diff --git a/.trinity/seals/claw_ClawCheckLatest.json b/.trinity/seals/claw_ClawCheckLatest.json
index c271c4ad63..57233ca013 100644
--- a/.trinity/seals/claw_ClawCheckLatest.json
+++ b/.trinity/seals/claw_ClawCheckLatest.json
@@ -7,7 +7,7 @@
     },
     {
       "spec": "specs/claw/queue_cost.t27",
-      "spec_hash": "sha256:16789d92d878e85e3d02e56a9be4bffe0b565b5c14c270f79ddaedc6d6911f7e"
+      "spec_hash": "sha256:9e5cd5e46f28ac23cf36a555a4f416bcabb8858d48fdd79afaa4743aa33e4106"
     },
     {
       "spec": "specs/claw/text.t27",
@@ -22,7 +22,7 @@
   "module": "ClawCheckLatest",
   "ring": 12,
   "seal_schema": 2,
-  "sealed_at": "2026-10-19T00:52:44Z",
+  "sealed_at": "2026-10-19T01:46:13Z",
   "sealed_by": "t27c-bootstrap@0.5.2",
   "spec_hash": "sha256:2de14a373379d1a5acc19fffeb4123c951dc6f36caffb883fb5a8a406be65d58",
   "spec_path": "specs/claw/check_latest.t27",
diff --git a/.trinity/seals/claw_ClawCheckState.json b/.trinity/seals/claw_ClawCheckState.json
index 4e4d6d73f5..e74daa97d6 100644
--- a/.trinity/seals/claw_ClawCheckState.json
+++ b/.trinity/seals/claw_ClawCheckState.json
@@ -3,7 +3,7 @@
   "closure": [
     {
       "spec": "specs/claw/queue_cost.t27",
-      "spec_hash": "sha256:16789d92d878e85e3d02e56a9be4bffe0b565b5c14c270f79ddaedc6d6911f7e"
+      "spec_hash": "sha256:9e5cd5e46f28ac23cf36a555a4f416bcabb8858d48fdd79afaa4743aa33e4106"
     },
     {
       "spec": "specs/claw/text.t27",
@@ -18,7 +18,7 @@
   "module": "ClawCheckState",
   "ring": 12,
   "seal_schema": 2,
-  "sealed_at": "2026-10-19T00:52:41Z",
+  "sealed_at": "2026-10-19T01:46:14Z",
   "sealed_by": "t27c-bootstrap@0.5.2",
   "spec_hash": "sha256:bd3aa36047755e7b95144ca4bbdb760aa971ceeb94b7e0728dd4db49b842ead6",
   "spec_path": "specs/claw/check_state.t27",
diff --git a/.trinity/seals/claw_ClawMergeLane.json b/.trinity/seals/claw_ClawMergeLane.json
index 6f9f00dc27..d8419e2bd3 100644
--- a/.trinity/seals/claw_ClawMergeLane.json
+++ b/.trinity/seals/claw_ClawMergeLane.json
@@ -7,7 +7,7 @@
     },
     {
       "spec": "specs/claw/queue_cost.t27",
-      "spec_hash": "sha256:16789d92d878e85e3d02e56a9be4bffe0b565b5c14c270f79ddaedc6d6911f7e"
+      "spec_hash": "sha256:9e5cd5e46f28ac23cf36a555a4f416bcabb8858d48fdd79afaa4743aa33e4106"
     },
     {
       "spec": "specs/claw/text.t27",
@@ -22,7 +22,7 @@
   "module": "ClawMergeLane",
   "ring": 12,
   "seal_schema": 2,
-  "sealed_at": "2026-10-19T00:52:43Z",
+  "sealed_at": "2026-10-19T01:46:14Z",
   "sealed_by": "t27c-bootstrap@0.5.2",
   "spec_hash": "sha256:3ebb5dbd29a60d877506ea11512d091d043a223e441d1668d4be9cfbf027602c",
   "spec_path": "specs/claw/merge_lane.t27",
diff --git a/.trinity/seals/claw_ClawQueueCost.json b/.trinity/seals/claw_ClawQueueCost.json
