diff --git a/CHANGELOG.md b/CHANGELOG.md
index d09e7f699..9eb529625 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Registry plugins built before 0.49.0 install and load again instead of failing with an invalid plugin bundle error.
+
 ## [0.49.0] - 2026-06-06
 
 ### Added
diff --git a/CLAUDE.md b/CLAUDE.md
index db6bf2a64..e10e1ca06 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -104,6 +104,8 @@ When adding a new method to the driver protocol: add to `PluginDatabaseDriver` (
 
 **Additive changes are binary-compatible and need NO version bump**: adding a requirement to `DriverPlugin` / `PluginDatabaseDriver` that has a default implementation, reordering requirements, adding a field to a non-`@frozen` transfer struct, or removing a requirement that defaulted to `nil`.
 
+**Adding a field to a transfer struct is additive ONLY if every existing public initializer keeps its exact signature.** Adding a parameter to an existing public init or function, even with a default value, replaces its mangled symbol and breaks every already-built plugin (this shipped in 0.49.0: `PluginQueryResult` gained `columnMeta:` on its init and every registry plugin failed to load with "Bundle failed to load executable"). Add a NEW overload for the new field and keep the old signature; mark the old overload `@_disfavoredOverload` so new code resolves to the full init while old binaries keep their symbol. A red PluginKit ABI Gate is a merge blocker, never something to merge over: either the diff is additive (verify no symbol disappeared, then add the `abi-additive` label) or it is breaking (bump and re-release).
+
 **Bump `currentPluginKitVersion` (in `PluginManager.swift`) and `TableProPluginKitVersion` in every plugin `Info.plist` ONLY for a breaking change**: changing or removing an existing requirement's signature, adding a requirement without a default, adding a case to a `@frozen` enum, or changing a frozen type's layout. Mark a public enum `@frozen` only when an exhaustive switch over it forces it (the compiler flags the switch) and its case set is genuinely closed; leave the rest non-frozen so they can gain cases. `PluginCapability` stays non-frozen with `@unknown default` because it is a growing capability set, not a closed vocabulary. The driver protocols and transfer structs stay non-frozen so they can grow. The strict version gate in `validateBundleVersions` still rejects a stale plugin cleanly after a breaking bump (no `EXC_BAD_INSTRUCTION`).
 
 **ABI gate**: `scripts/check-pluginkit-abi.sh [base-ref]` builds TableProPluginKit at the current tree and at the base ref with the same toolchain, then diffs their public interfaces. There is no committed baseline, so a Swift version difference between a dev machine and CI never produces a false diff. CI (`.github/workflows/pluginkit-abi.yml`) runs it on every PR that touches `Plugins/TableProPluginKit/**`, comparing against the PR base. A reported diff is a real ABI change: additive needs no bump; breaking needs the version bump above plus `release-all-plugins.sh`. After reviewing a diff as additive, add the `abi-additive` label to the PR; the gate then passes and records the decision. Remove the label if later commits add a breaking change. (Until Library Evolution is on the base too, the base emits no interface and the gate passes as a bootstrap.)
diff --git a/Plugins/TableProPluginKit/PluginQueryResult.swift b/Plugins/TableProPluginKit/PluginQueryResult.swift
index 474a16629..d2d69ad1a 100644
--- a/Plugins/TableProPluginKit/PluginQueryResult.swift
+++ b/Plugins/TableProPluginKit/PluginQueryResult.swift
@@ -30,6 +30,28 @@ public struct PluginQueryResult: Codable, Sendable {
         self.columnMeta = columnMeta
     }
 
+    @_disfavoredOverload
+    public init(
+        columns: [String],
+        columnTypeNames: [String],
+        rows: [[PluginCellValue]],
+        rowsAffected: Int,
+        executionTime: TimeInterval,
+        isTruncated: Bool,
+        statusMessage: String?
+    ) {
+        self.init(
+            columns: columns,
+            columnTypeNames: columnTypeNames,
+            rows: rows,
+            rowsAffected: rowsAffected,
+            executionTime: executionTime,
+            isTruncated: isTruncated,
+            statusMessage: statusMessage,
+            columnMeta: nil
+        )
+    }
+
     public static let empty = PluginQueryResult(
         columns: [],
         columnTypeNames: [],