diff --git a/.trinity/seals/src_port::trios::crates::trios-chat::rings::CR-CHAT-07::src::cover_traffic_replay_detection_guard.json b/.trinity/seals/src_port::trios::crates::trios-chat::rings::CR-CHAT-07::src::cover_traffic_replay_detection_guard.json
new file mode 100644
index 0000000000..c30c2bb8f1
--- /dev/null
+++ b/.trinity/seals/src_port::trios::crates::trios-chat::rings::CR-CHAT-07::src::cover_traffic_replay_detection_guard.json
@@ -0,0 +1,28 @@
+{
+  "built_by": "t27c-bootstrap@0.5.2+01d0a635f",
+  "closure": [],
+  "config": "gen=c,rust,verilog,zig;tests=zig",
+  "gen_hash_c": "sha256:5d163c948bcbd1bf56d800662594f481fcfb25c3b88fab43b58b185a21ae5f67",
+  "gen_hash_rust": "sha256:0431e36cfd9545d88a4cae54f41ec5781b314195ab9a3e5f4bddd7c16c09452d",
+  "gen_hash_verilog": "sha256:7d21d6225202df08c904c41746d605beade8fab25cbc04687146efcb3b12a28e",
+  "gen_hash_zig": "sha256:5e22547ca28a10b4eb0b16eb09385d6db7b59bf2cbf107384192a8ae6b47f67f",
+  "module": "port::trios::crates::trios-chat::rings::CR-CHAT-07::src::cover_traffic_replay_detection_guard",
+  "ring": 12,
+  "seal_schema": 2,
+  "sealed_at": "2026-10-17T03:02:40Z",
+  "sealed_by": "t27c-bootstrap@0.5.2",
+  "spec_hash": "sha256:5f8bdbea4ad59f4e450b604c20ee40c98ad8bc78b1c192f33ff01acce365f695",
+  "spec_path": "specs/port/trios/crates/trios-chat/rings/CR-CHAT-07/src/cover_traffic_replay_detection_guard.t27",
+  "tests": {
+    "failed": 0,
+    "failing": [],
+    "forced": false,
+    "passed": 12,
+    "total": 12,
+    "vacuous": 0
+  },
+  "toolchain": {
+    "test_runner": "sha256:1982ae948e24d00c5d221ccec12dfce1eb01204b53e37b0f857f93b16d64629d",
+    "zig": "0.16.0"
+  }
+}
\ No newline at end of file
diff --git a/docs/reports/t27b_expectations.json b/docs/reports/t27b_expectations.json
index c041cbab56..b7bf47dfe1 100644
--- a/docs/reports/t27b_expectations.json
+++ b/docs/reports/t27b_expectations.json
@@ -855,6 +855,7 @@
   {"path": "specs/port/trios/crates/trios-chat/rings/CR-CHAT-03/src/unmerged_leaves_bound_guard.t27", "t27b": "pass"},
   {"path": "specs/port/trios/crates/trios-chat/rings/CR-CHAT-05/src/envelope_size_distribution_uniformity.t27", "t27b": "pass"},
   {"path": "specs/port/trios/crates/trios-chat/rings/CR-CHAT-07/src/cover_decoy_ratio_governor.t27", "t27b": "pass"},
+  {"path": "specs/port/trios/crates/trios-chat/rings/CR-CHAT-07/src/cover_traffic_replay_detection_guard.t27", "t27b": "pass"},
   {"path": "specs/port/trios/crates/trios-chat/rings/CR-CHAT-LAWS/src/lib.t27", "t27b": "pass"},
   {"path": "specs/port/trios/crates/trios-cli/src/cmd/agent.t27", "t27b": "pass"},
   {"path": "specs/port/trios/crates/trios-cli/src/cmd/commit.t27", "t27b": "pass"},
diff --git a/specs/port/trios/crates/trios-chat/rings/CR-CHAT-07/src/cover_traffic_replay_detection_guard.t27 b/specs/port/trios/crates/trios-chat/rings/CR-CHAT-07/src/cover_traffic_replay_detection_guard.t27
new file mode 100644
index 0000000000..f2e64b4d31
--- /dev/null
+++ b/specs/port/trios/crates/trios-chat/rings/CR-CHAT-07/src/cover_traffic_replay_detection_guard.t27
@@ -0,0 +1,315 @@
+module port::trios::crates::trios-chat::rings::CR-CHAT-07::src::cover_traffic_replay_detection_guard;
+
+// Port of gHashTag/trios crates/trios-chat/rings/CR-CHAT-07/src/cover_traffic_replay_detection_guard.rs
+// (CR-CHAT-07 - Cover traffic replay detection guard, Wave-113
+// Lane A, R-CHAT-10).
