diff --git a/.github/workflows/daily_ai_fix.yaml b/.github/workflows/daily_ai_fix.yaml
index e3199b6ce1..6d832a0d23 100644
--- a/.github/workflows/daily_ai_fix.yaml
+++ b/.github/workflows/daily_ai_fix.yaml
@@ -178,4 +178,15 @@ jobs:
         env:
           GH_TOKEN: ${{ secrets.AI_PR_TOKEN }}
           REPO: ${{ github.repository }}
-        run: bash .github/scripts/ai_guard_paths.sh
+        run: |
+          set -euo pipefail
+          # Run the guard from the trusted default-branch copy, never the in-tree
+          # copy the model could have modified in this same job.
+          DEFAULT=$(gh api "repos/${REPO}" --jq '.default_branch' 2>/dev/null || echo master)
+          if git fetch --depth=1 origin "$DEFAULT" >/dev/null 2>&1 \
+             && git cat-file -e "FETCH_HEAD:.github/scripts/ai_guard_paths.sh" 2>/dev/null; then
+            git show "FETCH_HEAD:.github/scripts/ai_guard_paths.sh" | bash
+          else
+            echo "::warning::trusted guard copy unavailable, using in-tree copy"
+            bash .github/scripts/ai_guard_paths.sh
+          fi
diff --git a/.github/workflows/daily_stale.yml b/.github/workflows/daily_stale.yml
index 6a316d8d39..d0b669180c 100644
--- a/.github/workflows/daily_stale.yml
+++ b/.github/workflows/daily_stale.yml
@@ -32,5 +32,5 @@ jobs:
         # AI triage labels are exempt: an issue waiting on @alexbelgium's
         # `ai:approved`, or queued for the tier-2 sweep, must not be auto-closed
         # out from under the pipeline before it is acted on.
-        exempt-issue-labels: 'prevent stale,ai-triage,ai:plan-pending,ai:needs-info,ai:needs-human'
+        exempt-issue-labels: 'prevent stale,ai-triage,ai:plan-pending,ai:approved,ai:needs-info,ai:needs-human'
         remove-stale-when-updated: true
diff --git a/.github/workflows/on_issue_approved.yaml b/.github/workflows/on_issue_approved.yaml
index 01a70cf089..62427a8b30 100644
--- a/.github/workflows/on_issue_approved.yaml
+++ b/.github/workflows/on_issue_approved.yaml
@@ -62,9 +62,13 @@ jobs:
             "The \`ai:approved\` label only takes effect when applied by @alexbelgium; removing it."
 
