background-agent: Scaffold week-one crash MVP pipeline

.factory/prompts/crash/link-issues.md

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+# Crash Issue Linking
+
+You are linking a crash to potentially related GitHub issues so human reviewers can quickly validate whether a fix may resolve multiple reports.
+
+## Inputs
+
+Before starting, you should have:
+
+1. **Crash report** (from `script/sentry-fetch <issue-id>` or Sentry MCP)
+2. **ANALYSIS.md** from investigation phase, including root cause and crash site
+
+If either is missing, stop and report what is missing.
+
+## Goal
+
+Search GitHub issues and produce a reviewer-ready shortlist grouped by confidence:
+
+- **High confidence**
+- **Medium confidence**
+- **Low confidence**
+
+The output is advisory only. Humans must confirm before adding closing keywords or making release claims.
+
+## Workflow
+
+### Step 1: Build Search Signals
+
+Extract concrete signals from the crash + analysis:
+
+1. Crash site function, file, and crate
+2. Error message / panic text
+3. Key stack frames (especially in-app)
+4. Reproduction trigger phrasing (user actions)
+5. Affected platform/version tags if available
+
+### Step 2: Search GitHub Issues
+
+Search **only** issues in `zed-industries/zed` (prefer `gh issue list` / `gh issue view` / GraphQL if available) by:
+
+1. Panic/error text
+2. Function/file names
+3. Crate/module names + symptom keywords
+4. Similar reproduction patterns
+
+Check both open and recently closed issues in `zed-industries/zed`.
+
+### Step 3: Score Confidence
+
+Assign confidence based on evidence quality:
+
+- **High:** direct technical overlap (same crash site or same invariant violation with matching repro language)
+- **Medium:** partial overlap (same subsystem and symptom, but indirect stack/repro match)
+- **Low:** thematic similarity only (same area/keywords without solid technical match)
+
+Avoid inflated confidence. If uncertain, downgrade.
+
+### Step 4: Produce Structured Output
+
+Write `LINKED_ISSUES.md` using this exact structure:
+
+```markdown
+# Potentially Related GitHub Issues
+
+## High Confidence
+- [#12345](https://github.com/zed-industries/zed/issues/12345) — <title>
+  - Why: <1-2 sentence evidence-backed rationale>
+  - Evidence: <stack frame / error text / repro alignment>
+
+## Medium Confidence
+- ...
+
+## Low Confidence
+- ...
+
+## Reviewer Checklist
+- [ ] Confirm High confidence issues should be referenced in PR body
+- [ ] Confirm any issue should receive closing keywords (`Fixes #...`)
+- [ ] Reject false positives before merge
+```
+
+If no credible matches are found, keep sections present and write `- None found` under each.
+
+## Rules
+
+- Do not fabricate issues or URLs.
+- Do not include issues from any repository other than `zed-industries/zed`.
+- Do not add closing keywords automatically.
+- Keep rationale short and evidence-based.
+- Favor precision over recall.