+//
+// Cover patterns must not repeat: a repeating pattern hands the
+// adversary a database match that names cover epochs, patterns
+// that repeat against no known schedule flag as real, and
+// cross-window matches reveal the schedule's period. The
+// rules, in the original's order: the batch ceiling, then per
+// window the zero-index probe, the zero-hash probe, the
+// emission floor, the strictly-increasing index and the
+// repeated-hash scan.
+//
+// The original returns Result<(), CoverReplayError>. This port
+// carries the verdict as a named struct (owner decision D5): Ok
+// first, then the six variants in the original's declaration
+// order - DuplicatePattern, NotIncreasing, ZeroIndex, ZeroHash,
+// BelowMin, TooMany - with every payload field: idx for the
+// zero and duplicate rules, idx with prev and current for the
+// monotonic break, idx with count and min for the floor, and
+// got with max for the ceiling.
+//
+// The BTreeSet dedup becomes a scan over the windows already
+// visited; the hashes stay the fixed [32]u8 form.
+
+// Minimum emissions per window.
+pub const CTRD_MIN_EMISSIONS: usize = 10;
+
+// Maximum windows per batch.
+pub const CTRD_MAX_WINDOWS: usize = 256;
+
+// Pattern hash length.
+pub const CTRD_HASH_LEN: usize = 32;
+
+// A cover traffic window pattern.
+pub struct CoverWindow {
+    index: u64,
+    pattern_hash: [32]u8,
+    emission_count: usize,
+}
+
+// Verdict codes: Ok(()) and CoverReplayError's variants, in declaration order.
+pub enum CoverReplayCode {
+    Ok,
+    DuplicatePattern,
+    NotIncreasing,
+    ZeroIndex,
+    ZeroHash,
+    BelowMin,
+    TooMany,
+}
+
+// The verdict of the replay validation, with every error payload
+// field.
+pub struct CoverReplayVerdict {
+    code: CoverReplayCode,
+    idx: usize,
+    got: usize,
+    bound: usize,
+    prev: u64,
+    current: u64,
+}
+
+// Whole-form equality over the fixed thirty-two hash bytes.
+pub fn hashes_equal(a: [32]u8, b: [32]u8) -> bool {
+    for i in 0..32 {
+        if (a[i] != b[i]) {
+            return false;
+        }
+    }
+    return true;
+}
+
+// The all-zero hash - the original's [0u8; 32] probe.
+pub fn hash_zero(h: [32]u8) -> bool {
+    for i in 0..32 {
+        if (h[i] != 0) {
+            return false;
+        }
+    }
+    return true;
+}
+
+// Whether window i repeats an earlier hash - the original's
+// BTreeSet insert probe, answered by a scan.
+pub fn hash_seen_before(windows: []const CoverWindow, i: usize) -> bool {
+    for j in 0..i {
+        if (hashes_equal(windows[j].pattern_hash, windows[i].pattern_hash)) {
+            return true;
+        }
+    }
+    return false;
+}
+
+// [VERIFIED] Validate cover traffic replay detection. Returns
+// Ok only when every rule holds, checked in the original's
+// order: the batch ceiling, then per window the zero index,
+// the zero hash, the emission floor, the strictly-increasing
+// index and the repeated hash.
+pub fn validate_cover_replay(windows: []const CoverWindow) -> CoverReplayVerdict {
+    if (windows.len > CTRD_MAX_WINDOWS) {
+        return CoverReplayVerdict { code: CoverReplayCode.TooMany, idx: 0, got: windows.len, bound: CTRD_MAX_WINDOWS, prev: 0, current: 0, };
+    }
+    var prev: u64 = 0;
+    for i in 0..windows.len {
+        if (windows[i].index == 0) {
+            return CoverReplayVerdict { code: CoverReplayCode.ZeroIndex, idx: i, got: 0, bound: 0, prev: 0, current: 0, };
+        }
+        if (hash_zero(windows[i].pattern_hash)) {
+            return CoverReplayVerdict { code: CoverReplayCode.ZeroHash, idx: i, got: 0, bound: 0, prev: 0, current: 0, };
+        }
+        if (windows[i].emission_count < CTRD_MIN_EMISSIONS) {
+            return CoverReplayVerdict { code: CoverReplayCode.BelowMin, idx: i, got: windows[i].emission_count, bound: CTRD_MIN_EMISSIONS, prev: 0, current: 0, };
+        }
+        if (i > 0) {
+            if (windows[i].index <= prev) {
+                return CoverReplayVerdict { code: CoverReplayCode.NotIncreasing, idx: i, got: 0, bound: 0, prev: prev, current: windows[i].index, };
+            }
+        }
+        if (hash_seen_before(windows, i)) {
+            return CoverReplayVerdict { code: CoverReplayCode.DuplicatePattern, idx: i, got: 0, bound: 0, prev: 0, current: 0, };
+        }
+        prev = windows[i].index;
+    }
+    return CoverReplayVerdict { code: CoverReplayCode.Ok, idx: 0, got: 0, bound: 0, prev: 0, current: 0, };
+}
+
+// The pattern hashes of the fixtures, one byte repeated
+// thirty-two times - the original's hash(byte) helper, entry by
+// entry.
