diff --git a/crates/aura-campaign/src/lib.rs b/crates/aura-campaign/src/lib.rs
index 35ce75c..3c43a68 100644
--- a/crates/aura-campaign/src/lib.rs
+++ b/crates/aura-campaign/src/lib.rs
@@ -475,6 +475,7 @@ mod tests {
             data: DataSection {
                 instruments: vec!["EURUSD".to_string()],
                 windows: vec![Window { from_ms: 0, to_ms: 10_000 }],
+                bindings: BTreeMap::new(),
             },
             risk: vec![],
             strategies: vec![StrategyEntry {
@@ -901,6 +902,7 @@ mod wf_tests {
             data: DataSection {
                 instruments: vec!["SYNTH".to_string()],
                 windows: vec![Window { from_ms: window.0, to_ms: window.1 }],
+                bindings: BTreeMap::new(),
             },
             risk: vec![],
             strategies: vec![StrategyEntry {
diff --git a/crates/aura-campaign/tests/execute.rs b/crates/aura-campaign/tests/execute.rs
index da3800d..c28ae7c 100644
--- a/crates/aura-campaign/tests/execute.rs
+++ b/crates/aura-campaign/tests/execute.rs
@@ -149,6 +149,7 @@ fn campaign(instruments: &[&str]) -> CampaignDoc {
         data: DataSection {
             instruments: instruments.iter().map(|s| s.to_string()).collect(),
             windows: vec![Window { from_ms: 1_000, to_ms: 9_000 }],
+            bindings: BTreeMap::new(),
         },
         risk: vec![],
         strategies: vec![StrategyEntry {
diff --git a/crates/aura-cli/src/binding.rs b/crates/aura-cli/src/binding.rs
index f75adf8..ec24a28 100644
--- a/crates/aura-cli/src/binding.rs
+++ b/crates/aura-cli/src/binding.rs
@@ -255,6 +255,19 @@ mod tests {
         assert_eq!(column_for_role("sentiment"), None);
     }
 
+    /// The doc-tier value vocabulary (aura-research) and this module's
+    /// role->column map agree exactly — the #160-style two-surface pin, so
+    /// the campaign-validate tier and the bind tier cannot drift.
+    #[test]
+    fn research_vocabulary_agrees_with_column_for_role() {
+        let vocab = aura_research::binding_column_vocabulary();
+        assert_eq!(vocab.len(), 7, "six columns + the price alias");
+        for token in vocab {
+            assert!(column_for_role(token).is_some(), "doc-tier token {token} must resolve");
+        }
+        assert!(column_for_role("hl2").is_none(), "non-vocabulary tokens must not resolve");
+    }
+
     /// Volume is the one i64 column (mirrors `aura_ingest::decode`).
     #[test]
     fn column_kind_is_i64_for_volume_and_f64_otherwise() {
diff --git a/crates/aura-cli/src/campaign_run.rs b/crates/aura-cli/src/campaign_run.rs
index 4e0e3cf..0f26ca2 100644
--- a/crates/aura-cli/src/campaign_run.rs
+++ b/crates/aura-cli/src/campaign_run.rs
@@ -228,6 +228,10 @@ pub(crate) fn bind_axes(
 struct CliMemberRunner<'a> {
     env: &'a Env,
     server: Arc<data_server::DataServer>,
+    /// The campaign's `data.bindings` overrides (role -> column), threaded
+    /// into per-member binding resolution (#231: rebind per campaign without
+    /// touching the blueprint's content id).
+    bindings: BTreeMap<String, String>,
 }
 
 impl MemberRunner for CliMemberRunner<'_> {
@@ -242,13 +246,13 @@ impl MemberRunner for CliMemberRunner<'_> {
         let space = crate::blueprint_axis_probe(&cell.blueprint_json, self.env).param_space();
         let point = bind_axes(&space, &cell.strategy_id, params)?;
 
