diff --git a/.github/workflows/nightly.yml b/.github/workflows/nightly.yml
index a9de790..2dac0c6 100644
--- a/.github/workflows/nightly.yml
+++ b/.github/workflows/nightly.yml
@@ -7,9 +7,10 @@
 #
 # native-regression runs `native diff --record` on each main commit not yet
 # recorded and judges each line against the one before it. native-record
-# appends the lines to the `regression-data` branch. Cost is judged only
-# between a parent and its child measured one after the other in the same
-# job, never against a number from another runner.
+# appends the lines to the `regression-data` branch and files an issue for
+# each regression. Cost is judged only between a parent and its child
+# measured one after the other in the same job, never against a number from
+# another runner.
 #
 # Throughput is not benchmarked here. A shared runner cannot give the timing a
 # quiet machine gives. Run `bench-canonical-throughput` on a quiet box instead.
@@ -32,6 +33,10 @@ on:
       max_commits:
         description: "Main commits native-regression walks after the last recorded one"
         default: "8"
+      inject_regression:
+        description: "Also judge a copy of the night's last line with its refusal one tic earlier, and file what that finds"
+        type: boolean
+        default: false
 
 concurrency:
   group: nightly-${{ github.ref }}
@@ -132,8 +137,27 @@ jobs:
           CLICKDOOM_DATABASE: regress
         run: scripts/native-regression-walk.sh "$RUNNER_TEMP/history.jsonl" regression
       - name: Judge the night
+        env:
+          INJECT: ${{ github.event.inputs.inject_regression || 'false' }}
+          RUN_URL: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
         run: |
-          if [ ! -s regression/night.jsonl ]; then
+          judged=regression/night.jsonl
+          if [ "$INJECT" = true ]; then
+            # The last measured line, tonight's or the history's, under a
+            # commit that is not one, with its first refusal one tic earlier.
+            cat "$RUNNER_TEMP/history.jsonl" regression/night.jsonl \
+                | jq -c 'select(.error == null)' | tail -n 1 \
+                | jq -c --arg commit "self-test-$GITHUB_RUN_ID" \
+                    '.commit = $commit | .first_refused_tic = ((.first_refused_tic // 2001) - 1)' \
+                    >regression/injected.jsonl
+            if [ ! -s regression/injected.jsonl ]; then
+              echo "::error::no measured line to inject a regression into"
+              exit 1
+            fi
+            cat regression/night.jsonl regression/injected.jsonl >regression/judged.jsonl
+            judged=regression/judged.jsonl
+          fi
+          if [ ! -s "$judged" ]; then
             echo "nothing walked, so nothing to judge"
             exit 0
           fi
@@ -142,13 +166,19 @@ jobs:
             history=(--history "$RUNNER_TEMP/history.jsonl")
           fi
           status=0
-          "$RUNNER_TEMP/clickdoom-judge" native regress regression/night.jsonl "${history[@]}" \
-              || status=$?
-          case "$status" in
-            0) ;;
-            3) echo "::warning::a recorded line regressed; the lines above name it" ;;
-            *) exit "$status" ;;
-          esac
+          "$RUNNER_TEMP/clickdoom-judge" native regress "$judged" "${history[@]}" \
+              --findings regression/findings.jsonl || status=$?
+          if [ "$status" -ne 0 ] && [ "$status" -ne 3 ]; then
+            exit "$status"
+          fi
+          if [ "$INJECT" = true ] \
+              && ! jq -e --arg commit "self-test-$GITHUB_RUN_ID" 'select(.commit == $commit)' \
+                  regression/findings.jsonl >/dev/null; then
+            echo "::error::the injected regression was not found"
+            exit 1
+          fi
+          cat "$RUNNER_TEMP/history.jsonl" "$judged" >regression/lines.jsonl
+          scripts/native-regression-issues.sh regression/findings.jsonl regression/lines.jsonl regression/issues
       - name: Upload what the night found
         if: ${{ !cancelled() }}
         uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
@@ -158,12 +188,14 @@ jobs:
           if-no-files-found: error
 