+pub const HASH_01: [32]u8 = [32]u8{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,};
+pub const HASH_02: [32]u8 = [32]u8{2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,};
+pub const HASH_03: [32]u8 = [32]u8{3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,};
+pub const HASH_AA: [32]u8 = [32]u8{170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170,};
+pub const ZERO_HASH32: [32]u8 = [32]u8{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,};
+
+// The leading hash bytes of the too-many fixture: the
+// original's (i as u8).wrapping_add(1) walk over 0..=256.
+pub const CTRD_FLOOD_257: [257]u8 = [257]u8{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255, 0, 1};
+
+// **CTRD-01** - a duplicate pattern rejected: the second window
+// repeats the first's hash.
+test ctrd_01_duplicate_rejected {
+    const ws: [2]CoverWindow = [2]CoverWindow{
+        CoverWindow { index: 1, pattern_hash: HASH_AA, emission_count: 20, },
+        CoverWindow { index: 2, pattern_hash: HASH_AA, emission_count: 25, },
+    };
+    const v = validate_cover_replay(&ws);
+    assert(v.code == CoverReplayCode.DuplicatePattern);
+    assert(v.idx == 1);
+}
+
+// **CTRD-02** - a non-increasing index rejected: three after
+// five.
+test ctrd_02_not_increasing_rejected {
+    const ws: [2]CoverWindow = [2]CoverWindow{
+        CoverWindow { index: 5, pattern_hash: HASH_01, emission_count: 20, },
+        CoverWindow { index: 3, pattern_hash: HASH_02, emission_count: 20, },
+    };
+    const v = validate_cover_replay(&ws);
+    assert(v.code == CoverReplayCode.NotIncreasing);
+    assert(v.idx == 1);
+    assert(v.prev == 5);
+    assert(v.current == 3);
+}
+
+// **CTRD-03** - the zero index rejected.
+test ctrd_03_zero_index_rejected {
+    const ws: [1]CoverWindow = [1]CoverWindow{
+        CoverWindow { index: 0, pattern_hash: HASH_01, emission_count: 20, },
+    };
+    const v = validate_cover_replay(&ws);
+    assert(v.code == CoverReplayCode.ZeroIndex);
+    assert(v.idx == 0);
+}
+
+// **CTRD-04** - the zero hash rejected.
+test ctrd_04_zero_hash_rejected {
+    const ws: [1]CoverWindow = [1]CoverWindow{
+        CoverWindow { index: 1, pattern_hash: ZERO_HASH32, emission_count: 20, },
+    };
+    const v = validate_cover_replay(&ws);
+    assert(v.code == CoverReplayCode.ZeroHash);
+    assert(v.idx == 0);
+}
+
+// **CTRD-05** - below the emission floor rejected: five of a
+// required ten.
+test ctrd_05_below_min_rejected {
+    const ws: [1]CoverWindow = [1]CoverWindow{
+        CoverWindow { index: 1, pattern_hash: HASH_01, emission_count: 5, },
+    };
+    const v = validate_cover_replay(&ws);
+    assert(v.code == CoverReplayCode.BelowMin);
+    assert(v.idx == 0);
+    assert(v.got == 5);
+    assert(v.bound == 10);
+}
+
+// **CTRD-06** - too many rejected: 257 windows of a maximum 256,
+// built in a loop like the original's, the indexes walking one
+// upward and the hashes carrying the wrapped walk bytes. The
+// batch rule fires before any window is examined.
+test ctrd_06_too_many_rejected {
+    var ws: [257]CoverWindow;
+    for i in 0..257 {
+        var h: [32]u8 = [32]u8{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,};
+        h[0] = CTRD_FLOOD_257[i];
+        ws[i] = CoverWindow { index: @as(u64, i) + 1, pattern_hash: h, emission_count: 20, };
+    }
+    const v = validate_cover_replay(&ws);
+    assert(v.code == CoverReplayCode.TooMany);
+    assert(v.got == 257);
+    assert(v.bound == 256);
+}
+
+// **CTRD-07** - the valid batch accepted: three windows, three
+// hashes.