-        // The member's blueprint + its resolved input binding (name defaults;
-        // the campaign's data.bindings overrides thread through in the
-        // DataSection task). A refusal is a member fault, never a process exit.
+        // The member's blueprint + its resolved input binding (campaign
+        // data.bindings overrides win over name defaults). A refusal is a
+        // member fault, never a process exit.
         let signal = blueprint_from_json(&cell.blueprint_json, &|t| self.env.resolve(t))
             .expect("stored blueprint passed the referential gate; reload is infallible");
         let binding =
-            crate::binding::resolve_binding(&cell.strategy_id, signal.input_roles(), &BTreeMap::new())
+            crate::binding::resolve_binding(&cell.strategy_id, signal.input_roles(), &self.bindings)
                 .map_err(MemberFault::Bind)?;
 
         // Real windowed data — geometry BEFORE bar data (the shipped pre-data
@@ -477,6 +481,7 @@ pub(crate) fn run_campaign_returning(
     let runner = CliMemberRunner {
         env,
         server: Arc::new(data_server::DataServer::new(env.data_path())),
+        bindings: campaign.data.bindings.clone(),
     };
     let outcome = aura_campaign::execute(
         campaign_id,
@@ -828,10 +833,14 @@ pub(crate) fn persist_campaign_traces(
             };
             let signal = blueprint_from_json(blueprint_json, &|t| env.resolve(t))
                 .expect("stored blueprint passed the referential gate; reload is infallible");
-            // Same name-default binding the member ran under (campaign
-            // overrides thread through in the DataSection task).
-            let binding =
-                crate::binding::resolve_binding(&cell_rec.strategy, signal.input_roles(), &BTreeMap::new())?;
+            // Campaign data.bindings overrides win over name defaults — the
+            // SAME resolution the member ran under, so the C1 drift alarm
+            // compares like with like.
+            let binding = crate::binding::resolve_binding(
+                &cell_rec.strategy,
+                signal.input_roles(),
+                &campaign.data.bindings,
+            )?;
             let sources = open_columns_window(
                 server,
                 &cell_rec.instrument,
diff --git a/crates/aura-cli/src/research_docs.rs b/crates/aura-cli/src/research_docs.rs
index 14637cc..07a53a0 100644
--- a/crates/aura-cli/src/research_docs.rs
+++ b/crates/aura-cli/src/research_docs.rs
@@ -6,10 +6,10 @@
 use std::path::PathBuf;
 
 use aura_research::{
-    campaign_to_json, campaign_vocabulary, describe_block, open_slots_campaign,
-    open_slots_process, parse_campaign, parse_process, process_to_json, process_vocabulary,
-    slot_kind_label, tap_vocabulary, validate_campaign, validate_process, CampaignDoc, DocError,
-    DocFault, DocKind, ProcessDoc, StageBlock,
+    binding_column_vocabulary_display, campaign_to_json, campaign_vocabulary, describe_block,
+    open_slots_campaign, open_slots_process, parse_campaign, parse_process, process_to_json,
+    process_vocabulary, slot_kind_label, tap_vocabulary, validate_campaign, validate_process,
+    CampaignDoc, DocError, DocFault, DocKind, ProcessDoc, StageBlock,
 };
 use aura_registry::RefFault;
 
@@ -154,6 +154,10 @@ pub(crate) fn doc_fault_prose(f: &DocFault) -> String {
             "presentation.persist_taps[{index}]: unknown tap \"{tap}\" (taps: {})",
             tap_vocabulary().join(" | ")
         ),
+        DocFault::UnknownBindingColumn { role, column } => format!(
+            "data.bindings.{role}: \"{column}\" names no archive column (columns: {})",
+            binding_column_vocabulary_display()
+        ),
         DocFault::ProcessRefMustBeContentId => {
             "process.ref: a process is referenced by content id in this version".into()
         }
@@ -331,6 +335,10 @@ pub(crate) fn ref_fault_prose(f: &RefFault) -> String {
         RefFault::ParamNotCovered { strategy, param } => {
             format!("strategy {strategy}: open param \"{param}\" is bound by no campaign axis")
         }
+        RefFault::BindingRoleUnknown { role, roles } => format!(
+            "data.bindings: key \"{role}\" names no input role of any campaign strategy (roles: {})",
+            roles.join(", ")
+        ),
     }
 }
 