index ee2fc4f904..6f1ea1b17f 100644
--- a/.trinity/seals/claw_ClawQueueCost.json
+++ b/.trinity/seals/claw_ClawQueueCost.json
@@ -7,23 +7,23 @@
     }
   ],
   "config": "gen=c,rust,verilog,zig;tests=zig",
-  "gen_hash_c": "sha256:b2e8310b04602772ae4c26f782651814781f800ad546dda08aad328eae380a7d",
-  "gen_hash_rust": "sha256:2139d76ca0e026b76e2d306c1fb4ace20241826dc9faa24b78c85672732afdf3",
-  "gen_hash_verilog": "sha256:d444d186653d294157ee175cafc704c5dbae2039d327fe5861bb372f67ec2cbd",
-  "gen_hash_zig": "sha256:23901c784d363d5d67ac4c8d2ed4e8e864fc7dd984a4aa49633222e5b66a4eb4",
+  "gen_hash_c": "sha256:5518a451c87946600d44194170093905e6bbcdb068d7a7ca957d5a9a5df217bf",
+  "gen_hash_rust": "sha256:51e28ad80b5d4afa5439232d210d72e80847bb44430420bc92e577c370fb6395",
+  "gen_hash_verilog": "sha256:aee185a40054556ddea7f7941154a7ad32d9f3c6fe5d6635b6cf7b0fa071a115",
+  "gen_hash_zig": "sha256:ab90f1efa8bea0484a59a885d06671bf89cdf4e377b87a8c456f4b9f152d5403",
   "module": "ClawQueueCost",
   "ring": 12,
   "seal_schema": 2,
-  "sealed_at": "2026-10-19T00:13:56Z",
+  "sealed_at": "2026-10-19T01:46:13Z",
   "sealed_by": "t27c-bootstrap@0.5.2",
-  "spec_hash": "sha256:16789d92d878e85e3d02e56a9be4bffe0b565b5c14c270f79ddaedc6d6911f7e",
+  "spec_hash": "sha256:9e5cd5e46f28ac23cf36a555a4f416bcabb8858d48fdd79afaa4743aa33e4106",
   "spec_path": "specs/claw/queue_cost.t27",
   "tests": {
     "failed": 0,
     "failing": [],
     "forced": false,
-    "passed": 13,
-    "total": 13,
+    "passed": 23,
+    "total": 23,
     "vacuous": 0
   },
   "toolchain": {
diff --git a/.trinity/seals/claw_ClawRequiredRed.json b/.trinity/seals/claw_ClawRequiredRed.json
index 7c7be57c53..12769a8ab4 100644
--- a/.trinity/seals/claw_ClawRequiredRed.json
+++ b/.trinity/seals/claw_ClawRequiredRed.json
@@ -11,7 +11,7 @@
     },
     {
       "spec": "specs/claw/queue_cost.t27",
-      "spec_hash": "sha256:16789d92d878e85e3d02e56a9be4bffe0b565b5c14c270f79ddaedc6d6911f7e"
+      "spec_hash": "sha256:9e5cd5e46f28ac23cf36a555a4f416bcabb8858d48fdd79afaa4743aa33e4106"
     },
     {
       "spec": "specs/claw/text.t27",
@@ -19,23 +19,23 @@
     }
   ],
   "config": "gen=c,rust,verilog,zig;tests=zig",
-  "gen_hash_c": "sha256:c717b993844f5ea9e505638b7dfae7c8e471b554d6b2a210ab05576aa54ed8f3",
-  "gen_hash_rust": "sha256:70d7923ef8e74fc126f6316f1fe4937e39c40dbe2fbd9e9e2561c71cda0c194a",
-  "gen_hash_verilog": "sha256:9fbeec197b7b09796269f91e84dd050683379b0e82cc9215afb1bdf4b128134c",
-  "gen_hash_zig": "sha256:fa1b7c3383c64c7c111598dc9dca071f2208c152fd51a55c64733d422d2b83c3",
+  "gen_hash_c": "sha256:f08559d0d75f0cb4b6c76c9dcc6c60751228158ac07fc9fd7dd211c6ab57d01f",