.github/workflows/background_agent_mvp.yml

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+name: background_agent_mvp
+
+on:
+  schedule:
+    - cron: "0 16 * * 1-5"
+  workflow_dispatch:
+    inputs:
+      crash_ids:
+        description: "Optional comma-separated Sentry issue IDs (e.g. ZED-4VS,ZED-123)"
+        required: false
+        type: string
+      reviewers:
+        description: "Optional comma-separated GitHub reviewer handles"
+        required: false
+        type: string
+      top:
+        description: "Top N candidates when crash_ids is empty"
+        required: false
+        type: string
+        default: "3"
+
+permissions:
+  contents: write
+  pull-requests: write
+
+env:
+  FACTORY_API_KEY: ${{ secrets.FACTORY_API_KEY }}
+  DROID_MODEL: claude-opus-4-5-20251101
+  SENTRY_ORG: zed-dev
+
+jobs:
+  run-mvp:
+    runs-on: ubuntu-latest
+    timeout-minutes: 180
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Install Droid CLI
+        run: |
+          curl -fsSL https://app.factory.ai/cli | sh
+          echo "${HOME}/.local/bin" >> "$GITHUB_PATH"
+          echo "DROID_BIN=${HOME}/.local/bin/droid" >> "$GITHUB_ENV"
+          "${HOME}/.local/bin/droid" --version
+
+      - name: Setup Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Resolve reviewers
+        id: reviewers
+        env:
+          INPUT_REVIEWERS: ${{ inputs.reviewers }}
+          DEFAULT_REVIEWERS: ${{ vars.BACKGROUND_AGENT_REVIEWERS }}
+        run: |
+          set -euo pipefail
+          if [ -z "$DEFAULT_REVIEWERS" ]; then
+            DEFAULT_REVIEWERS="eholk,morgankrey,osiewicz,bennetbo"
+          fi
+          REVIEWERS="${INPUT_REVIEWERS:-$DEFAULT_REVIEWERS}"
+          REVIEWERS="$(echo "$REVIEWERS" | tr -d '[:space:]')"
+          echo "reviewers=$REVIEWERS" >> "$GITHUB_OUTPUT"
+
+      - name: Select crash candidates
+        id: candidates
+        env:
+          INPUT_CRASH_IDS: ${{ inputs.crash_ids }}
+          INPUT_TOP: ${{ inputs.top }}
+          SENTRY_AUTH_TOKEN: ${{ secrets.SENTRY_BACKGROUND_AGENT_MVP_TOKEN }}
+        run: |
+          set -euo pipefail
+
+          PREFETCH_DIR="/tmp/crash-data"
+          ARGS=(--select-only --prefetch-dir "$PREFETCH_DIR" --org "$SENTRY_ORG")
+          if [ -n "$INPUT_CRASH_IDS" ]; then
+            ARGS+=(--crash-ids "$INPUT_CRASH_IDS")
+          else
+            TARGET_DRAFT_PRS="${INPUT_TOP:-3}"
+            if ! [[ "$TARGET_DRAFT_PRS" =~ ^[0-9]+$ ]] || [ "$TARGET_DRAFT_PRS" -lt 1 ]; then
+              TARGET_DRAFT_PRS="3"
+            fi
+            CANDIDATE_TOP=$((TARGET_DRAFT_PRS * 5))
+            if [ "$CANDIDATE_TOP" -gt 100 ]; then
+              CANDIDATE_TOP=100
+            fi
+            ARGS+=(--top "$CANDIDATE_TOP" --sample-size 100)
+          fi
+
+          IDS="$(python3 script/run-background-agent-mvp-local "${ARGS[@]}")"
+
+          if [ -z "$IDS" ]; then
+            echo "No candidates selected"
+            exit 1
+          fi
+
+          echo "Using crash IDs: $IDS"
+          echo "ids=$IDS" >> "$GITHUB_OUTPUT"
+
+      - name: Run background agent pipeline per crash
+        id: pipeline
+        env:
+          GH_TOKEN: ${{ github.token }}
+          REVIEWERS: ${{ steps.reviewers.outputs.reviewers }}
+          CRASH_IDS: ${{ steps.candidates.outputs.ids }}
+          TARGET_DRAFT_PRS_INPUT: ${{ inputs.top }}
+        run: |
+          set -euo pipefail
+
+          git config user.name "factory-droid[bot]"
+          git config user.email "138933559+factory-droid[bot]@users.noreply.github.com"
+
+          # Crash ID format validation regex
+          CRASH_ID_PATTERN='^[A-Za-z0-9]+-[A-Za-z0-9]+$'
+          TARGET_DRAFT_PRS="${TARGET_DRAFT_PRS_INPUT:-3}"
+          if ! [[ "$TARGET_DRAFT_PRS" =~ ^[0-9]+$ ]] || [ "$TARGET_DRAFT_PRS" -lt 1 ]; then
+            TARGET_DRAFT_PRS="3"
+          fi
+          CREATED_DRAFT_PRS=0
+
+          IFS=',' read -r -a CRASH_ID_ARRAY <<< "$CRASH_IDS"
+
+          for CRASH_ID in "${CRASH_ID_ARRAY[@]}"; do
+            if [ "$CREATED_DRAFT_PRS" -ge "$TARGET_DRAFT_PRS" ]; then
+              echo "Reached target draft PR count ($TARGET_DRAFT_PRS), stopping candidate processing"
+              break