@@ -537,6 +545,22 @@ fn introspect_campaign(cmd: &DocIntrospectCmd) -> Result<(), String> {
 mod tests {
     use super::*;
 
+    /// Exact prose pin for the binding-key referential refusal (#231): the
+    /// message is path-addressed, names the offending key, and lists the
+    /// strategies' actual roles.
+    #[test]
+    fn binding_role_unknown_prose_names_key_and_roles() {
+        let msg = ref_fault_prose(&RefFault::BindingRoleUnknown {
+            role: "sentiment".into(),
+            roles: vec!["price".into(), "high".into()],
+        });
+        assert_eq!(
+            msg,
+            "data.bindings: key \"sentiment\" names no input role of any campaign \
+             strategy (roles: price, high)"
+        );
+    }
+
     #[test]
     fn ref_fault_prose_is_debug_free() {
         let cases = [
diff --git a/crates/aura-cli/src/verb_sugar.rs b/crates/aura-cli/src/verb_sugar.rs
index e0b8ae5..a5a5ef5 100644
--- a/crates/aura-cli/src/verb_sugar.rs
+++ b/crates/aura-cli/src/verb_sugar.rs
@@ -148,6 +148,9 @@ pub(crate) fn translate_sweep(inv: &SugarInvocation) -> Result<GeneratedSweep, S
         data: DataSection {
             instruments: inv.symbols.clone(),
             windows: vec![Window { from_ms: inv.from_ms, to_ms: inv.to_ms }],
+            // The verb sugar passes no bindings: name defaults rule (#231);
+            // authored campaign documents may set them.
+            bindings: BTreeMap::new(),
         },
         strategies: vec![StrategyEntry {
             r#ref: DocRef::ContentId(content_id_of(inv.blueprint_canonical)),
@@ -226,6 +229,9 @@ pub(crate) fn translate_generalize(
         data: DataSection {
             instruments: inv.symbols.clone(),
             windows: vec![Window { from_ms: inv.from_ms, to_ms: inv.to_ms }],
+            // The verb sugar passes no bindings: name defaults rule (#231);
+            // authored campaign documents may set them.
+            bindings: BTreeMap::new(),
         },
         strategies: vec![StrategyEntry {
             r#ref: DocRef::ContentId(content_id_of(inv.blueprint_canonical)),
@@ -425,6 +431,9 @@ pub(crate) fn translate_walkforward(
         data: DataSection {
             instruments: inv.symbols.clone(),
             windows: vec![Window { from_ms: inv.from_ms, to_ms: inv.to_ms }],
+            // The verb sugar passes no bindings: name defaults rule (#231);
+            // authored campaign documents may set them.
+            bindings: BTreeMap::new(),
         },
         strategies: vec![StrategyEntry {
             r#ref: DocRef::ContentId(content_id_of(inv.blueprint_canonical)),
@@ -577,6 +586,9 @@ pub(crate) fn translate_mc(
         data: DataSection {
             instruments: inv.symbols.clone(),
             windows: vec![Window { from_ms: inv.from_ms, to_ms: inv.to_ms }],
+            // The verb sugar passes no bindings: name defaults rule (#231);
+            // authored campaign documents may set them.
+            bindings: BTreeMap::new(),
         },
         strategies: vec![StrategyEntry {
             r#ref: DocRef::ContentId(content_id_of(inv.blueprint_canonical)),
diff --git a/crates/aura-cli/tests/research_docs.rs b/crates/aura-cli/tests/research_docs.rs
index 4093dfc..23137fd 100644
--- a/crates/aura-cli/tests/research_docs.rs
+++ b/crates/aura-cli/tests/research_docs.rs
@@ -746,6 +746,29 @@ fn campaign_introspect_unwired_reports_placeholder_refs() {
     );
 }
 