+test ctrd_07_valid_accepted {
+    const ws: [3]CoverWindow = [3]CoverWindow{
+        CoverWindow { index: 1, pattern_hash: HASH_01, emission_count: 20, },
+        CoverWindow { index: 2, pattern_hash: HASH_02, emission_count: 25, },
+        CoverWindow { index: 3, pattern_hash: HASH_03, emission_count: 22, },
+    };
+    const v = validate_cover_replay(&ws);
+    assert(v.code == CoverReplayCode.Ok);
+}
+
+// **CTRD-08** - an empty batch accepted.
+test ctrd_08_empty_accepted {
+    const ws: [0]CoverWindow = [0]CoverWindow{};
+    const v = validate_cover_replay(&ws);
+    assert(v.code == CoverReplayCode.Ok);
+}
+
+// **CTRD-09** - a single window accepted.
+test ctrd_09_single_accepted {
+    const ws: [1]CoverWindow = [1]CoverWindow{
+        CoverWindow { index: 1, pattern_hash: HASH_01, emission_count: 20, },
+    };
+    const v = validate_cover_replay(&ws);
+    assert(v.code == CoverReplayCode.Ok);
+}
+
+// **CTRD-10** - the boundary emission count accepted: exactly
+// ten.
+test ctrd_10_boundary_accepted {
+    const ws: [1]CoverWindow = [1]CoverWindow{
+        CoverWindow { index: 1, pattern_hash: HASH_01, emission_count: 10, },
+    };
+    const v = validate_cover_replay(&ws);
+    assert(v.code == CoverReplayCode.Ok);
+}
+
+// The three helpers have direct tests (coverage: Untested 0).
+test ctrd_helpers_answer {
+    assert(hashes_equal(HASH_01, HASH_01));
+    assert(!hashes_equal(HASH_01, HASH_02));
+    assert(hash_zero(ZERO_HASH32));
+    assert(!hash_zero(HASH_01));
+    const three: [3]CoverWindow = [3]CoverWindow{
+        CoverWindow { index: 1, pattern_hash: HASH_01, emission_count: 20, },
+        CoverWindow { index: 2, pattern_hash: HASH_02, emission_count: 20, },
+        CoverWindow { index: 3, pattern_hash: HASH_01, emission_count: 20, },
+    };
+    assert(!hash_seen_before(&three, 0));
+    assert(!hash_seen_before(&three, 1));
+    assert(hash_seen_before(&three, 2));
+}
+
+// Rule order is the original's: the zero index before the zero
+// hash, the zero hash before the emission floor, the floor
+// before the monotonicity, and the monotonicity before the
+// repeated hash - with both violations on one window.
+test rule_order_matches_original {
+    const zero_both: [1]CoverWindow = [1]CoverWindow{
+        CoverWindow { index: 0, pattern_hash: ZERO_HASH32, emission_count: 5, },
+    };
+    const v1 = validate_cover_replay(&zero_both);
+    assert(v1.code == CoverReplayCode.ZeroIndex);
+    assert(v1.idx == 0);
+
+    const zero_hash_few: [1]CoverWindow = [1]CoverWindow{
+        CoverWindow { index: 1, pattern_hash: ZERO_HASH32, emission_count: 5, },
+    };
+    const v2 = validate_cover_replay(&zero_hash_few);
+    assert(v2.code == CoverReplayCode.ZeroHash);
+    assert(v2.idx == 0);
+
+    const few_backstep: [2]CoverWindow = [2]CoverWindow{
+        CoverWindow { index: 5, pattern_hash: HASH_01, emission_count: 20, },
+        CoverWindow { index: 3, pattern_hash: HASH_02, emission_count: 5, },
+    };
+    const v3 = validate_cover_replay(&few_backstep);
+    assert(v3.code == CoverReplayCode.BelowMin);
+    assert(v3.idx == 1);
+
+    const backstep_dup: [2]CoverWindow = [2]CoverWindow{
+        CoverWindow { index: 5, pattern_hash: HASH_01, emission_count: 20, },
+        CoverWindow { index: 3, pattern_hash: HASH_01, emission_count: 20, },
+    };
+    const v4 = validate_cover_replay(&backstep_dup);
+    assert(v4.code == CoverReplayCode.NotIncreasing);
+    assert(v4.idx == 1);
+
+    const dup_only: [2]CoverWindow = [2]CoverWindow{
+        CoverWindow { index: 5, pattern_hash: HASH_01, emission_count: 20, },
+        CoverWindow { index: 6, pattern_hash: HASH_01, emission_count: 20, },
+    };
+    const v5 = validate_cover_replay(&dup_only);
+    assert(v5.code == CoverReplayCode.DuplicatePattern);
+    assert(v5.idx == 1);
+}