btravstack · btravers · Jul 28, 2026 · Jul 28, 2026
diff --git a/.changeset/pre.json b/.changeset/pre.json
@@ -26,6 +26,8 @@
     "oxlint-catch-all-recommended",
     "oxlint-four-rules",
     "oxlint-no-catch-all-pattern",
+    "oxlint-p-tag-message",
+    "p-tag-pattern",
     "prisma-transaction-defect",
     "remove-tools-packages",
     "rename-err-combinators-cases",

diff --git a/packages/boxed/CHANGELOG.md b/packages/boxed/CHANGELOG.md
@@ -1,5 +1,12 @@
 # @unthrown/boxed
 
+## 5.0.0-beta.9
+
+### Patch Changes
+
+- Updated dependencies [e43d44e]
+  - unthrown@5.0.0-beta.9
+
 ## 5.0.0-beta.8
 
 ### Patch Changes

diff --git a/packages/boxed/package.json b/packages/boxed/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@unthrown/boxed",
-  "version": "5.0.0-beta.8",
+  "version": "5.0.0-beta.9",
   "description": "Boxed interop for unthrown",
   "keywords": [
     "boxed",

diff --git a/packages/core/CHANGELOG.md b/packages/core/CHANGELOG.md
@@ -1,5 +1,41 @@
 # unthrown
 
+## 5.0.0-beta.9
+
+### Major Changes
+
+- e43d44e: **`tag(t)` moves onto the pattern namespace as `P.tag(t)`; the standalone
+  `tag` export is removed.** `tag` is a pattern constructor, and every other one
+  already lives on `P` (`P._` / `P.any` / `P.instanceOf` / `P.when` / `P.union` /
+  `P.string` / `P.number`) — having exactly one of them sitting loose in the root
+  export was the odd one out. There is no alias: one concept, one name.
+
+  The type and the runtime behaviour are unchanged — it still produces the
+  `{ _tag: t }` object pattern, still narrows to the matching variant with its
+  payload, and still works in grouped patterns and inside `P.union`.
+
+  Migration is mechanical: drop `tag` from the import (keeping or adding `P`) and
+  prefix the call sites. (The `- import { tag } from "unthrown"` line below is the
+  v5-beta spelling; coming from 4.x the import was `@unthrown/pattern`, which is
+  gone — see the v5 upgrade guide.)
+
+  ```diff
+  - import { tag } from "unthrown";
+  + import { P } from "unthrown";
+
+    result.mapErrCases((matcher) =>
+      matcher
+  -     .with(tag("NotFound"), () => new ApiError({ status: 404 }))
+  -     .with(tag("Conflict"), tag("DriverError"), (e) => defect(e.cause)),
+  +     .with(P.tag("NotFound"), () => new ApiError({ status: 404 }))
+  +     .with(P.tag("Conflict"), P.tag("DriverError"), (e) => defect(e.cause)),
+    );
+  ```
+
+  `TaggedError` (and the `TaggedErrorConstructor` / `TaggedErrorInstance` types)
+  are untouched and still exported from the root — only the matcher pattern
+  moved.
+
 ## 5.0.0-beta.8
 
 ## 5.0.0-beta.7

diff --git a/packages/core/package.json b/packages/core/package.json
@@ -1,6 +1,6 @@
 {
   "name": "unthrown",
-  "version": "5.0.0-beta.8",
+  "version": "5.0.0-beta.9",
   "description": "Explicit errors as values, with a separate defect (panic) channel",
   "keywords": [
     "defect",

diff --git a/packages/effect/CHANGELOG.md b/packages/effect/CHANGELOG.md
@@ -1,5 +1,12 @@
 # @unthrown/effect
 
+## 5.0.0-beta.9
+
+### Patch Changes
+
+- Updated dependencies [e43d44e]
+  - unthrown@5.0.0-beta.9
+
 ## 5.0.0-beta.8
 
 ### Patch Changes

diff --git a/packages/effect/package.json b/packages/effect/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@unthrown/effect",
-  "version": "5.0.0-beta.8",
+  "version": "5.0.0-beta.9",
   "description": "Effect interop for unthrown",
   "keywords": [
     "effect",

diff --git a/packages/neverthrow/CHANGELOG.md b/packages/neverthrow/CHANGELOG.md
@@ -1,5 +1,12 @@
 # @unthrown/neverthrow
 
+## 5.0.0-beta.9
+
+### Patch Changes
+
+- Updated dependencies [e43d44e]
+  - unthrown@5.0.0-beta.9
+
 ## 5.0.0-beta.8
 
 ### Patch Changes

diff --git a/packages/neverthrow/package.json b/packages/neverthrow/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@unthrown/neverthrow",
-  "version": "5.0.0-beta.8",
+  "version": "5.0.0-beta.9",
   "description": "neverthrow interop for unthrown",
   "keywords": [
     "errors-as-values",

diff --git a/packages/oxlint/CHANGELOG.md b/packages/oxlint/CHANGELOG.md
@@ -1,5 +1,15 @@
 # @unthrown/oxlint
 
+## 5.0.0-beta.9
+
+### Patch Changes
+
+- e43d44e: Update `no-catch-all-pattern`'s diagnostic and documentation to spell the
+  recommended form as `.with(P.tag("A"), P.tag("B"), …, handler)`, following
+  core's move of the `tag` pattern constructor onto the `P` namespace. No rule
+  behaviour, name, or option changed — only the guidance text a developer reads
+  when the rule fires.
+
 ## 5.0.0-beta.8
 
 ### Minor Changes

diff --git a/packages/oxlint/package.json b/packages/oxlint/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@unthrown/oxlint",
-  "version": "5.0.0-beta.8",
+  "version": "5.0.0-beta.9",
   "description": "oxlint plugin enforcing unthrown's conventions",
   "keywords": [
     "errors-as-values",

diff --git a/packages/standard-schema/CHANGELOG.md b/packages/standard-schema/CHANGELOG.md
@@ -1,5 +1,12 @@
 # @unthrown/standard-schema
 
+## 5.0.0-beta.9
+
+### Patch Changes
+
+- Updated dependencies [e43d44e]
+  - unthrown@5.0.0-beta.9
+
 ## 5.0.0-beta.8
 
 ### Patch Changes

diff --git a/packages/standard-schema/package.json b/packages/standard-schema/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@unthrown/standard-schema",
-  "version": "5.0.0-beta.8",
+  "version": "5.0.0-beta.9",
   "description": "Standard Schema (Zod, Valibot, ArkType, …) interop for unthrown",
   "keywords": [
     "arktype",

diff --git a/packages/vitest/CHANGELOG.md b/packages/vitest/CHANGELOG.md
@@ -1,5 +1,7 @@
 # @unthrown/vitest
 
+## 5.0.0-beta.9
+
 ## 5.0.0-beta.8
 
 ## 5.0.0-beta.7

diff --git a/packages/vitest/package.json b/packages/vitest/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@unthrown/vitest",
-  "version": "5.0.0-beta.8",
+  "version": "5.0.0-beta.9",
   "description": "Vitest matchers for unthrown",
   "keywords": [
     "errors-as-values",