+/// The intrinsic tier value-checks `data.bindings` (no project, no store,
+/// #231): a value outside the closed column vocabulary refuses
+/// path-addressed, naming the vocabulary. NOT gated.
+#[test]
+fn campaign_validate_refuses_an_unknown_binding_column() {
+    let dir = temp_cwd("campaign-validate-bad-binding");
+    let doc = r#"{ "format_version": 1, "kind": "campaign", "name": "bad-binding",
+        "data": { "bindings": { "price": "hl2" },
+                  "instruments": ["GER40"], "windows": [ { "from_ms": 1, "to_ms": 2 } ] },
+        "strategies": [ { "ref": { "content_id": "9f3a" },
+                          "axes": { "slow": { "kind": "I64", "values": [10] } } } ],
+        "process": { "ref": { "content_id": "9f3a" } },
+        "seed": 1,
+        "presentation": { "persist_taps": [], "emit": [] } }"#;
+    write_doc(&dir, "bad.campaign.json", doc);
+    let (out, code) = run_code_in(&dir, &["campaign", "validate", "bad.campaign.json"]);
+    assert_eq!(code, Some(1), "stdout/stderr: {out}");
+    assert!(
+        out.contains(r#"data.bindings.price: "hl2" names no archive column"#),
+        "the refusal is path-addressed and names the vocabulary: {out}"
+    );
+}
+
 /// The campaign twin of `process_introspect_vocabulary_block_and_content_id`'s
 /// `--content-id` branch: pins that `campaign introspect --content-id` wires
 /// `parse_valid_campaign` + `campaign_to_json` + `content_id_of` end to end
@@ -1991,6 +2014,66 @@ fn campaign_run_real_e2e_sweep_gate_walkforward() {
     );
 }
 
+/// The campaign `data.bindings` override end to end (#231, 6b): the same
+/// seeded strategy, window, and seed run twice — bare (price<-close default)
+/// and with `price` rebound to the open column. Both exit 0; the realized
+/// member metrics differ (the open series is not the close series); the
+/// strategy blueprint is untouched (both docs reference the same content id).
+/// Gated on the local GER40 archive; skips cleanly when absent.
+#[test]
+fn campaign_run_real_e2e_bindings_override_rebinds_price_to_open() {
+    let _fixture = project_lock();
+    let dir = built_project();
+    let runs_dir = dir.join("runs");
+    std::fs::remove_dir_all(&runs_dir).ok();
+    let _cleanup = ScratchGuard(vec![
+        ScratchPath::Dir(runs_dir.clone()),
+        ScratchPath::File(dir.join("sweep.process.json")),
+        ScratchPath::File(dir.join("close.campaign.json")),
+        ScratchPath::File(dir.join("open.campaign.json")),
+    ]);
+    let bp_id = seed_blueprint(dir, "binding-override-seed");
+    let proc_id = register_process_doc(dir, "sweep.process.json", SWEEP_ONLY_PROCESS_DOC);
+    let base = campaign_doc_json(
+        &bp_id,
+        &proc_id,
+        (1725148800000, 1727740799999),
+        "",
+        "\"family_table\"",
+    );
+    let rebound = base.replace(
+        r#""data": { "instruments": ["GER40"],"#,
+        r#""data": { "bindings": { "price": "open" }, "instruments": ["GER40"],"#,
+    );
+    assert_ne!(rebound, base, "the override splice must hit the data section");
+    write_doc(dir, "close.campaign.json", &base);
+    write_doc(dir, "open.campaign.json", &rebound);
+
+    let (out_close, code_close) = run_code_in(dir, &["campaign", "run", "close.campaign.json"]);
+    if code_close == Some(1)
+        && (out_close.contains("no recorded geometry") || out_close.contains("no data for instrument"))
+    {
+        eprintln!("skip: no local GER40 data for the binding-override e2e");
+        return;
+    }
+    assert_eq!(code_close, Some(0), "stdout/stderr: {out_close}");
+    let (out_open, code_open) = run_code_in(dir, &["campaign", "run", "open.campaign.json"]);
+    assert_eq!(code_open, Some(0), "stdout/stderr: {out_open}");
+
+    let first_member = |out: &str| -> serde_json::Value {
+        out.lines()
+            .find(|l| l.starts_with("{\"family_id\":"))
+            .map(|l| serde_json::from_str(l).expect("member line parses"))
+            .expect("a family_table member line")
+    };
+    let close_metrics = first_member(&out_close)["report"]["metrics"].clone();
+    let open_metrics = first_member(&out_open)["report"]["metrics"].clone();
+    assert_ne!(
+        close_metrics, open_metrics,
+        "rebinding price<-open must change the realized member metrics"
+    );
+}
+
 /// Property (#210 T3, Task 4 Step 9 — the regime->stop map): a campaign
 /// document's non-default risk regime (`risk: [{ "vol": { length, k } }]`)
 /// reaches the real `CliMemberRunner::run_member` path and IS the stop actually
diff --git a/crates/aura-registry/src/lib.rs b/crates/aura-registry/src/lib.rs
index c42c4ab..20afd81 100644
--- a/crates/aura-registry/src/lib.rs
+++ b/crates/aura-registry/src/lib.rs
@@ -218,6 +218,10 @@ pub enum RefFault {
     /// time so "valid" means "runnable". Carries the RAW `param_space()`
     /// path (never the wrapped bind-time path).
     ParamNotCovered { strategy: String, param: String },
+    /// A campaign `data.bindings` key that names no input role of any
+    /// strategy in the campaign — the override would silently bind nothing
+    /// (#231). Carries the strategies' actual role names for the prose.
+    BindingRoleUnknown { role: String, roles: Vec<String> },
 }
 
