diff --git a/doc/knowledge_base/claude-driven-development.md b/doc/knowledge_base/claude-driven-development.md
index 8b882d0..d329c74 100644
--- a/doc/knowledge_base/claude-driven-development.md
+++ b/doc/knowledge_base/claude-driven-development.md
@@ -134,7 +134,7 @@ A single, project-independent bash helper provides four commands. It is the same
 - `cdd-worktree <branch>`, creates a worktree for `<branch>` and launches Claude Code in plan mode in it with the suggested first prompt already submitted. Requires a handoff file to exist.
 - `cdd-worktree-done`, run from a feature worktree once the PR has landed or the branch is being abandoned. Returns to the default branch, pulls, removes the worktree, resolves the branch (safe-delete if merged, force-delete if squash-merged, prompt otherwise), and deletes the handoff — and its sibling state record (§2.13) — iff the branch was deleted.
 - `cdd-worktree-list`, lists active handoffs with worktree/branch/PR status. Highlights stale entries.
-- `cdd-worktree-resume [<branch>]`, picks up a task started on another machine that has only a clone of the repo (no local branch, worktree, or handoff). It fetches `origin` and recreates a worktree tracking an **existing remote branch**, then `cd`s into it, ready for you to run a resume-side command (`/cdd-process-pr`, `/cdd-merge-base`, `/cdd-pre-pr`). With no argument it lists remote feature branches not already checked out and prompts for one. Its scope is deliberately **worktree and branch recreation only**: the handoff (§2.6) and the state record (§2.13) stay local per machine and are *not* transferred — sound, because the resume-side commands read PR/branch state from git and `gh`, not the handoff, and `cdd-state set` no-ops when the record is absent. Cross-machine *sync* of those two artifacts is separate, still-future work (issue #22); the direction is sketched in the roadmap.
+- `cdd-worktree-resume [<branch>]`, picks up a task started on another machine that has only a clone of the repo (no local branch, worktree, or handoff). It fetches `origin` and recreates a worktree tracking an **existing remote branch**, then `cd`s into it, ready for you to run a resume-side command (`/cdd-process-pr`, `/cdd-merge-base`, `/cdd-pre-pr`). With no argument it lists remote feature branches not already checked out and prompts for one; the fetch it runs first uses `--prune`, so branches deleted on the remote (as GitHub does when a PR merges) drop out of the list, leaving just the live branches — the default plus whatever feature branches still exist on the remote, whether or not they yet have a PR. Its scope is deliberately **worktree and branch recreation only**: the handoff (§2.6) and the state record (§2.13) stay local per machine and are *not* transferred — sound, because the resume-side commands read PR/branch state from git and `gh`, not the handoff, and `cdd-state set` no-ops when the record is absent. Cross-machine *sync* of those two artifacts is separate, still-future work (issue #22); the direction is sketched in the roadmap.
 
 The helper installs itself to a stable home that does not depend on a live CDD checkout. Run `tools/cdd-worktree.sh install` once (the script is dual-mode: sourced it defines the functions; run directly with `install` it sets itself up): this copies the script to `~/.cdd/tools/cdd-worktree.sh`, appends a marker-guarded source line to `~/.bashrc` and `~/.zshrc` (idempotent), drops thin PATH shims into `~/.local/bin` (one per command), and migrates any handoffs from the legacy `~/.claude-handoffs/` location. The PATH shims matter because the rc `source` line only reaches **interactive** shells — a stock `~/.bashrc` returns early for non-interactive shells via its `case $- in *i*` guard — so a command invoked from a non-interactive shell (notably Claude Code's Bash tool) would otherwise be "command not found"; the shim sources the helper and dispatches, while interactive shells still prefer the sourced function (functions shadow PATH, which is what lets `cdd-worktree` `cd` the caller into the new worktree). After installing, the commands work in every CDD project — including ones bootstrapped later — without any further per-project setup.
 
diff --git a/scripts/worktree-resume-assert.sh b/scripts/worktree-resume-assert.sh
index 028f659..d6b01ba 100755
--- a/scripts/worktree-resume-assert.sh
+++ b/scripts/worktree-resume-assert.sh
@@ -2,7 +2,7 @@
 # End-to-end smoke for `cdd-worktree-resume` (issue #22) against a local bare repo.
 #
 # The real cross-machine flow is hard to exercise in CI, so this stands in a local
-# `git init --bare` for `origin`: it pushes a default branch plus two feature
+# `git init --bare` for `origin`: it pushes a default branch plus three feature
 # branches, clones a fresh "machine B" working copy that has NO local feature
 # branch / worktree, then sources the helper and asserts:
 #   - `cdd-worktree-resume <branch>` creates a sibling worktree tracking
@@ -11,6 +11,10 @@
 #     returns 0
 #   - `cdd-worktree-resume` with no argument lists resumable remote branches and
 #     creates the selected one (fed a numbered choice on stdin)
+#   - discovery's `git fetch --prune` drops a branch deleted on the remote (as
+#     GitHub does on merge), so it does not appear in the list
+#   - explicit `cdd-worktree-resume <branch>` for a remote-deleted branch is
+#     refused and creates no worktree
 #
 # Usage: scripts/worktree-resume-assert.sh
 # Takes no arguments; it provisions and tears down its own temp tree. A stubbed
@@ -46,6 +50,10 @@ EOF
 DEFAULT_BRANCH="main"
 FEATURE_A="gh_issue_99_demo"
 FEATURE_B="gh_issue_100_other"
+# A branch that gets deleted on the remote (as GitHub does when a PR merges).
+# Discovery's `git fetch --prune` must drop it, and explicit resume must refuse
+# it. Sorts before A/B so it would be candidate 1 if pruning were missing.
+FEATURE_C="gh_issue_50_gone"
 