   execute:
+    # workflow_dispatch is a maintainer override, so it must also be gated to
+    # @alexbelgium — otherwise any collaborator with run-workflow rights could
+    # execute a Tier 3 plan without the approval label or sender check.
     if: >-
       vars.AI_DISABLED != 'true' &&
-      ( github.event_name == 'workflow_dispatch' ||
+      ( ( github.event_name == 'workflow_dispatch' &&
+          github.actor == 'alexbelgium' ) ||
         ( github.event.label.name == 'ai:approved' &&
           github.event.sender.login == 'alexbelgium' ) )
     runs-on: ubuntu-latest
@@ -103,14 +107,28 @@ jobs:
           mkdir -p /tmp/ai-exec
           gh issue view "$ISSUE" --repo "$REPO" \
             --json number,title,body,author,labels,comments > /tmp/ai-exec/issue.json
-          # The plan is the most recent comment carrying the ai-plan marker.
-          jq -r '[.comments[] | select(.body | contains("<!-- ai-plan -->"))]
+          # The plan is the most recent ai-plan comment FROM A TRUSTED AUTHOR.
+          # The marker alone is not proof of origin: any reporter can paste
+          # "<!-- ai-plan -->" into a comment, and picking it by marker+last
+          # would let them swap in a plan that then executes on approval.
+          # Tier 2 posts under AI_PR_TOKEN, whose identity is a repo OWNER/
+          # MEMBER/COLLABORATOR; a reporter is never one of those. (If you
+          # switch AI_PR_TOKEN to a GitHub App, add its bot login here.)
+          jq -r '[.comments[]
+                  | select((.body | contains("<!-- ai-plan -->"))
+                           and (.authorAssociation == "OWNER"
+                                or .authorAssociation == "MEMBER"
+                                or .authorAssociation == "COLLABORATOR"))]
                  | last | .body // ""' /tmp/ai-exec/issue.json > /tmp/ai-exec/plan.md
           if [ ! -s /tmp/ai-exec/plan.md ]; then
             echo "has_plan=false" >> "$GITHUB_OUTPUT"
-            echo "::warning::no <!-- ai-plan --> comment on issue #$ISSUE; nothing to execute"
+            echo "::warning::no trusted <!-- ai-plan --> comment on issue #$ISSUE; nothing to execute"
+            # Consume the approval here too, so a later real plan can be
+            # re-approved (re-adding ai:approved to an issue that still carries
+            # it would not fire a fresh labeled event).
+            gh issue edit "$ISSUE" --repo "$REPO" --remove-label ai:approved >/dev/null 2>&1 || true
             gh issue comment "$ISSUE" --repo "$REPO" --body \
-              "No AI plan (\`<!-- ai-plan -->\`) was found on this issue, so \`ai:approved\` has nothing to execute. Run the tier-2 sweep on it first (\`AI fix sweep\` → issue $ISSUE)."
+              "No AI plan (\`<!-- ai-plan -->\`) from the triage bot was found on this issue, so \`ai:approved\` has nothing to execute (removed). Run the tier-2 sweep on it first (\`AI fix sweep\` → issue $ISSUE), then approve the plan it posts."
           else
             echo "has_plan=true" >> "$GITHUB_OUTPUT"
             echo "plan: $(wc -c < /tmp/ai-exec/plan.md) bytes"
@@ -161,4 +179,15 @@ jobs:
         env:
           GH_TOKEN: ${{ secrets.AI_PR_TOKEN }}
           REPO: ${{ github.repository }}
-        run: bash .github/scripts/ai_guard_paths.sh
+        run: |
+          set -euo pipefail
+          # Run the guard from the trusted default-branch copy, never the in-tree
+          # copy the model could have modified in this same job.
+          DEFAULT=$(gh api "repos/${REPO}" --jq '.default_branch' 2>/dev/null || echo master)
+          if git fetch --depth=1 origin "$DEFAULT" >/dev/null 2>&1 \
+             && git cat-file -e "FETCH_HEAD:.github/scripts/ai_guard_paths.sh" 2>/dev/null; then
+            git show "FETCH_HEAD:.github/scripts/ai_guard_paths.sh" | bash
+          else
+            echo "::warning::trusted guard copy unavailable, using in-tree copy"
+            bash .github/scripts/ai_guard_paths.sh
+          fi
diff --git a/.github/workflows/on_issues_ai_triage.yaml b/.github/workflows/on_issues_ai_triage.yaml
index e3af1cbf10..e7ff3fd19c 100644
--- a/.github/workflows/on_issues_ai_triage.yaml
+++ b/.github/workflows/on_issues_ai_triage.yaml
@@ -80,16 +80,33 @@ jobs:
     environment: CR_PAT
 
     steps:
-      # The reply that re-triggered this run consumes the needs-info flag, so a
-      # later comment on the same thread cannot re-run tier 1 again. apply-verdict
-      # re-adds it only if the issue still lacks the info (one more round).
-      - name: Consume needs-info flag
+      # A reporter reply re-triggered this run. Multiple replies can each pass
+      # the job `if` before the first run clears the flag; cancel-in-progress
+      # is false, so without this they would each run a full classification.
+      # Re-check the LIVE label inside the serialized job and consume it here:
+      # the first queued run finds it present and proceeds (go=true); any run
+      # behind it finds it already gone and skips every downstream step.
+      # apply-verdict re-adds the flag if the issue still needs info (one more
+      # round), or restores it if no verdict was produced (so a later reply can
+      # still retry instead of the issue silently dropping out).
+      - name: Claim needs-info reply
+        id: claim
         if: github.event_name == 'issue_comment'
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           ISSUE: ${{ github.event.issue.number }}
           REPO: ${{ github.repository }}
-        run: gh issue edit "$ISSUE" --repo "$REPO" --remove-label ai:needs-info || true
+        run: |
+          set -euo pipefail
+          HAS=$(gh issue view "$ISSUE" --repo "$REPO" --json labels \
+                --jq '[.labels[].name] | index("ai:needs-info") != null')
+          if [ "$HAS" != "true" ]; then
+            echo "ai:needs-info already consumed by an earlier queued run; skipping"
+            echo "go=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+          gh issue edit "$ISSUE" --repo "$REPO" --remove-label ai:needs-info || true
+          echo "go=true" >> "$GITHUB_OUTPUT"
 
       # on_issues_ping_submitter.yml has to land first: the classifier reads
       # the existing comments and bails out if someone already owns the issue.
@@ -102,7 +119,11 @@ jobs:
         if: github.event_name == 'issues'
         run: sleep 60
 
+      # Skip everything below for a needs-info reply that was already consumed
+      # by an earlier queued run (steps.claim.go == false). Non-comment events
+      # (issues.opened, dispatch) never set claim, so they always proceed.
       - name: Checkout tooling
+        if: github.event_name != 'issue_comment' || steps.claim.outputs.go == 'true'
         uses: actions/checkout@fbc6f3992d24b796d5a048ff273f7fcc4a7b6c09  # v5
         with:
           fetch-depth: 1
@@ -113,6 +134,7 @@ jobs:
           sparse-checkout-cone-mode: false
 