 impl Registry {
@@ -231,6 +235,7 @@ impl Registry {
         resolve: &dyn Fn(&str) -> Option<PrimitiveBuilder>,
     ) -> Result<Vec<RefFault>, RegistryError> {
         let mut faults = Vec::new();
+        let mut known_roles: std::collections::BTreeSet<String> = std::collections::BTreeSet::new();
 
         if let DocRef::ContentId(id) = &doc.process.r#ref
             && self.get_process(id)?.is_none()
@@ -266,6 +271,9 @@ impl Registry {
                     continue;
                 }
             };
+            for role in composite.input_roles() {
+                known_roles.insert(role.name.clone());
+            }
             let space = composite.param_space();
             for (axis, ax) in &entry.axes {
                 match space.iter().find(|p| &p.name == axis) {
@@ -294,6 +302,18 @@ impl Registry {
                 }
             }
         }
+        // Binding KEYS (the 6b overrides): each must name an input role of at
+        // least one campaign strategy — checked in this tier (not the
+        // intrinsic one) because only the resolver sees the loaded blueprints'
+        // roles. Binding VALUES are the intrinsic tier's concern.
+        for role in doc.data.bindings.keys() {
+            if !known_roles.contains(role) {
+                faults.push(RefFault::BindingRoleUnknown {
+                    role: role.clone(),
+                    roles: known_roles.iter().cloned().collect(),
+                });
+            }
+        }
         Ok(faults)
     }
 
