--- a/.local/text-navigation-probe-20260911/source_symbols.rs
+++ b/.local/text-navigation-probe-20260911/source_symbols.rs
@@ -7,9 +7,9 @@
 //! Its matches are authored lexical uses, not typed semantic dependency edges.
 
 use oa_core::language::{Span, TokenClass, TokenSpan};
 use oa_core::Id;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::ops::Range;
 
 /// Fresh editor/workspace session identity plus a revision changed for EVERY
 /// indexed input change, including membership, outline and validation evidence.
@@ -357,16 +357,19 @@
             || files.iter().any(|file| file.membership == Membership::Unverified))
     {
         return Err(input_error(0, None, InputProblem::InconsistentCompleteScope));
     }
+    // Scratch storage is allocated only after aggregate file/path admission.
+    // Each admitted path is folded once, retaining core's Unicode policy.
+    let mut folded_paths = BTreeSet::new();
     for (file_index, file) in files.iter().copied().enumerate() {
         if file.syntax != SyntaxCoverage::FullFile {
             return Err(input_error(file_index, None, InputProblem::IncompleteSyntax));
         }
         if oa_core::source_project::resolve_include("", file.path).as_deref() != Ok(file.path) {
             return Err(input_error(file_index, None, InputProblem::NonCanonicalPath));
         }
-        if files[..file_index].iter().any(|other| other.path.eq_ignore_ascii_case(file.path)) {
+        if !folded_paths.insert(file.path.to_lowercase()) {
             return Err(input_error(file_index, None, InputProblem::DuplicateOrCaseCollidingPath));
         }
         let mut end = 0;
         for (token_index, token) in file.tokens.iter().enumerate() {
@@ -417,8 +420,9 @@
                 }
                 let literal = &file.text[identity.literal_span.start..identity.literal_span.end];
                 let decoded = serde_json::from_str::<String>(literal)
                     .ok()
+                    .filter(|value| oa_core::language::has_uuid_header_shape(value))
                     .and_then(|value| Id::parse_str(&value).ok());
                 if decoded != Some(identity.id) {
                     return Err(problem(InputProblem::IdentityLiteral));
                 }
@@ -1005,8 +1009,84 @@
         }
     }
 
     #[test]
+    fn unicode_path_collisions_match_core_lowercase_policy() {
+        for (first_path, second_path) in [("Ä.arcadia", "ä.arcadia"), ("ΟΣ/model.arcadia", "ος/model.arcadia")] {
+            let first = Fixture::new(first_path, "source @a;".into(), &[]);
+            let second = Fixture::new(second_path, "source @b;".into(), &[]);
+            assert_eq!(first_path.to_lowercase(), second_path.to_lowercase());
+            assert!(!first_path.eq_ignore_ascii_case(second_path));
+            assert!(matches!(Index::build(snapshot(1), &[first.included(), second.included()], Scope::CompleteProject, limits()), Err(BuildError::Input { problem: InputProblem::DuplicateOrCaseCollidingPath, .. })));
+        }
+    }
+
+    #[test]
+    fn noncanonical_header_identity_cannot_enter_through_query_metadata() {
+        for raw in [
+            "00000000000000000000000000000001",
+            "{00000000-0000-0000-0000-000000000001}",
+            "urn:uuid:00000000-0000-0000-0000-000000000001",
+        ] {
+            let literal = format!("\"{raw}\"");
+            let source = format!("oa_actor a \"A\" id {literal} {{}}\nsource @a;");
+            let mut fixture = Fixture::new("project.arcadia", source.clone(), &[("oa_actor", "a", None)]);
+            let start = source.find(&literal).unwrap();
+            // This fixture has one explicit empty body. A brace inside the
+            // quoted UUID must not become the test's declaration end.
+            let body_start = source.find("{}\n").unwrap();
+            fixture.declarations[0].span.end = body_start + 2;
+            assert!(start + literal.len() <= body_start);
+            // An adapter passes None from the corrected outline; lexical
+            // definition/reference navigation survives without an ID anchor.
+            {
+                let admitted = index(&[fixture.included()]);
+                let d = definition(&admitted, "a");
+                assert_eq!(admitted.identity(d), Ok(Identity::Missing));
+                assert_eq!(admitted.references_to(d, Domain::Included).unwrap().count(), 1);
+                assert_eq!(admitted.source(0).unwrap().text, source);
+            }
+            // A forged/stale caller cannot put the UUID crate's permissive
+            // interpretation back into an authored anchor via the raw API.
+            fixture.declarations[0].identity = Some(AuthoredIdentity {
+                id: A,
+                literal_span: Span { start, end: start + literal.len() },
+            });
+            assert!(matches!(Index::build(snapshot(1), &[fixture.included()], Scope::CompleteProject, limits()), Err(BuildError::Input { problem: InputProblem::IdentityLiteral, .. })));
+        }
+    }
+
+    #[test]
+    fn query_header_admission_preserves_uppercase_and_json_escape_bytes() {
+        let expected = Id::from_u128(0xabcdef);
+        let uppercase = expected.to_string().to_uppercase();
+        for raw in [uppercase.clone(), format!("\\u0030{}", &uppercase[1..])] {
+            let literal = format!("\"{raw}\"");
+            let source = format!("oa_actor a \"A\" id {literal} {{}}\nsource @a;");
+            let mut fixture = Fixture::new("project.arcadia", source.clone(), &[("oa_actor", "a", None)]);
+            let start = source.find(&literal).unwrap();
+            fixture.declarations[0].identity = Some(AuthoredIdentity {
+                id: expected,
+                literal_span: Span { start, end: start + literal.len() },
+            });
+            let admitted = index(&[fixture.included()]);
+            assert_eq!(anchor(&admitted, definition(&admitted, "a")).id(), expected);
+            assert_eq!(admitted.source(0).unwrap().text.as_bytes(), source.as_bytes());
+        }
+    }
+
+    #[test]
+    fn admitted_unicode_path_budget_keeps_original_policy_after_single_fold() {
+        let fixture = Fixture::new("İ.arcadia", String::new(), &[]);
+        assert!(fixture.path.to_lowercase().len() > fixture.path.len());
+        let exact = Limits { files: 1, source_bytes: 0, path_bytes: fixture.path.len(), tokens: 0, records: 0 };
+        let admitted = Index::build(snapshot(1), &[fixture.included()], Scope::CompleteProject, exact).unwrap();
+        assert_eq!(admitted.source(0).unwrap().path, "İ.arcadia");
+        // PathBytes continues to count authored input. One lowercase key's
+        // Unicode expansion is bounded scratch, not a new path rejection rule.
+    }
+
+    #[test]
     fn every_budget_admits_boundary_and_returns_no_index_one_below() {
         let fixture = Fixture::new("project.arcadia", "oa_actor a \"Text\" {}\nsource @a; target @a;".into(), &[("oa_actor", "a", None)]);
         let exact = Limits { files: 1, source_bytes: fixture.text.len(), path_bytes: fixture.path.len(), tokens: fixture.tokens.len(), records: 3 };
         assert!(Index::build(snapshot(1), &[fixture.included()], Scope::CompleteProject, exact).is_ok());