diff --git a/.github/workflows/fork-check.yml b/.github/workflows/fork-check.yml
index c37fe9100b26..b1c2dd51e2e8 100644
--- a/.github/workflows/fork-check.yml
+++ b/.github/workflows/fork-check.yml
@@ -36,6 +36,9 @@ jobs:
           git sparse-checkout set --no-cone '/*' '!/.repos/'
           git -c checkout.workers=0 checkout -q --detach "$GITHUB_SHA"
 
+      - name: Test the release repair script
+        run: bash fork/resolve-merge.test.sh
+
       - name: Setup Vite+
         uses: voidzero-dev/setup-vp@250f29ce396baf5e8f24498e17c0dfdebabc26eb # v1
         with:
diff --git a/FORK.md b/FORK.md
index 20337418cf54..785aa78340bd 100644
--- a/FORK.md
+++ b/FORK.md
@@ -68,8 +68,11 @@ side calls what the other renamed) or broken on `collin/main` itself. Fixes go i
 only. It needs the repository secret `CLAUDE_CODE_OAUTH_TOKEN` (from `claude setup-token`; bills
 the subscription's monthly Agent SDK credit) or `ANTHROPIC_API_KEY` (Console API credits; wins
 when both are set). Each fork/upstream pair is checked once and cached, so retries cost nothing.
-When Claude cannot make it typecheck, the run fails: sync `collin/main` by hand, then
-`gh workflow run fork-release.yml` (`-f force=true` asks Claude again instead).
+When Claude cannot make it typecheck, the run fails. The T3 scheduled task "Fork repair" looks for
+a red `Fork release` or `Fork check` on `collin/main` every four hours, fixes the cause in a pull
+request and merges it once `Fork check` is green; it needs the machine with T3 Code running. By
+hand: sync `collin/main`, then `gh workflow run fork-release.yml` (`-f force=true` asks Claude
+again instead).
 
 Pull requests into `collin/main` and pushes to it run `.github/workflows/fork-check.yml` (frozen
 install and the same typecheck). Upstream's CI needs Blacksmith runners a fork does not have; its
diff --git a/fork/resolve-merge.sh b/fork/resolve-merge.sh
index c7af190c6df5..a9e00092bff5 100755
--- a/fork/resolve-merge.sh
+++ b/fork/resolve-merge.sh
@@ -90,6 +90,26 @@ VP_GIT_HOOKS=0 vp install
 # typecheck. Claude fixes what the typecheck reports, in the files it names. Same apps as the
 # desktop build bundles.
 broken=()
+# The tracked files a typecheck log blames, from the repository root. tsc paths are relative to the
+# app, and the layout depends on the tool and on whether it prints to a terminal:
+# src/x.ts(12,5): error TS... or src/x.ts:12:5 - error TS...
+# A layout nothing here knows must still reach Claude, so any path on an error line counts.
+blamed_files() {
+  local app=$1 log_file=$2 text paths path
+  text=$(sed 's/\x1b\[[0-9;]*m//g' "$log_file")
+  paths=$(grep -oE '^[^ :(]+\.[cm]?tsx?(\([0-9]+,[0-9]+\):|:[0-9]+:[0-9]+ -) error' <<<"$text" |
+    sed -E 's/[(:].*$//' || true)
+  if [[ -z "$paths" ]]; then
+    paths=$(grep -E 'error TS[0-9]+' <<<"$text" | grep -oE '[^ :(]+\.[cm]?tsx?' || true)
+  fi
+  for path in $(sort -u <<<"$paths"); do
+    path=$(realpath -m --relative-to=. "apps/$app/$path")
+    if git ls-files --error-unmatch -- "$path" > /dev/null 2>&1; then
+      echo "$path"
+    fi
+  done
+}
+
 typecheck() {
   local app status=0
   broken=()
@@ -97,10 +117,7 @@ typecheck() {
   for app in server desktop web; do
     if ! (cd "apps/$app" && vp run typecheck) > "$log.$app" 2>&1; then
       status=1
-      # tsc prints paths relative to the app: src/x.ts:12:5 - error TS...
-      mapfile -t -O "${#broken[@]}" broken < <(sed 's/\x1b\[[0-9;]*m//g' "$log.$app" |
-        grep -oE '^[^ :(]+\.[cm]?tsx?:[0-9]+:[0-9]+ - error' |
-        cut -d: -f1 | sort -u | sed "s|^|apps/$app/|")
+      mapfile -t -O "${#broken[@]}" broken < <(blamed_files "$app" "$log.$app")
     fi
     cat "$log.$app" >> "$log"
   done
@@ -149,7 +166,12 @@ if ! typecheck; then
   exit 1
 fi
 