@@ -1693,6 +1713,72 @@ mod tests {
         );
     }
 
+    /// Property (#231): the referential tier checks campaign `data.bindings`
+    /// KEYS against the resolved strategies' input roles (the 6b override
+    /// seam) — a key naming no role of any strategy faults with the actual
+    /// roles listed; a key naming a real role passes. The sibling of the
+    /// unknown-axis check above; values are the intrinsic tier's concern.
+    #[test]
+    fn referential_tier_checks_binding_keys_against_strategy_roles() {
+        use aura_engine::{blueprint_to_json, Composite, Role, Target};
+
+        let reg = Registry::open(temp_family_dir("binding_keys"));
+        let resolve = |t: &str| aura_std::std_vocabulary(t);
+
+        // The referential fixture composite (see
+        // referential_tier_resolves_refs_and_checks_axes), plus ONE input
+        // role so a binding key has something to name.
+        let composite = Composite::new(
+            "fixture",
+            vec![aura_std::Bias::builder().named("b").into()],
+            vec![],
+            vec![Role {
+                name: "price".to_string(),
+                targets: vec![Target { node: 0, slot: 0 }],
+                source: Some(aura_core::ScalarKind::F64),
+            }],
+            vec![],
+        );
+        let space = composite.param_space();
+        let axis = space.first().expect("fixture has an open param").name.clone();
+        let blueprint_json = blueprint_to_json(&composite).expect("serializes");
+        let bp_id = aura_research::content_id_of(&blueprint_json);
+        reg.put_blueprint(&bp_id, &blueprint_json).expect("seed blueprint");
+        let process = r#"{"format_version":1,"kind":"process","name":"p","pipeline":[{"block":"std::generalize","metric":"sqn"}]}"#;
+        let proc_id = reg.put_process(process).expect("seed process");
+        let campaign_text = format!(
+            concat!(
+                r#"{{"format_version":1,"kind":"campaign","name":"c","#,
+                r#""data":{{"bindings":{{"price":"open"}},"instruments":["GER40"],"windows":[{{"from_ms":1,"to_ms":2}}]}},"#,
+                r#""strategies":[{{"ref":{{"content_id":"{bp}"}},"#,
+                r#""axes":{{"{axis}":{{"kind":"F64","values":[1.5]}}}}}}],"#,
+                r#""process":{{"ref":{{"content_id":"{proc}"}}}},"#,
+                r#""seed":1,"presentation":{{"persist_taps":[],"emit":["family_table"]}}}}"#
+            ),
+            bp = bp_id,
+            axis = axis,
+            proc = proc_id,
+        );
+        let doc = aura_research::parse_campaign(&campaign_text).expect("campaign parses");
+        assert_eq!(
+            reg.validate_campaign_refs(&doc, &resolve).expect("io ok"),
+            Vec::new(),
+            "a binding key naming a real strategy role is fault-free",
+        );
+
+        let mut bad = doc.clone();
+        bad.data.bindings.insert("nope".to_string(), "close".to_string());
+        let faults = reg.validate_campaign_refs(&bad, &resolve).expect("io ok");
+        assert!(
+            faults.iter().any(|f| matches!(
+                f,
+                RefFault::BindingRoleUnknown { role, roles }
+                    if role == "nope" && roles == &vec!["price".to_string()]
+            )),
+            "a key naming no strategy role must fault, listing the actual roles; got {faults:?}",
+        );
+    }
+
     #[test]
     fn check_r_metric_accepts_r_and_refuses_pip() {
         assert!(check_r_metric("expectancy_r").is_ok());
diff --git a/crates/aura-research/src/lib.rs b/crates/aura-research/src/lib.rs
index 62b4b63..57eaa4c 100644
--- a/crates/aura-research/src/lib.rs
+++ b/crates/aura-research/src/lib.rs
@@ -442,12 +442,19 @@ pub struct CampaignDoc {
     pub presentation: Presentation,
 }
 
-/// Structural data axes: which instruments over which windows.
+/// Structural data axes: which instruments over which windows, plus the
+/// optional per-campaign input-binding overrides (role name -> column name,
+/// #231 — the campaign rebind seam: re-aim a strategy's input roles without
+/// touching its blueprint's content identity). Additive on the
+/// `description`/`risk` precedent: absent-serializes, so binding-less
+/// documents keep their content ids.
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 #[serde(deny_unknown_fields)]
 pub struct DataSection {
     pub instruments: Vec<String>,
     pub windows: Vec<Window>,
+    #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
+    pub bindings: BTreeMap<String, String>,
 }
 
 /// One data window, inclusive epoch-ms bounds (the CLI --from/--to form).
@@ -665,6 +672,21 @@ pub fn tap_vocabulary() -> &'static [&'static str] {
     &["equity", "exposure", "r_equity", "net_r_equity"]
 }
 
+/// The closed archive-column vocabulary a campaign `data.bindings` VALUE may
+/// name — the six M1 columns plus `price`, the alias of close. Doc-tier
+/// mirror of the CLI binding module's role->column map (the `tap_vocabulary`
+/// precedent for doc-tier string tables); the CLI pins the two surfaces
+/// against each other in `binding::tests`.
+pub fn binding_column_vocabulary() -> &'static [&'static str] {
+    &["open", "high", "low", "close", "price", "spread", "volume"]
+}
+
+/// The vocabulary in the refusal-prose register — the alias annotated
+/// instead of listed as a flat column (mirrors the CLI binding module).
+pub fn binding_column_vocabulary_display() -> &'static str {
+    "open | high | low | close (alias: price) | spread | volume"
+}
+
 /// Intrinsic-validation findings. By-identifier and Display-free.
 #[derive(Clone, Debug, PartialEq)]
 pub enum DocFault {
@@ -685,6 +707,7 @@ pub enum DocFault {
     EmptyAxis { strategy: usize, axis: String },
     UnknownEmitKind(String),
     UnknownTap { index: usize, tap: String },
+    UnknownBindingColumn { role: String, column: String },
     ProcessRefMustBeContentId,
 }
 
