):
+        assert re.fullmatch(pattern, value) is None
+
+
+def test_authority_schema_bounds_hostname_length_independent_of_port_width() -> None:
+    """Reject evidence hostnames that exceed the runtime DNS-name ceiling."""
+    pattern = _authority_schema()["pattern"]
+    assert isinstance(pattern, str)
+
+    label = "a" * 63
+    maximum_hostname = f"{label}.{label}.{label}.{'b' * 61}"
+    oversized_hostname = f"{label}.{label}.{label}.{'b' * 62}"
+
+    assert len(maximum_hostname) == 253
+    assert len(oversized_hostname) == 254
+    assert re.fullmatch(pattern, f"{maximum_hostname}:1") is not None
+    assert re.fullmatch(pattern, f"{oversized_hostname}:1") is None
diff --git a/tests/test_decision_evidence_schema_current_main.py b/tests/test_decision_evidence_schema_current_main.py
index 1288a184..eb7ad021 100644
--- a/tests/test_decision_evidence_schema_current_main.py
+++ b/tests/test_decision_evidence_schema_current_main.py
@@ -11,6 +11,18 @@
 from egressweave.validation import _make_validated_egress_url
 
 _REPOSITORY_ROOT = Path(__file__).resolve().parents[1]
+_AUTHORITY_SCHEMA = {
+    "type": "string",
+    "minLength": 3,
+    "maxLength": 259,
+    "pattern": (
+        r"^(?=.{1,253}:)(?![0-9.]+:)(?!0(?:\.)*x[a-z0-9.-]*:)"
+        r"(?:[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?)"
+        r"(?:\.(?:[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?))*:"
+        r"(?:[1-9]|[1-9][0-9]{1,3}|[1-5][0-9]{4}|6[0-4][0-9]{3}|"
+        r"65[0-4][0-9]{2}|655[0-2][0-9]|6553[0-5])$"
+    ),
+}
 _METHOD_ITEM_SCHEMA = {
     "type": "string",
     "pattern": "^[!#$%&'*+.^_`|~0-9A-Z-]+$",
@@ -58,7 +70,7 @@ def test_packaged_schema_matches_protected_main_runtime_shape() -> None:
     assert properties["schema_version"] == {
         "const": egressweave.DECISION_EVIDENCE_SCHEMA_VERSION
     }
-    assert properties["authority"] == {"type": "string", "minLength": 1}
+    assert properties["authority"] == _AUTHORITY_SCHEMA
     assert properties["allowed_methods"] == {
         "type": "array",
         "uniqueItems": True,
@@ -137,7 +149,7 @@ def test_schema_loader_returns_detached_data_on_every_call() -> None:
     second = _load_schema()
     second_properties = second["properties"]
     assert isinstance(second_properties, dict)
-    assert second_properties["authority"] == {"type": "string", "minLength": 1}
+    assert second_properties["authority"] == _AUTHORITY_SCHEMA
 
 
 def test_schema_is_a_packaged_utf8_json_resource() -> None: