diff --git a/contracts/cultnet/governance/fork-card-vectors.json b/contracts/cultnet/governance/fork-card-vectors.json
index 7701ff02..ea738e85 100644
--- a/contracts/cultnet/governance/fork-card-vectors.json
+++ b/contracts/cultnet/governance/fork-card-vectors.json
@@ -656,6 +656,107 @@
           "options_hash": "7d95fc87d532420611fe415c1def27a3447617bb68235f46e3af130aea361c48"
         },
         "messagePackHex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
+      },
+      {
+        "name": "deciders_at_the_cap_of_64",
+        "message": {
+          "schemaVersion": "gamecult.fork.card.v0",
+          "fork_id": "gamecult-chat:question:slot-mark-consent",
+          "title": "Slot mark consent",
+          "context": "Should a slot mark be shared?",
+          "options": [
+            {
+              "id": "yes",
+              "text": "Share it."
+            },
+            {
+              "id": "no",
+              "text": "Keep it local."
+            }
+          ],
+          "recommendation": "no",
+          "depends": [
+            "gamecult-chat:question:file-zone-audience"
+          ],
+          "leans": null,
+          "flag": null,
+          "raised_in": {
+            "kind": "CutSpec",
+            "id": "cultlib-gaps:cut_spec:cut-slot-tolerance.r4"
+          },
+          "deciders": [
+            "00000001-0000-4000-8000-000000000001",
+            "00000002-0000-4000-8000-000000000002",
+            "00000003-0000-4000-8000-000000000003",
+            "00000004-0000-4000-8000-000000000004",
+            "00000005-0000-4000-8000-000000000005",
+            "00000006-0000-4000-8000-000000000006",
+            "00000007-0000-4000-8000-000000000007",
+            "00000008-0000-4000-8000-000000000008",
+            "00000009-0000-4000-8000-000000000009",
+            "0000000a-0000-4000-8000-00000000000a",
+            "0000000b-0000-4000-8000-00000000000b",
+            "0000000c-0000-4000-8000-00000000000c",
+            "0000000d-0000-4000-8000-00000000000d",
+            "0000000e-0000-4000-8000-00000000000e",
+            "0000000f-0000-4000-8000-00000000000f",
+            "00000010-0000-4000-8000-000000000010",
+            "00000011-0000-4000-8000-000000000011",
+            "00000012-0000-4000-8000-000000000012",
+            "00000013-0000-4000-8000-000000000013",
+            "00000014-0000-4000-8000-000000000014",
+            "00000015-0000-4000-8000-000000000015",
+            "00000016-0000-4000-8000-000000000016",
+            "00000017-0000-4000-8000-000000000017",
+            "00000018-0000-4000-8000-000000000018",
+            "00000019-0000-4000-8000-000000000019",
+            "0000001a-0000-4000-8000-00000000001a",
+            "0000001b-0000-4000-8000-00000000001b",
+            "0000001c-0000-4000-8000-00000000001c",
+            "0000001d-0000-4000-8000-00000000001d",
+            "0000001e-0000-4000-8000-00000000001e",
+            "0000001f-0000-4000-8000-00000000001f",
+            "00000020-0000-4000-8000-000000000020",
+            "00000021-0000-4000-8000-000000000021",
+            "00000022-0000-4000-8000-000000000022",
+            "00000023-0000-4000-8000-000000000023",
+            "00000024-0000-4000-8000-000000000024",
+            "00000025-0000-4000-8000-000000000025",
+            "00000026-0000-4000-8000-000000000026",
+            "00000027-0000-4000-8000-000000000027",
+            "00000028-0000-4000-8000-000000000028",
+            "00000029-0000-4000-8000-000000000029",
+            "0000002a-0000-4000-8000-00000000002a",
+            "0000002b-0000-4000-8000-00000000002b",
+            "0000002c-0000-4000-8000-00000000002c",
+            "0000002d-0000-4000-8000-00000000002d",
+            "0000002e-0000-4000-8000-00000000002e",
+            "0000002f-0000-4000-8000-00000000002f",
+            "00000030-0000-4000-8000-000000000030",
+            "00000031-0000-4000-8000-000000000031",
+            "00000032-0000-4000-8000-000000000032",
+            "00000033-0000-4000-8000-000000000033",
+            "00000034-0000-4000-8000-000000000034",
+            "00000035-0000-4000-8000-000000000035",
+            "00000036-0000-4000-8000-000000000036",
+            "00000037-0000-4000-8000-000000000037",
+            "00000038-0000-4000-8000-000000000038",
+            "00000039-0000-4000-8000-000000000039",
+            "0000003a-0000-4000-8000-00000000003a",
+            "0000003b-0000-4000-8000-00000000003b",
+            "0000003c-0000-4000-8000-00000000003c",
+            "0000003d-0000-4000-8000-00000000003d",
+            "0000003e-0000-4000-8000-00000000003e",
+            "0000003f-0000-4000-8000-00000000003f",
+            "00000040-0000-4000-8000-000000000040"
+          ],
+          "status": "open",
+          "ruling": null,
+          "ruled_from": [],
+          "order": 3,
+          "options_hash": "7d95fc87d532420611fe415c1def27a3447617bb68235f46e3af130aea361c48"
+        },
+        "messagePackHex": "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"
       }
     ],
     "invalid": [
@@ -1389,6 +1490,108 @@
           "order": 3,
           "options_hash": "14b8ffbdb61106dbc06f69f3fc8e2072af7a205d766e4cc040e89733013d54dc"
         }
+      },
+      {
+        "name": "deciders_65",
+        "why": "deciders holds at most 64 (Huginn's bound)",
+        "message": {
+          "schemaVersion": "gamecult.fork.card.v0",
+          "fork_id": "gamecult-chat:question:slot-mark-consent",
+          "title": "Slot mark consent",
+          "context": "Should a slot mark be shared?",
+          "options": [
+            {
+              "id": "yes",
+              "text": "Share it."
+            },
+            {
+              "id": "no",
+              "text": "Keep it local."
+            }
+          ],
+          "recommendation": "no",
+          "depends": [
+            "gamecult-chat:question:file-zone-audience"
+          ],
+          "leans": null,
+          "flag": null,
+          "raised_in": {
+            "kind": "CutSpec",
+            "id": "cultlib-gaps:cut_spec:cut-slot-tolerance.r4"
+          },
+          "deciders": [
+            "00000001-0000-4000-8000-000000000001",
+            "00000002-0000-4000-8000-000000000002",
+            "00000003-0000-4000-8000-000000000003",
+            "00000004-0000-4000-8000-000000000004",
+            "00000005-0000-4000-8000-000000000005",
+            "00000006-0000-4000-8000-000000000006",
+            "00000007-0000-4000-8000-000000000007",
+            "00000008-0000-4000-8000-000000000008",
+            "00000009-0000-4000-8000-000000000009",
+            "0000000a-0000-4000-8000-00000000000a",
+            "0000000b-0000-4000-8000-00000000000b",
+            "0000000c-0000-4000-8000-00000000000c",
+            "0000000d-0000-4000-8000-00000000000d",
+            "0000000e-0000-4000-8000-00000000000e",
+            "0000000f-0000-4000-8000-00000000000f",
+            "00000010-0000-4000-8000-000000000010",
+            "00000011-0000-4000-8000-000000000011",
+            "00000012-0000-4000-8000-000000000012",
+            "00000013-0000-4000-8000-000000000013",
+            "00000014-0000-4000-8000-000000000014",
+            "00000015-0000-4000-8000-000000000015",
+            "00000016-0000-4000-8000-000000000016",
+            "00000017-0000-4000-8000-000000000017",
+            "00000018-0000-4000-8000-000000000018",
+            "00000019-0000-4000-8000-000000000019",
+            "0000001a-0000-4000-8000-00000000001a",
+            "0000001b-0000-4000-8000-00000000001b",
+            "0000001c-0000-4000-8000-00000000001c",
+            "0000001d-0000-4000-8000-00000000001d",
+            "0000001e-0000-4000-8000-00000000001e",
+            "0000001f-0000-4000-8000-00000000001f",
+            "00000020-0000-4000-8000-000000000020",
+            "00000021-0000-4000-8000-000000000021",
+            "00000022-0000-4000-8000-000000000022",
+            "00000023-0000-4000-8000-000000000023",
+            "00000024-0000-4000-8000-000000000024",
+            "00000025-0000-4000-8000-000000000025",
+            "00000026-0000-4000-8000-000000000026",
+            "00000027-0000-4000-8000-000000000027",
+            "00000028-0000-4000-8000-000000000028",
+            "00000029-0000-4000-8000-000000000029",
+            "0000002a-0000-4000-8000-00000000002a",
+            "0000002b-0000-4000-8000-00000000002b",
+            "0000002c-0000-4000-8000-00000000002c",
+            "0000002d-0000-4000-8000-00000000002d",
+            "0000002e-0000-4000-8000-00000000002e",
+            "0000002f-0000-4000-8000-00000000002f",
+            "00000030-0000-4000-8000-000000000030",
+            "00000031-0000-4000-8000-000000000031",
+            "00000032-0000-4000-8000-000000000032",
+            "00000033-0000-4000-8000-000000000033",
+            "00000034-0000-4000-8000-000000000034",
+            "00000035-0000-4000-8000-000000000035",
+            "00000036-0000-4000-8000-000000000036",
+            "00000037-0000-4000-8000-000000000037",
+            "00000038-0000-4000-8000-000000000038",
+            "00000039-0000-4000-8000-000000000039",
+            "0000003a-0000-4000-8000-00000000003a",
+            "0000003b-0000-4000-8000-00000000003b",
+            "0000003c-0000-4000-8000-00000000003c",
+            "0000003d-0000-4000-8000-00000000003d",
+            "0000003e-0000-4000-8000-00000000003e",
+            "0000003f-0000-4000-8000-00000000003f",
+            "00000040-0000-4000-8000-000000000040",
+            "00000041-0000-4000-8000-000000000041"
+          ],
+          "status": "open",
+          "ruling": null,
+          "ruled_from": [],
+          "order": 3,
+          "options_hash": "7d95fc87d532420611fe415c1def27a3447617bb68235f46e3af130aea361c48"
+        }
       }
     ]
   },
diff --git a/contracts/cultnet/governance/fork-card.md b/contracts/cultnet/governance/fork-card.md
index 05c57827..dc30771b 100644
--- a/contracts/cultnet/governance/fork-card.md
+++ b/contracts/cultnet/governance/fork-card.md
@@ -31,7 +31,7 @@ All documents are CultNet map-mode: every key written, nil where absent, closed
 - `fork_id`: the mind's `question` key, `<campaign>:question:<label>`.
 - **Hashed (the shown members):** `title`, `context`, `options` (each `{id, text}`, in shown order), `recommendation` (an option id, **never nil**: the stored `question` requires `recommended`), `depends` (strings, each one of the stored question's `depends` lines verbatim, at most 8, each at most 1000 UTF-8 bytes (the stored `Line`), in shown order, empty when none; the stored kind holds prose lines, so a line may read like a reference such as `campaign:kind:label` but is hashed as the text it is).
 - **Not hashed:** `fork_id` (bound beside the hash), `leans` (an option id or nil), `flag`, `raised_in`, `deciders`, `status` (`open` or `closed`), `ruling` (the ruling id when a ruling closed the fork; nil when the card is open, and nil on a closed card whose question was withdrawn or otherwise resolved with no ruling), `ruled_from` (answer ids a ruling has been admitted from; non-empty only on a closed card), `order`, and `options_hash` itself.
-- **`deciders` is read-only data.** The list is set outside the Mind, through Bifrost's admin path, and **Bifrost sends it per call**: Huginn keeps no copy (M5). The card projection copies the list the call carried. A question's own `audience` may only narrow it. A Mind never writes it, so a Mind cannot add itself and answer its own fork.
+- **`deciders` is read-only data.** The list is set outside the Mind, through Bifrost's admin path, and **Bifrost sends it per call**: Huginn keeps no copy (M5). The card projection copies the list the call carried. **The list holds one to 64 ids** (Huginn's bound), on the card and in the per-call list alike (vectors `deciders_at_the_cap_of_64`, `deciders_65`); the per-call list has no schema here, so the bound is stated for the cut that builds it. A question's own `audience` may only narrow it. A Mind never writes it, so a Mind cannot add itself and answer its own fork.
 - Rules a schema cannot say, each with a negative vector: a `depends` line is at most 1000 UTF-8 bytes (the schema bounds 8 lines and 1000 characters; bytes need the rule); option ids are unique; `recommendation` and `leans` name an option; deciders are unique; an open card names no `ruling` and its `ruled_from` is empty (a ruling that answers a fork closes it); `ruled_from` is non-empty only when `ruling` is set; a closed card may name no ruling (the question was withdrawn, superseded or deferred: step 6 reads `status`, not the ruling); `options_hash` equals the hash of the shown members.