+  "gen_hash_rust": "sha256:36b9e6e53cffb74f56be7db41a3997fb8ccb5f8d66b5212284ac3465e2e94409",
+  "gen_hash_verilog": "sha256:82a838c971f8e40658108e73e64e534618ec7198255ff4382178c5105bbc17bf",
+  "gen_hash_zig": "sha256:56a4d64802576e2532df7cb016086e500697a863d90a4884f314f1bd22dd57ef",
   "module": "ClawRequiredRed",
   "ring": 12,
   "seal_schema": 2,
-  "sealed_at": "2026-10-19T00:52:44Z",
+  "sealed_at": "2026-10-19T01:47:29Z",
   "sealed_by": "t27c-bootstrap@0.5.2",
-  "spec_hash": "sha256:ad8660400d420444a1a3c8858866b4cf7447f60027e27e1bb333a9463e1decea",
+  "spec_hash": "sha256:585ddbdea9f98d3b4a45700e47cf6706528339874d1adfce796828b6804b5866",
   "spec_path": "specs/claw/required_red.t27",
   "tests": {
     "failed": 0,
     "failing": [],
     "forced": false,
-    "passed": 9,
-    "total": 9,
+    "passed": 11,
+    "total": 11,
     "vacuous": 0
   },
   "toolchain": {
diff --git a/.trinity/seals/claw_ClawShapeRace.json b/.trinity/seals/claw_ClawShapeRace.json
index c84f84a693..4effb78044 100644
--- a/.trinity/seals/claw_ClawShapeRace.json
+++ b/.trinity/seals/claw_ClawShapeRace.json
@@ -3,7 +3,7 @@
   "closure": [
     {
       "spec": "specs/claw/queue_cost.t27",
-      "spec_hash": "sha256:16789d92d878e85e3d02e56a9be4bffe0b565b5c14c270f79ddaedc6d6911f7e"
+      "spec_hash": "sha256:9e5cd5e46f28ac23cf36a555a4f416bcabb8858d48fdd79afaa4743aa33e4106"
     },
     {
       "spec": "specs/claw/text.t27",
@@ -11,23 +11,23 @@
     }
   ],
   "config": "gen=c,rust,verilog,zig;tests=zig",
-  "gen_hash_c": "sha256:3624f66398f6a65a3ff3e9b6c09c19bac643bb3cff3cd04142e9732ab608935a",
-  "gen_hash_rust": "sha256:198fd96b5a9645304cb54ee2afef389dc4d24efc6599e18d93bc474306fe74e6",
-  "gen_hash_verilog": "sha256:4aa8ecfad528d16f9d3dac176d76f8c8d5be9121ce84beb33e29e8140422ba06",
-  "gen_hash_zig": "sha256:a81683ac1fc254972ee0e9c787a3f1c08a4948791ec8d08dec8fde4020c67ee1",
+  "gen_hash_c": "sha256:976643ecc232da66baaf7c2250f4fcca8da5fe6bc3727d432e4c6625ff4bcae1",
+  "gen_hash_rust": "sha256:d999644b88cdf157cead4084cc11c06e80041c4fefeb0e7283f8b6030bff36f4",
+  "gen_hash_verilog": "sha256:95078930e8a7aa7409e18001a2f90a2574309cf773090940f09d4c0386e071c2",
+  "gen_hash_zig": "sha256:d82360d4cd406e5cfcb5ee7c999fe4c1d9da338bf692bd8f1f2bd88e8450014a",
   "module": "ClawShapeRace",
   "ring": 12,
   "seal_schema": 2,
-  "sealed_at": "2026-10-19T00:13:59Z",
+  "sealed_at": "2026-10-19T01:56:02Z",
   "sealed_by": "t27c-bootstrap@0.5.2",
-  "spec_hash": "sha256:c8a0cdfe7dc74400419616f8b6b22e3b3291fba6dd8d8def1b5c9952fce978ec",
+  "spec_hash": "sha256:8fa56fbbb52fde151ed84c59bfc8d279c8a3b48dc82713b6405824a738bf56c5",
   "spec_path": "specs/claw/shape_race.t27",
   "tests": {
     "failed": 0,
     "failing": [],
     "forced": false,
