diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7067f7a..7073ec8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+- reject broad universes (`string`, `number`, template literals) and
+  value/stringification collisions (`true | "true"`, `1 | "1"`) at the factory
+- type handler parameters by the matched member (`Member<T, K>`), so a
+  standalone `"true"` universe is typed `"true"` rather than `true`
+
 ## [0.6.0] - 2026-09-22
 
 - add `getTaggedUnionMatcher` / `getTaggedUnionMatcherW` for discriminated unions
diff --git a/backlog.tasks b/backlog.tasks
index e457520..83a08ae 100644
--- a/backlog.tasks
+++ b/backlog.tasks
@@ -37,12 +37,12 @@ Testing:
     ✔ Rewrite `src/util/__tests__/lsp-completion.ts` onto `createMessageConnection` and typed requests @done
     ✔ Update `development/testing.md § Autocomplete` for the new client @done
     ✔ Run `npm run verify` and check the task off @done
-☐ Test a literal union widened with `(string & {})` — `"red" | "green" | "yellow" | (string & {})` @medium
-    → autocomplete should still offer the literals; arbitrary strings stay assignable and fall through to the fallback
-☐ Type hole when using broad types like string as a universe @high
-    ☐ handlers cannot be exhaustive, yet it is possible to not have a fallback
-    ☐ one test even exploits this, I think for a negative test
-    ☐ does the same type hole exist for tagged-union matchers or primitive-union matchers only?
+✘ Test a literal union widened with `(string & {})` — `"red" | "green" | "yellow" | (string & {})` @medium @cancelled
+    → broad universes are rejected; the rejection is covered by the broad-universe gate tests
+✔ Type hole when using broad types like string as a universe @high @done
+    → decided: broad universes are rejected at the factory, so the exhaustive overload can always be proven
+    → value/stringification collisions (`true | "true"`, `1 | "1"`) are rejected too; handler params are typed by `Member<T, K>`
+    → see development/library.md § Supported universes
 
 Matcher:
 ✔ Clean up: adopt the 3-overload matcher (`src/prototype-ac2.ts`) and delete the prototypes @high @done