   native-record:
-    # Writes the branch, and runs no repository code: it checks nothing out,
-    # and reads only the artifact native-regression uploaded.
+    # Writes the branch and the issues, and runs no repository code: it
+    # checks nothing out, and reads only the artifact native-regression
+    # uploaded.
     needs: native-regression
     runs-on: ubuntu-latest
     permissions:
       contents: write # appends to the regression-data branch
+      issues: write # files an issue for each regression
     timeout-minutes: 10
     env:
       GH_TOKEN: ${{ github.token }}
@@ -220,3 +252,33 @@ jobs:
                 -f ref="refs/heads/$REGRESSION_BRANCH" -f sha="$commit"
           fi
           echo "recorded $count line(s) on $REGRESSION_BRANCH"
+      - name: File an issue for each regression
+        run: |
+          shopt -s nullglob
+          failed=0
+          for dir in regression/issues/*/; do
+            title=$(cat "$dir/title")
+            # The title ends with the metric and the commit in parentheses.
+            marker="(${title##*(}"
+            filed=$(gh issue list --repo "$REPO" --state all --limit 20 \
+                --search "\"$marker\" in:title" --json number,title \
+                | jq -r --arg marker "$marker" '[.[] | select(.title | endswith($marker)) | .number] | first // empty')
+            if [ -n "$filed" ]; then
+              echo "already filed as #$filed: $title"
+              continue
+            fi
+            labels=()
+            while IFS= read -r label; do
+              labels+=(--label "$label")
+            done <"$dir/labels"
+            url=$(gh issue create --repo "$REPO" --title "$title" --body-file "$dir/body.md" "${labels[@]}")
+            echo "filed $url: $title"
+            # A label the token may not apply is dropped without an error.
+            want=$(sort "$dir/labels" | paste -sd, -)
+            got=$(gh issue view "$url" --json labels --jq '[.labels[].name] | sort | join(",")')
+            if [ "$got" != "$want" ]; then
+              echo "::error::$url carries labels '$got', not '$want'"
+              failed=1
+            fi
+          done
+          exit "$failed"
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 8661b34..6fb63bc 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -49,9 +49,9 @@ differential smoke.
 
 It is necessary and not sufficient. The nightly deep-diff is the only run that
 compares memory, and no pull request makes it. The nightly also diffs native
-mode against the reference emulator on each new main commit, and names the
-commit whose first refusal or first divergence moved earlier, or whose tic
-statement got slower than its parent's.
+mode against the reference emulator on each new main commit, and files an issue
+naming the commit whose first refusal or first divergence moved earlier, or
+whose tic statement got slower than its parent's.
 
 Check by exit code. A pipeline reports only its last command's status, so
 `make gates | tail` can hide a failure.
diff --git a/DEVELOPING.md b/DEVELOPING.md
index 7087e62..aab40da 100644
--- a/DEVELOPING.md
+++ b/DEVELOPING.md
@@ -195,9 +195,15 @@ last recorded commit again first.
 
 The `native-record` job appends the new lines to
 `native/bench/regression/results.jsonl` on the `regression-data` branch, which
-is never merged into main. It is the only job with write access, and it runs no
-repository code. With `max_commits` at 0 the walk measures only the last
-recorded commit.
+is never merged into main. It files an issue from `1b-native-divergence.yml` for
+a correctness regression and from `3-performance.yml` for a cost one, once per
+metric and commit. It is the only job with write access, and it runs no
+repository code.
+
+Dispatching the nightly with `inject_regression` judges one more line: a copy of
+the last measured line, with its refusal one tic earlier, under the commit name
+`self-test-<run id>`. The issue it files says so. The copy is not recorded.
+With `max_commits` at 0 the walk measures only the last recorded commit.
 