+            fi
+
+            CRASH_ID="$(echo "$CRASH_ID" | xargs)"
+            [ -z "$CRASH_ID" ] && continue
+
+            # Validate crash ID format to prevent injection via branch names or prompts
+            if ! [[ "$CRASH_ID" =~ $CRASH_ID_PATTERN ]]; then
+              echo "ERROR: Invalid crash ID format: '$CRASH_ID' — skipping"
+              continue
+            fi
+
+            BRANCH="background-agent/mvp-${CRASH_ID,,}-$(date +%Y%m%d)"
+            echo "Running crash pipeline for $CRASH_ID on $BRANCH"
+
+            # Deduplication: skip if a draft PR already exists for this crash
+            EXISTING_BRANCH_PR="$(gh pr list --head "$BRANCH" --state open --json number --jq '.[0].number' || echo "")"
+            if [ -n "$EXISTING_BRANCH_PR" ]; then
+              echo "Draft PR #$EXISTING_BRANCH_PR already exists for $CRASH_ID — skipping"
+              continue
+            fi
+
+            git fetch origin main
+            git checkout -B "$BRANCH" origin/main
+
+            CRASH_DATA_FILE="/tmp/crash-data/crash-${CRASH_ID}.md"
+            if [ ! -f "$CRASH_DATA_FILE" ]; then
+              echo "WARNING: No pre-fetched crash data for $CRASH_ID at $CRASH_DATA_FILE — skipping"
+              continue
+            fi
+
+            python3 -c "
+          import sys
+          crash_id, data_file = sys.argv[1], sys.argv[2]
+          prompt = f'''You are running the weekly background crash-fix MVP pipeline for crash {crash_id}.
+
+          The crash report has been pre-fetched and is available at: {data_file}
+          Read this file to get the crash data. Do not call script/sentry-fetch.
+
+          Required workflow:
+          1. Read the crash report from {data_file}
+          2. Follow .factory/prompts/crash/investigate.md and write ANALYSIS.md
+          3. Follow .factory/prompts/crash/link-issues.md and write LINKED_ISSUES.md
+          4. Follow .factory/prompts/crash/fix.md to implement a minimal fix with tests
+          5. Run validators required by the fix prompt for the affected crate(s)
+          6. Write PR_BODY.md with sections:
+             - Crash Summary
+             - Root Cause
+             - Fix
+             - Validation
+             - Potentially Related Issues (High/Medium/Low from LINKED_ISSUES.md)
+             - Reviewer Checklist
+
+          Constraints:
+          - Do not merge or auto-approve.
+          - Keep changes narrowly scoped to this crash.
+          - Do not modify files in .github/, .factory/, or script/ directories.
+          - When investigating git history, limit your search to the last 2 weeks of commits. Do not traverse older history.
+          - If the crash is not solvable with available context, write a clear blocker summary to PR_BODY.md.
+          '''
+          import textwrap
+          with open('/tmp/background-agent-prompt.md', 'w') as f:
+              f.write(textwrap.dedent(prompt))
+          " "$CRASH_ID" "$CRASH_DATA_FILE"
+
+            if ! "$DROID_BIN" exec --auto medium -m "$DROID_MODEL" -f /tmp/background-agent-prompt.md; then
+              echo "Droid execution failed for $CRASH_ID, continuing to next candidate"
+              continue
+            fi
+
+            for REPORT_FILE in ANALYSIS.md LINKED_ISSUES.md PR_BODY.md; do
+              if [ -f "$REPORT_FILE" ]; then
+                echo "::group::${CRASH_ID} ${REPORT_FILE}"
+                cat "$REPORT_FILE"
+                echo "::endgroup::"
+              fi
+            done
+
+            if git diff --quiet; then
+              echo "No code changes produced for $CRASH_ID"
+              continue
+            fi
+
+            # Stage only expected file types — not git add -A
+            git add -- '*.rs' '*.toml' 'Cargo.lock' 'ANALYSIS.md' 'LINKED_ISSUES.md' 'PR_BODY.md'
+
+            # Reject changes to protected paths
+            PROTECTED_CHANGES="$(git diff --cached --name-only | grep -E '^(\.github/|\.factory/|script/)' || true)"
+            if [ -n "$PROTECTED_CHANGES" ]; then
+              echo "ERROR: Agent modified protected paths — aborting commit for $CRASH_ID:"
+              echo "$PROTECTED_CHANGES"
+              git reset HEAD -- .