-    "passed": 16,
-    "total": 16,
+    "passed": 19,
+    "total": 19,
     "vacuous": 0
   },
   "toolchain": {
diff --git a/specs/claw/queue_cost.t27 b/specs/claw/queue_cost.t27
index 6459b96a15..db0da676d6 100644
--- a/specs/claw/queue_cost.t27
+++ b/specs/claw/queue_cost.t27
@@ -546,3 +546,116 @@ fn t_has_line(out : []const u8, n : usize, b : u8) -> bool {
     }
     return false;
 }
+
+// The tests below were written against a mutation sweep of this file: each one fails under at
+// least one mutant of the code above that the earlier tests let through.
+
+test t_has_line_finds_a_line_start_and_only_a_line_start {
+    assert t_has_line("H", 1, 'H') == true;
+    assert t_has_line("M\nH", 3, 'H') == true;
+    assert t_has_line("MH\n", 3, 'H') == false;
+    assert t_has_line("M\nH", 2, 'H') == false;
+}
+
+test splitting_into_zero_fields_fails_closed {
+    var f : [4]usize = undefined;
+    assert qc_split("", 0, 0, &f, 0) == false;
+    assert qc_split("a", 0, 1, &f, 0) == false;
+}
+
+test a_sha_is_forty_lowercase_hex_digits_at_the_range_bounds {
+    assert qc_sha_ok("0123456789abcdef0123456789abcdef01234567", 0, 40) == true;
+    assert qc_sha_ok("9999999999ffffffffff00000000000aaaaaaaaa", 0, 40) == true;
+    assert qc_sha_ok("/123456789abcdef0123456789abcdef01234567", 0, 40) == false;
+    assert qc_sha_ok(":123456789abcdef0123456789abcdef01234567", 0, 40) == false;
+    assert qc_sha_ok("`123456789abcdef0123456789abcdef01234567", 0, 40) == false;
+    assert qc_sha_ok("g123456789abcdef0123456789abcdef01234567", 0, 40) == false;
+    assert qc_sha_ok("A123456789abcdef0123456789abcdef01234567", 0, 40) == false;
+}
+
+test negative_control_one_bad_sha_of_two_makes_the_run_unreadable {
+    var r : [256]u8 = undefined;
+    var n : usize = put_str(&r, 256, 0, "pull_request\tOPEN\tfalse\t", 24);
+    n = t_sha(&r, 256, n, 'a');
+    n = put_str(&r, 256, n, "\tabc\npull_request\tOPEN\tfalse\tabc\t", 33);
+    n = t_sha(&r, 256, n, 'a');
+    n = qc_put_byte(&r, 256, n, '\n');
+    var out : [512]u8 = undefined;
+    const d : usize = class_plan(&r, n, &out, 512);
+    assert buf_has(&out, d, " 0 superseded head, ", 20) == true;
+    assert buf_has(&out, d, " 2 unreadable\n", 14) == true;
+}
+
+test a_blank_line_is_not_a_row_in_either_answer {
+    var out : [512]u8 = undefined;
+    var d : usize = cost_plan("a\t60\n\nb\t60\n", 11, &out, 512);
+    assert buf_has(&out, d, " in 2 jobs, 0 unreadable\n", 25) == true;
+    d = class_plan("push\t-\t-\t-\t-\n\npush\t-\t-\t-\t-\n", 27, &out, 512);
+    assert buf_has(&out, d, " 2 other event, 0 unreadable\n", 29) == true;
+}
+
+test exactly_half_the_time_is_named_as_the_lever {
+    var out : [512]u8 = undefined;