 The walk runs locally against `make up`:
 `scripts/native-regression-walk.sh HISTORY OUT`, with `HISTORY` a copy of the
diff --git a/scripts/native-regression-issues.sh b/scripts/native-regression-issues.sh
new file mode 100755
index 0000000..7532eb6
--- /dev/null
+++ b/scripts/native-regression-issues.sh
@@ -0,0 +1,153 @@
+#!/usr/bin/env bash
+#
+# Renders each regression `clickdoom native regress --findings` wrote as an
+# issue body, in the shape GitHub gives an issue filed through the form.
+#
+#   scripts/native-regression-issues.sh FINDINGS LINES OUT
+#
+# FINDINGS is the --findings file. LINES holds every recorded line either
+# side of a finding names, history and the night together. For finding N,
+# OUT/N/ gets `title`, `labels` (one per line) and `body.md`. A correctness
+# finding follows .github/ISSUE_TEMPLATE/1b-native-divergence.yml and a cost
+# finding .github/ISSUE_TEMPLATE/3-performance.yml, with each field's label
+# as a `###` heading.
+#
+# A title ends with the metric and the commit in parentheses, which is what
+# the filing job searches for before filing, so a regression is filed once.
+# A finding whose commit starts with `self-test-` was injected on purpose,
+# and its title and body say so.
+#
+# Environment:
+#   RUN_URL      the workflow run, linked from the body
+#   SEARCH_TICS  the first diff's span, for the reproduction
+set -euo pipefail
+cd "$(dirname "$0")/.."
+
+if [ "$#" -ne 3 ]; then
+    echo "usage: $0 FINDINGS LINES OUT" >&2
+    exit 2
+fi
+findings=$1
+lines=$2
+out=$3
+run_url=${RUN_URL:-}
+search_tics=${SEARCH_TICS:-2000}
+wad_sha=$(cut -d' ' -f1 rom/wad/doom1.wad.sha256sum)
+
+# The recorded line for COMMIT, the last one if it was measured twice.
+line_of() {
+    jq -c --arg commit "$1" 'select(.commit == $commit)' "$lines" | tail -n 1
+}
+
+# The form's "What disagrees" option for a field named as `kind slot n field`.
+what_disagrees() {
+    case "$1" in
+        mobj\ *) echo "A mobj field" ;;
+        sector*|line_side\ *|button\ *|anim\ *) echo "A sector or sector thinker field" ;;
+        player\ *|psprite\ *|input\ *) echo "A player field" ;;
+        hud\ *) echo "Status bar or message state" ;;
+        *rndindex) echo "prndindex or rndindex" ;;
+        *) echo "$1" ;;
+    esac
+}
+
+field() {
+    printf '### %s\n\n%s\n\n' "$1" "${2:-_No response_}"
+}
+
+fenced() {
+    local fence='```'
+    printf '### %s\n\n%s%s\n%s\n%s\n\n' "$1" "$fence" "$2" "$3" "$fence"
+}
+
+mkdir -p "$out"
+n=0
+while IFS= read -r finding; do
+    n=$((n + 1))
+    dir="$out/$n"
+    mkdir -p "$dir"
+    kind=$(jq -r .kind <<<"$finding")
+    commit=$(jq -r .commit <<<"$finding")
+    against=$(jq -r .against <<<"$finding")
+    metric=$(jq -r .metric <<<"$finding")
+    before=$(jq -r .before <<<"$finding")
+    after=$(jq -r .after <<<"$finding")
+    line=$(line_of "$commit")
+    parent_line=$(line_of "$against")
+    marker="($metric at ${commit:0:12})"
+    note=""
+    if [[ $commit == self-test-* ]]; then
+        marker="($metric at $commit)"
+        note="This finding was injected by the nightly's \`inject_regression\` input to show that filing works. Nothing regressed. Close it."
+    fi
+    rom_sha=$(git show "$commit:rom/PINNED_HASH" 2>/dev/null || cat rom/PINNED_HASH)
+    clickhouse=$(jq -r '.clickhouse // "unknown"' <<<"$line")
+
+    {
+        if [ -n "$note" ]; then
+            printf '%s\n\n' "$note"
+        fi
+        printf 'Filed by the nightly native regression walk%s.\n\n' "${run_url:+ in $run_url}"
+    } >"$dir/body.md"
+
+    if [ "$kind" = correctness ]; then
+        case "$metric" in
+            first_divergent_tic)
+                tic=${after%% *}
+                what=$(what_disagrees "$(jq -r '.first_divergent_field // ""' <<<"$line")")
+                ;;
+            *)
+                tic=$(jq -r .first_refused_tic <<<"$line")
+                what="The first refused tic, which is not a field"
+                ;;
+        esac
+        echo "native: divergence at tic $tic $marker" >"$dir/title"
+        printf 'divergence\narea: native\n' >"$dir/labels"
+        refused=$(jq -r .first_refused_tic <<<"$line")
+        repro="git checkout $commit
+make up build-clickdoom gen-probe-trace
+trace=refemu/reference_traces/demo3/probe.\$(cut -c1-12 rom/PINNED_HASH).tsv
+./target/release/clickdoom native load --fresh
+./target/release/clickdoom native diff $search_tics --probe \"\$trace\""
+        if [ "$refused" != null ] && [ "$refused" -gt 1 ]; then
+            repro="$repro
+./target/release/clickdoom native diff $((refused - 1)) --probe \"\$trace\""
+        fi
+        {
+            field "ROM sha256" "$rom_sha"
+            field "WAD sha256" "$wad_sha"
+            field "ClickHouse version" "$clickhouse"
+            field "First divergent tic (gametic)" "$tic"
+            field "First divergent frame, if a frame differs" ""
+            field "What disagrees" "$what"
+            fenced "The divergence report" text "$metric moved from $before at $against to $after at $commit.
+
+This commit's line:
+$line
+
+The line it was judged against:
+$parent_line"
+            field "Random draws at that tic" ""
+            fenced "Reproduction" shell "$repro"
+        } >>"$dir/body.md"
+    else
+        ratio=${after##*(}
+        echo "perf: $metric up ${ratio%)} on its parent $marker" >"$dir/title"
+        printf 'performance\narea: native\n' >"$dir/labels"
+        {
+            field "What kind" "A change made it slower"
+            field "Which benchmark" "The nightly native regression walk: \`scripts/native-regression-walk.sh\`, then \`clickdoom native regress\`"
+            fenced "The numbers" text "$metric: $before at $against, $after at $commit.
+Both measured in the same job on the same runner, ClickHouse $clickhouse.
+
+This commit's line:
+$line
+
+Its parent's line:
+$parent_line"
+            field "The machine, and how quiet it was" "$(jq -r '.runner_cpu // "unknown"' <<<"$line"), a GitHub-hosted runner. Parent and child ran one after the other in the same job, with nothing else in it."
+            field "What you think is happening" ""
+        } >>"$dir/body.md"
+    fi
+done <"$findings"
+echo "$n issue(s) rendered into $out"