+              continue
+            fi
+
+            if ! git diff --cached --quiet; then
+              git commit -m "fix: draft crash fix for ${CRASH_ID}"
+            fi
+
+            git push -u origin "$BRANCH"
+
+            TITLE="fix: draft crash fix for ${CRASH_ID}"
+            BODY_FILE="PR_BODY.md"
+            if [ ! -f "$BODY_FILE" ]; then
+              BODY_FILE="/tmp/pr-body-${CRASH_ID}.md"
+              printf "Automated draft crash-fix pipeline output for %s.\n\nNo PR_BODY.md was generated by the agent; please review commit and linked artifacts manually.\n" "$CRASH_ID" > "$BODY_FILE"
+            fi
+
+            EXISTING_PR="$(gh pr list --head "$BRANCH" --json number --jq '.[0].number')"
+            if [ -n "$EXISTING_PR" ]; then
+              gh pr edit "$EXISTING_PR" --title "$TITLE" --body-file "$BODY_FILE"
+              PR_NUMBER="$EXISTING_PR"
+            else
+              PR_URL="$(gh pr create --draft --base main --head "$BRANCH" --title "$TITLE" --body-file "$BODY_FILE")"
+              PR_NUMBER="$(basename "$PR_URL")"
+            fi
+
+            if [ -n "$REVIEWERS" ]; then
+              IFS=',' read -r -a REVIEWER_ARRAY <<< "$REVIEWERS"
+              for REVIEWER in "${REVIEWER_ARRAY[@]}"; do
+                [ -z "$REVIEWER" ] && continue
+                gh pr edit "$PR_NUMBER" --add-reviewer "$REVIEWER" || true
+              done
+            fi
+
+            CREATED_DRAFT_PRS=$((CREATED_DRAFT_PRS + 1))
+            echo "Created/updated draft PRs this run: $CREATED_DRAFT_PRS/$TARGET_DRAFT_PRS"
+          done
+
+          echo "created_draft_prs=$CREATED_DRAFT_PRS" >> "$GITHUB_OUTPUT"
+          echo "target_draft_prs=$TARGET_DRAFT_PRS" >> "$GITHUB_OUTPUT"
+
+      - name: Cleanup pre-fetched crash data
+        if: always()
+        run: rm -rf /tmp/crash-data
+
+      - name: Workflow summary
+        if: always()
+        env:
+          SUMMARY_CRASH_IDS: ${{ steps.candidates.outputs.ids }}
+          SUMMARY_REVIEWERS: ${{ steps.reviewers.outputs.reviewers }}
+          SUMMARY_CREATED_DRAFT_PRS: ${{ steps.pipeline.outputs.created_draft_prs }}
+          SUMMARY_TARGET_DRAFT_PRS: ${{ steps.pipeline.outputs.target_draft_prs }}
+        run: |
+          {
+            echo "## Background Agent MVP"
+            echo ""
+            echo "- Crash IDs: ${SUMMARY_CRASH_IDS:-none}"
+            echo "- Reviewer routing: ${SUMMARY_REVIEWERS:-NOT CONFIGURED}"
+            echo "- Draft PRs created: ${SUMMARY_CREATED_DRAFT_PRS:-0}/${SUMMARY_TARGET_DRAFT_PRS:-3}"
+            echo "- Pipeline: investigate -> link-issues -> fix -> draft PR"
+          } >> "$GITHUB_STEP_SUMMARY"
+
+concurrency:
+  group: background-agent-mvp
+  cancel-in-progress: false