+    const d : usize = cost_plan("a\t60\nb\t60\n", 10, &out, 512);
+    assert buf_has(&out, d, "H\ta\t50\n", 7) == true;
+    assert buf_has(&out, d, "one workflow holds 50% of job time", 34) == true;
+}
+
+test a_last_row_without_a_newline_is_still_read {
+    var out : [512]u8 = undefined;
+    const d : usize = cost_plan("w\t120", 5, &out, 512);
+    assert buf_has(&out, d, " in 1 jobs, 0 unreadable\n", 25) == true;
+    assert buf_has(&out, d, "H\tw\t100\n", 8) == true;
+}
+
+test an_answer_that_ends_exactly_at_cap_is_not_written_past_it {
+    var out : [56]u8 = undefined;
+    const d : usize = cost_plan("w\t120\n", 6, &out, 56);
+    assert d > 56;
+    assert out[0] == 'M';
+    assert out[55] == '\n';
+}
+
+test the_row_cap_is_exact_in_both_answers {
+    var r : [53300]u8 = undefined;
+    var out : [512]u8 = undefined;
+    var n : usize = 0;
+    var i : u32 = 0;
+    while (i < 4096) {
+        n = put_str(&r, 53300, n, "a\t1\n", 4);
+        i += 1;
+    }
+    var d : usize = cost_plan(&r, n, &out, 512);
+    assert buf_has(&out, d, " in 4096 jobs, 0 unreadable\n", 28) == true;
+    n = put_str(&r, 53300, n, "a\t1\n", 4);
+    d = cost_plan(&r, n, &out, 512);
+    assert buf_has(&out, d, " in 4096 jobs, 1 unreadable\n", 28) == true;
+    n = t_runs(&r, 53300, 0, C_OTHER, 4097);
+    assert n == 53261;
+    d = class_plan(&r, n, &out, 512);
+    assert buf_has(&out, d, " 4096 other event, 1 unreadable\n", 32) == true;
+}
+
+test negative_control_the_workflow_table_holds_sixty_four_names {
+    var r : [1024]u8 = undefined;
+    var out : [512]u8 = undefined;
+    var n : usize = 0;
+    var i : u32 = 0;
+    while (i < 65) {
+        n = put_count(&r, 1024, n, i);
+        n = put_str(&r, 1024, n, "\t1\n", 3);
+        i += 1;
+    }
+    n = put_str(&r, 1024, n, "0\t1\n", 4);
+    var d : usize = cost_plan(&r, n, &out, 512);
+    assert buf_has(&out, d, " in 65 jobs, 1 unreadable\n", 26) == true;
+    n = 0;
+    i = 0;
+    while (i < 64) {
+        n = put_str(&r, 1024, n, "a\t1\n", 4);
+        i += 1;
+    }
+    n = put_str(&r, 1024, n, "b\t1\n", 4);
+    d = cost_plan(&r, n, &out, 512);
+    assert buf_has(&out, d, " in 65 jobs, 0 unreadable\n", 26) == true;
+}
diff --git a/specs/claw/required_red.t27 b/specs/claw/required_red.t27
index e41f8aee88..f51e7502ac 100644
--- a/specs/claw/required_red.t27
+++ b/specs/claw/required_red.t27
@@ -239,3 +239,35 @@ test a_clipped_plan_still_advances_the_cursor {
     var out : [128]u8 = undefined;
     assert required_plan(&raw, n, &out, 40) == 87;
 }
+
+// The tests below were written against a mutation sweep of this file: each one fails under a
+// mutant of required_counts that the earlier tests let through.