 # Stub `claude` on PATH as a negative guard: the helper must never invoke it, so
 # any output here (a non-empty log) is a regression.
@@ -73,6 +81,9 @@ git clone -q "$WORK/origin.git" "$WORK/seed" 2>/dev/null  # empty-repo warning i
   git switch -q -c "$FEATURE_B" "$DEFAULT_BRANCH"
   echo "b" > b.txt; git add b.txt; git commit -q -m "feature b"
   git push -q -u origin "$FEATURE_B"
+  git switch -q -c "$FEATURE_C" "$DEFAULT_BRANCH"
+  echo "c" > c.txt; git add c.txt; git commit -q -m "feature c"
+  git push -q -u origin "$FEATURE_C"
 )
 
 # Run the helper in a subshell so its `cd` and `set` don't leak into the test.
@@ -122,7 +133,8 @@ pass "already-exists resume returns 0 without launching claude"
 
 # 4. Discovery mode (no argument): pick the first listed branch via stdin.
 #    for-each-ref sorts refnames, so candidate 1 is the lexicographically first
-#    feature branch ($FEATURE_B = gh_issue_100_other sorts before $FEATURE_A).
+#    feature branch ($FEATURE_B = gh_issue_100_other sorts before $FEATURE_A;
+#    $FEATURE_C = gh_issue_50_gone sorts first but is not selected here).
 git clone -q "$WORK/origin.git" "$WORK/repoB"
 : > "$CLAUDE_STUB_LOG"
 set +e
@@ -136,4 +148,34 @@ head="$(git -C "$WT_B" rev-parse --abbrev-ref HEAD)"
 [[ "$head" == "$FEATURE_B" ]] || fail "discovery worktree HEAD is '$head', expected '$FEATURE_B'"
 pass "discovery mode resumed the selected remote branch"
 
+# 5. Discovery prunes branches deleted on the remote. Clone first (so the stale
+#    origin/$FEATURE_C ref exists locally), then delete the branch on origin, as
+#    GitHub does when a PR merges. Feed an invalid choice (0) so the helper prints
+#    the candidate list then bails without creating a worktree; inspect it.
+git clone -q "$WORK/origin.git" "$WORK/repoC"
+git -C "$WORK/seed" push -q origin --delete "$FEATURE_C"
+set +e
+list_out="$(run_resume "$WORK/repoC" "" "0" 2>/dev/null)"
+set -e
+grep -q "$FEATURE_A" <<<"$list_out" || fail "discovery should list live $FEATURE_A"
+grep -q "$FEATURE_B" <<<"$list_out" || fail "discovery should list live $FEATURE_B"
+if grep -q "$FEATURE_C" <<<"$list_out"; then
+  fail "discovery must prune $FEATURE_C after it was deleted on the remote"
+fi
+pass "discovery prunes branches deleted on the remote"
+
+# 6. Explicit resume of a remote-deleted branch is refused, and no worktree is
+#    created for it. repoC still carries the stale ref; the fetch --prune inside
+#    resume drops it, so show-ref then fails.
+: > "$CLAUDE_STUB_LOG"
+set +e
+run_resume "$WORK/repoC" "$FEATURE_C" "" >/dev/null 2>&1
+rc=$?
+set -e
+[[ "$rc" -ne 0 ]] || fail "explicit resume of remote-deleted $FEATURE_C should exit non-zero"
+[[ ! -d "$WORK/repoC-$FEATURE_C" ]] \
+  || fail "explicit resume of remote-deleted $FEATURE_C must not create a worktree"
+[[ ! -s "$CLAUDE_STUB_LOG" ]] || fail "refused resume must not launch claude"
+pass "explicit resume of a remote-deleted branch is refused without a worktree"
+
 echo "all worktree-resume smoke checks passed"
diff --git a/tools/cdd-worktree.sh b/tools/cdd-worktree.sh
index f31d18a..ae6f477 100755
--- a/tools/cdd-worktree.sh
+++ b/tools/cdd-worktree.sh
@@ -312,8 +312,11 @@ cdd-worktree-resume() {
     return 1
   fi
 
-  if ! git fetch origin; then
-    echo "git fetch origin failed, aborting." >&2
+  # --prune drops stale remote-tracking refs for branches deleted on the remote
+  # (GitHub deletes the head branch when a PR merges), so discovery lists exactly
+  # what still exists on origin — the default branch plus live feature branches.
+  if ! git fetch --prune origin; then
+    echo "git fetch --prune origin failed, aborting." >&2
     return 1
   fi
 
@@ -324,7 +327,8 @@ cdd-worktree-resume() {
 
   if [[ -z "$branch" ]]; then
     # Discovery: remote feature branches (exclude default + HEAD) not already
-    # checked out as a local worktree.
+    # checked out as a local worktree. The fetch above pruned merged-and-deleted
+    # branches, so what remains is the set of live branches shown on GitHub.
     local have_gh=0
     if command -v gh >/dev/null 2>&1 && gh auth status >/dev/null 2>&1; then
       have_gh=1
@@ -368,7 +372,8 @@ cdd-worktree-resume() {
     branch="${candidates[$(( choice - 1 ))]}"
   else
     if ! git show-ref --verify --quiet "refs/remotes/origin/$branch"; then
-      echo "No remote branch origin/$branch (after fetch)." >&2
+      echo "No remote branch origin/$branch (after fetch --prune)." >&2
+      echo "It may have been merged and deleted on the remote, or never pushed." >&2
       echo "Use 'cdd-worktree-resume' with no argument to list resumable branches." >&2
       return 1
     fi