 
 ### Options hash (canonical bytes)
diff --git a/contracts/cultnet/governance/fork-card.schema.json b/contracts/cultnet/governance/fork-card.schema.json
index dba8ec80..62acc30a 100644
--- a/contracts/cultnet/governance/fork-card.schema.json
+++ b/contracts/cultnet/governance/fork-card.schema.json
@@ -149,7 +149,8 @@
           "items": {
             "type": "string",
             "minLength": 1
-          }
+          },
+          "maxItems": 64
         },
         "status": {
           "enum": [
diff --git a/scripts/gen-governance-vectors.py b/scripts/gen-governance-vectors.py
index 4b97cc0c..de42df47 100644
--- a/scripts/gen-governance-vectors.py
+++ b/scripts/gen-governance-vectors.py
@@ -474,6 +474,7 @@ MINDCASES = [
 SAME_RESPONSE = [["M2_read_unknown_mind_known_fork", "M2_read_known_mind_unknown_fork"], ["M2_answer_unknown_mind_known_fork", "M2_answer_known_mind_unknown_fork"],
                  ["M2_list_unknown_mind", "M2_read_known_mind_unknown_fork"], ["M3_answer_on_nibu_with_a_fork_gamecult_chat_holds", "M2_answer_known_mind_unknown_fork"]]
 def bad(name, why, m, **kw): return dict({"name": name, "why": why, "message": m}, **kw)
+DECIDERS_64 = [f"{i:08x}-0000-4000-8000-{i:012x}" for i in range(1, 65)]   # the card's `deciders` holds at most 64 (Huginn's bound)
 # body_sha256: Huginn's private "same body" digest (fork-card.md, "The mind's record"); no wire document carries it. Input per
 # /opt/commons/handoff/desk-body-digest-order-20261110.md (Eureka): SHA-256 of compact serde_json UTF-8, keys in this order, null for missing,
 # `retracts` the full stored key, request_id out. `illegal_retraction` and `retracted` are written only when the input has them (non-null).
@@ -507,7 +508,8 @@ fork = {
                      {"name": "leans_flag_closed_two_deciders", "message": card(leans="yes", flag="provisional: Self expects this to move", deciders=[OP, HM], depends=[], raised_in=None, status="closed", ruling="x:resolution:y", ruled_from=["n1"], order=0),
                       "messagePackHex": hx(card(leans="yes", flag="provisional: Self expects this to move", deciders=[OP, HM], depends=[], raised_in=None, status="closed", ruling="x:resolution:y", ruled_from=["n1"], order=0))},
                      {"name": "depends_at_both_caps", "message": card(depends=["a"] * 7 + ["\u00e9" * 500]), "messagePackHex": hx(card(depends=["a"] * 7 + ["\u00e9" * 500]))},
-                     {"name": "closed_without_a_ruling_the_question_was_withdrawn", "message": card(status="closed"), "messagePackHex": hx(card(status="closed"))}],
+                     {"name": "closed_without_a_ruling_the_question_was_withdrawn", "message": card(status="closed"), "messagePackHex": hx(card(status="closed"))},
+                     {"name": "deciders_at_the_cap_of_64", "message": card(deciders=DECIDERS_64), "messagePackHex": hx(card(deciders=DECIDERS_64))}],
            "invalid": [bad(n, w, m) for n, w, m in [
                ("depends_nine_lines", "depends holds at most 8 lines (the stored question's limit)", card(depends=["a"] * 9)),
                ("depends_line_1001_code_points", "a depends line is at most 1000 characters", card(depends=["a" * 1001])),
@@ -528,6 +530,7 @@ fork = {
                ("open_card_names_a_ruling", "rule: only a closed card names a ruling (not expressible in the schema)", card(ruling="cultlib-gaps:resolution:question.slot-mark-consent.n1")),
                ("ruled_from_without_a_ruling", "rule: ruled_from lists answers a ruling was admitted from, so it needs the ruling (not expressible in the schema)", card(status="closed", ruled_from=["n1"])),
                ("options_hash_of_another_card", "rule: options_hash equals the hash of the shown members (not expressible in the schema)", dict(card(), options_hash=STALE_H)),
+               ("deciders_65", "deciders holds at most 64 (Huginn's bound)", card(deciders=DECIDERS_64 + ["00000041-0000-4000-8000-000000000041"])),
            ]]},
   "request": {"valid": [{"name": n, "message": m, "messagePackHex": hx(m)} for n, m in
                        [("choice_and_note", x1), ("choice_alone", pick), ("note_alone_clear_pick", words), ("retraction", retraction("n1")),