@@ -769,6 +792,17 @@ pub fn validate_campaign(doc: &CampaignDoc) -> Vec<DocFault> {
             faults.push(DocFault::BadWindow { index: i });
         }
     }
+    // Binding VALUES parse against the closed column vocabulary here (the
+    // structural tier — no blueprint access); binding KEYS are checked against
+    // the strategies' input roles in the resolver tier (validate_campaign_refs).
+    for (role, column) in &doc.data.bindings {
+        if !binding_column_vocabulary().contains(&column.as_str()) {
+            faults.push(DocFault::UnknownBindingColumn {
+                role: role.clone(),
+                column: column.clone(),
+            });
+        }
+    }
     for (i, r) in doc.risk.iter().enumerate() {
         let RiskRegime::Vol { length, k } = r;
         // length < 1 catches 0 and negatives; `k <= 0.0 || k.is_nan()` catches
@@ -1580,6 +1614,52 @@ mod tests {
         assert_eq!(validate_campaign(&all), Vec::new());
     }
 
+    /// The campaign `data.bindings` block (#231): serde-ADDITIVE (a
+    /// binding-less document serializes with NO "bindings" key — every stored
+    /// campaign's content id is byte-stable — and legacy text parses to an
+    /// empty map), round-trips when present, and value-checks against the
+    /// closed column vocabulary at the intrinsic tier.
+    #[test]
+    fn bindings_are_serde_additive_and_value_checked() {
+        let legacy = format!(
+            concat!(
+                r#"{{"format_version":1,"kind":"campaign","name":"c","#,
+                r#""data":{{"instruments":["GER40"],"windows":[{{"from_ms":1,"to_ms":2}}]}},"#,
+                r#""strategies":[{{"ref":{{"content_id":"{id}"}},"axes":{{"len":{{"kind":"I64","values":[2]}}}}}}],"#,
+                r#""process":{{"ref":{{"content_id":"{id}"}}}},"#,
+                r#""seed":1,"presentation":{{"persist_taps":[],"emit":[]}}}}"#
+            ),
+            id = "a".repeat(64),
+        );
+        let doc = parse_campaign(&legacy).expect("legacy campaign parses");
+        assert!(doc.data.bindings.is_empty());
+        assert!(!campaign_to_json(&doc).contains("bindings"));
+        assert!(validate_campaign(&doc).is_empty());
+
+        let with = legacy.replace(
+            r#""data":{"instruments""#,
+            r#""data":{"bindings":{"price":"open"},"instruments""#,
+        );
+        assert_ne!(with, legacy, "the fixture splice must hit");
+        let doc = parse_campaign(&with).expect("bindings campaign parses");
+        assert_eq!(doc.data.bindings.get("price").map(String::as_str), Some("open"));
+        assert!(campaign_to_json(&doc).contains(r#""bindings":{"price":"open"}"#));
+        assert!(validate_campaign(&doc).is_empty());
+
+        let bad = legacy.replace(
+            r#""data":{"instruments""#,
+            r#""data":{"bindings":{"price":"hl2"},"instruments""#,
+        );
+        let doc = parse_campaign(&bad).expect("parses (values are validate-tier)");
+        assert_eq!(
+            validate_campaign(&doc),
+            vec![DocFault::UnknownBindingColumn {
+                role: "price".to_string(),
+                column: "hl2".to_string()
+            }]
+        );
+    }
+
     /// The `std::presentation` persist_taps slot advertises the closed tap
     /// vocabulary through the describe path (`describe_block` +
     /// `slot_kind_label`); the label is cross-pinned against `tap_vocabulary()`