diff --git a/crates/doc/src/config_clone.rs b/crates/doc/src/config_clone.rs
index efb174c44d..c85eed89e4 100644
--- a/crates/doc/src/config_clone.rs
+++ b/crates/doc/src/config_clone.rs
@@ -1,7 +1,7 @@
 //! Configuration graph remapping for independent component copies.
 use super::{Column, ConfigTable};
 use crate::{DocError, Result};
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 
 #[derive(Clone, Debug, Default)]
 pub struct ConfigCloneMaps {
@@ -102,6 +102,9 @@ impl ConfigTable {
                 }
             }
         }
+        // The ids taken so far, looked up rather than scanned: copies of rules whose ids share
+        // their first 40 characters try one id after another.
+        let mut taken: BTreeSet<String> = next.rules.iter().map(|rule| rule.id.clone()).collect();
         for rule in &self.rules {
             if let Some(mut copied) = rule.clone_for_targets(maps) {
                 if next.rules.len() >= super::MAX_RULES {
@@ -110,8 +113,9 @@ impl ConfigTable {
                 let stem: String = rule.id.chars().take(40).collect();
                 copied.id = (1..=super::MAX_RULES + 1)
                     .map(|i| format!("{stem}_copy{i}"))
-                    .find(|id| !next.rules.iter().any(|rule| rule.id == *id))
+                    .find(|id| !taken.contains(id))
                     .ok_or_else(|| DocError::Invalid("no configuration rule ID available".into()))?;
+                taken.insert(copied.id.clone());
                 copied.name = format!("{} (copy)", rule.name.chars().take(120).collect::<String>());
                 next.rules.push(copied);
             }
diff --git a/crates/doc/src/config_rules.rs b/crates/doc/src/config_rules.rs
index 87dea95f3c..1aa1f78cc4 100644
--- a/crates/doc/src/config_rules.rs
+++ b/crates/doc/src/config_rules.rs
@@ -6,7 +6,9 @@ use serde::{Deserialize, Serialize};
 use serde_json::Value;
 use std::collections::{BTreeMap, BTreeSet};
 
-pub const MAX_RULES: usize = 128;
+/// Most configuration rules a design keeps. A rule drives one feature's suppression, so an
+/// assembly that switches a few hundred parts on and off, by two rules each, needs hundreds.
+pub const MAX_RULES: usize = 2048;
 const MAX_NODES: usize = 64;
 const MAX_DEPTH: usize = 8;
 
@@ -626,7 +628,16 @@ mod tests {
         .unwrap();
         assert!(validate_rules_json(&serde_json::json!({"configs":{"rules":[valid.clone()]}})).is_ok());
         assert!(validate_rules_json(&serde_json::json!({"configs":{"rules":null}})).is_err());
-        assert!(validate_rules_json(&serde_json::json!({"configs":{"rules":vec![valid.clone();129]}})).is_err());
+        // An assembly that switches a few hundred parts on and off, by two rules each, keeps them.
+        let many: Vec<Value> = (0..600)
+            .map(|i| {
+                let mut r = valid.clone();
+                r["id"] = serde_json::json!(format!("r{i}"));
+                r
+            })
+            .collect();
+        assert!(validate_rules_json(&serde_json::json!({"configs":{"rules":many}})).is_ok());
+        assert!(validate_rules_json(&serde_json::json!({"configs":{"rules":vec![valid.clone();MAX_RULES + 1]}})).is_err());
         let mut condition = serde_json::json!({"type":"always"});
         for _ in 0..8 {
             condition = serde_json::json!({"type":"not","condition":condition});
@@ -690,7 +701,7 @@ mod tests {
             Value::Null,
             serde_json::json!([deep]),
             serde_json::json!([wide]),
-            serde_json::json!(vec![valid; 129]),
+            serde_json::json!(vec![valid; MAX_RULES + 1]),
             serde_json::json!([invalid_context]),
         ] {
             let mut saved = serde_json::to_value(design()).unwrap();
diff --git a/docs/configurations.md b/docs/configurations.md
index 11e43c7110..12c46bfc9f 100644
--- a/docs/configurations.md
+++ b/docs/configurations.md
@@ -147,7 +147,7 @@ or restrictions leave the previous document intact and explain the failure. Dele
 before removing the last row. Parameter renames update rule targets and expressions; rule
 references prevent parameter deletion until removed.
 
-Tables support at most 128 rules; conditions allow eight levels and 64 nodes, and allowed
+Tables support at most 2048 rules; conditions allow eight levels and 64 nodes, and allowed
 value lists support up to 128 expressions. These bounds are checked before saved rules are
 decoded. Driven appearance/material rules and repeated fixed-point evaluation are outside
 the current rule scope.