       - name: Build context bundle
+        if: github.event_name != 'issue_comment' || steps.claim.outputs.go == 'true'
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           ISSUE_NUMBER: ${{ github.event.issue.number || inputs.issue }}
@@ -121,6 +143,7 @@ jobs:
 
       - name: Classify
         id: classify
+        if: github.event_name != 'issue_comment' || steps.claim.outputs.go == 'true'
         continue-on-error: true
         uses: anthropics/claude-code-action@44423bdec74b97d67543eb16c110546762c110b2  # v1
         with:
@@ -142,15 +165,23 @@ jobs:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Apply verdict
+        if: github.event_name != 'issue_comment' || steps.claim.outputs.go == 'true'
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           ISSUE: ${{ github.event.issue.number || inputs.issue }}
           REPO: ${{ github.repository }}
+          EVENT_NAME: ${{ github.event_name }}
         run: |
           set -euo pipefail
           F=/tmp/ai-triage/verdict.json
           if [ ! -s "$F" ] || ! jq -e . "$F" >/dev/null 2>&1; then
             echo "::warning::no usable verdict produced, leaving issue untouched"
+            # A reporter reply consumed ai:needs-info in the claim step above.
+            # With no verdict we would otherwise leave the issue with the flag
+            # gone, so the next reply could never re-trigger — restore it.
+            if [ "${EVENT_NAME:-}" = "issue_comment" ]; then
+              gh issue edit "$ISSUE" --repo "$REPO" --add-label ai:needs-info >/dev/null 2>&1 || true
+            fi
             exit 0
           fi
 
@@ -258,17 +289,21 @@ jobs:
         run: |
           set -euo pipefail
           NOW=$(date -u +%s)
-          gh issue list --repo "$REPO" --state open --limit 100 \
-            --json number,createdAt,author,labels > /tmp/catchup.json
-          # Untriaged = no ai:* / ai-triage / no-ai label, not the maintainer's
-          # own issue, and older than 2h (so a just-opened issue whose tier-1
-          # run is still in flight is not double-dispatched). Cap 5 per day.
+          # Filter untriaged issues SERVER-SIDE so the total open-issue count is
+          # irrelevant (a plain --limit would silently drop everything past the
+          # cap, and gh lists newest-first). The search excludes every ai:* /
+          # ai-triage / no-ai label, so what comes back is already the candidate
+          # set; newest 50 is far more than the daily cap of 5.
+          gh issue list --repo "$REPO" --limit 50 \
+            --search 'is:open sort:created-desc -label:ai-triage -label:"ai:classified" -label:"ai:needs-info" -label:"ai:needs-human" -label:"ai:plan-pending" -label:"ai:approved" -label:"ai:fixed" -label:"ai:upstream" -label:no-ai' \
+            --json number,createdAt,author > /tmp/catchup.json
+          # Not the maintainer's own issue, and older than 2h (so a just-opened
+          # issue whose tier-1 run is still in flight is not double-dispatched).
+          # Cap 5 per day.
           jq -r --argjson now "$NOW" '
             .[]
             | select(.author.login != "alexbelgium")
             | select((.createdAt | fromdateiso8601) < ($now - 7200))
-            | select([.labels[].name]
-                | any(. == "no-ai" or . == "ai-triage" or startswith("ai:")) | not)
             | .number' /tmp/catchup.json | head -n 5 > /tmp/todo.txt
 
           COUNT=$(grep -c . /tmp/todo.txt || true)
diff --git a/.github/workflows/on_pr_coderabbit.yml b/.github/workflows/on_pr_coderabbit.yml
index ded9c9c372..95a17f0cb4 100644
--- a/.github/workflows/on_pr_coderabbit.yml
+++ b/.github/workflows/on_pr_coderabbit.yml
@@ -103,4 +103,15 @@ jobs:
           GH_TOKEN: ${{ secrets.AI_PR_TOKEN }}
           REPO: ${{ github.repository }}
           PR_NUMBER: ${{ github.event.pull_request.number }}
-        run: bash .github/scripts/ai_guard_paths.sh
+        run: |
+          set -euo pipefail
+          # Run the guard from the trusted default-branch copy, never the in-tree
+          # copy on the PR branch the model just pushed to.
+          DEFAULT=$(gh api "repos/${REPO}" --jq '.default_branch' 2>/dev/null || echo master)
+          if git fetch --depth=1 origin "$DEFAULT" >/dev/null 2>&1 \
+             && git cat-file -e "FETCH_HEAD:.github/scripts/ai_guard_paths.sh" 2>/dev/null; then
+            git show "FETCH_HEAD:.github/scripts/ai_guard_paths.sh" | bash
+          else
+            echo "::warning::trusted guard copy unavailable, using in-tree copy"
+            bash .github/scripts/ai_guard_paths.sh
+          fi