-git add -A -- "${files[@]}" "${fixable[@]}"
+# git rm already staged a deleted conflict file, and git add refuses a path that is gone.
+for file in "${files[@]}" "${fixable[@]}"; do
+  if [[ -e "$file" ]] || git ls-files --error-unmatch -- "$file" > /dev/null 2>&1; then
+    git add -A -- "$file"
+  fi
+done
 if git rev-parse -q --verify MERGE_HEAD > /dev/null; then
   git commit -q --no-edit
 elif ! git diff --cached --quiet; then
diff --git a/fork/resolve-merge.test.sh b/fork/resolve-merge.test.sh
new file mode 100644
index 000000000000..68a32f0f55cd
--- /dev/null
+++ b/fork/resolve-merge.test.sh
@@ -0,0 +1,89 @@
+#!/usr/bin/env bash
+# Runs fork/resolve-merge.sh against throwaway repositories with stubbed vp and claude. Its repair
+# path only runs when a release is already broken, so a regression there stays silent until then.
+set -euo pipefail
+
+script=$(realpath "$(dirname "$0")/resolve-merge.sh")
+root=$(mktemp -d)
+trap 'rm -rf "$root"' EXIT
+failed=0
+
+mkdir "$root/bin"
+# Reports whatever $TSC_LINE says while the file it names (relative to the app) holds BROKEN.
+cat > "$root/bin/vp" <<'STUB'
+#!/usr/bin/env bash
+[[ "$1" == run && "$(basename "$PWD")" == server ]] || exit 0
+if grep -rqs BROKEN src ../../packages; then
+  printf '~/apps/server$ tsc --noEmit\n%b\n' "$TSC_LINE"
+  exit 2
+fi
+STUB
+cat > "$root/bin/claude" <<'STUB'
+#!/usr/bin/env bash
+for file in $(git diff --name-only --diff-filter=U); do git rm -q -f -- "$file"; done
+grep -rl BROKEN apps packages | xargs -r sed -i 's/BROKEN/fixed/'
+STUB
+chmod +x "$root/bin/vp" "$root/bin/claude"
+export PATH="$root/bin:$PATH" CLAUDE_CODE_OAUTH_TOKEN=test
+
+new_repo() {
+  git init -q -b base "$1"
+  git -C "$1" config user.name test
+  git -C "$1" config user.email test@example.com
+  mkdir -p "$1"/apps/{server,desktop,web}/src "$1/packages/shared/src"
+  touch "$1/pnpm-lock.yaml" "$1"/apps/{server,desktop,web}/src/keep.ts
+}
+
+report() {
+  if [[ "$2" == 0 ]]; then
+    echo "ok: $1"
+  else
+    echo "FAILED: $1"
+    cat "$root/output" || true
+    failed=1
+  fi
+}
+
+check_repair() {
+  local name=$1 path=$2 line=$3 repo status=0
+  repo="$root/repo$RANDOM"
+  new_repo "$repo"
+  echo "const x = BROKEN;" > "$repo/$path"
+  git -C "$repo" add -A
+  git -C "$repo" commit -qm base
+  (cd "$repo" && RUNNER_TEMP="$root" TSC_LINE="$line" bash "$script") > "$root/output" 2>&1 || status=1
+  if [[ $status == 0 && "$(git -C "$repo" show "HEAD:$path")" != "const x = fixed;" ]]; then
+    status=1
+  fi
+  grep -qxF "Typecheck round 1 failed in: $path" "$root/output" || status=1
+  report "$name" "$status"
+}
+
+# Names a second file, so only the path at the start of the line may count.
+error="error TS2304: Cannot find name 'BROKEN' from src/keep.ts."
+check_repair "parenthesized errors reach Claude" apps/server/src/a.ts "src/a.ts(1,11): $error"
+check_repair "pretty errors reach Claude" apps/server/src/a.ts "\033[96msrc/a.ts\033[0m:1:11 - $error"
+check_repair "errors in a package reach Claude" packages/shared/src/a.ts "../../packages/shared/src/a.ts(1,11): $error"
+check_repair "an unknown layout still reaches Claude" apps/server/src/a.ts "error TS2304 in src/a.ts"
+
+# A modify/delete conflict Claude settles with git rm must not break the commit.
+repo="$root/deleted"
+new_repo "$repo"
+echo one > "$repo/apps/web/src/gone.ts"
+git -C "$repo" add -A
+git -C "$repo" commit -qm base
+git -C "$repo" checkout -qb upstream
+git -C "$repo" rm -q apps/web/src/gone.ts
+git -C "$repo" commit -qm "upstream deletes"
+git -C "$repo" checkout -q base
+echo two > "$repo/apps/web/src/gone.ts"
+git -C "$repo" commit -qam "fork edits"
+git -C "$repo" merge -q --no-commit --no-ff upstream > /dev/null 2>&1 || true
+status=0
+(cd "$repo" && RUNNER_TEMP="$root" TSC_LINE="" bash "$script") > "$root/output" 2>&1 || status=1
+if [[ $status == 0 && "$(git -C "$repo" rev-list --parents -n 1 HEAD | wc -w)" != 3 ]]; then
+  status=1
+fi
+report "a conflict settled with git rm commits the merge" "$status"
+
+exit "$failed"