+
+test a_blank_line_is_not_a_row {
+    var raw : [128]u8 = undefined;
+    var x : usize = put_str(&raw, 128, 0, "CI/validate\t11\tCOMPLETED\tSUCCESS\n\n", 34);
+    x = put_str(&raw, 128, x, "Own/own-language\t13\tCOMPLETED\tSUCCESS\n", 38);
+    var st : [5]u32 = undefined;
+    assert required_counts(&raw, x, &st) == 2;
+    assert st[K_PASS] == 2;
+    assert st[K_BAD] == 0;
+    assert required_flag(&raw, x) == RR_FALSE;
+}
+
+test negative_control_the_row_past_the_cap_is_unreadable_and_the_last_one_in_it_is_read {
+    var raw : [40000]u8 = undefined;
+    var st : [5]u32 = undefined;
+    var x : usize = t_rows(&raw, 40000, 0, "Claw/claw-sarif\t14\tCOMPLETED\tSUCCESS\n", 37, 1023);
+    x = put_str(&raw, 40000, x, "CI/validate\t11\tCOMPLETED\tSUCCESS\n", 33);
+    assert required_counts(&raw, x, &st) == 1024;
+    assert st[K_PASS] == 1;
+    assert st[K_BAD] == 0;
+    x = t_rows(&raw, 40000, 0, "Claw/claw-sarif\t14\tCOMPLETED\tSUCCESS\n", 37, 1024);
+    x = put_str(&raw, 40000, x, "CI/validate\t11\tCOMPLETED\tSUCCESS\n", 33);
+    assert x == 37921;
+    assert required_counts(&raw, x, &st) == 1025;
+    assert st[K_PASS] == 0;
+    assert st[K_BAD] == 1;
+    assert st[RR_MISSING] == 4;
+    assert required_flag(&raw, x) == RR_UNKNOWN;
+}
diff --git a/specs/claw/shape_race.t27 b/specs/claw/shape_race.t27
index 1a2033f76f..a66a279190 100644
--- a/specs/claw/shape_race.t27
+++ b/specs/claw/shape_race.t27
@@ -420,3 +420,26 @@ test the_plan_prints_each_reading_its_own_end {
     assert buf_has(&out, w, "ends stuck; live leaves it wrong after 0 runs, ends right\n", 58) == true;
     assert n == 45;
 }
+
+// The tests below were written against a mutation sweep of this file: each one fails under at
+// least one mutant of the code above that the earlier tests let through.
+
+test a_blank_line_is_not_an_event {
+    assert sr_verdict("5\t9\t1\n\n6\t9\t1\n", 13) == SR_CLEAN;
+    var out : [200]u8 = undefined;
+    const w : usize = race_plan("5\t9\t1\n\n6\t9\t1\n", 13, &out, 200);
+    assert buf_has(&out, w, "R\tshape-race: 2 events, 0 cancelled, 0 unreadable;", 50) == true;
+}
+
+test second_zero_is_a_real_second {
+    assert sr_verdict("0\t9\t1\n", 6) == SR_CLEAN;
+    assert t_replay("0\t0\t0\n", 6, false) == 0;
+    assert t_replay("0\t0\t0\n", 6, true) == 0;
+}
+
+test negative_control_jobs_in_the_same_second_replay_in_input_order {
+    // Row 0 closes at 5. Both later jobs run at 50: the failing edit closes again, then the passing
+    // edit, whose old label is row 0's close, reopens. In the other order the issue ends stuck.
+    assert t_replay("1\t5\t0\n10\t50\t0\n20\t50\t1\n", 22, false) == 10;
+    assert t_replay("1\t5\t0\n20\t50\t1\n10\t50\t0\n", 22, false) == 11;
+}