diff --git a/.github/actions/agent-status-comment/action.yml b/.github/actions/agent-status-comment/action.yml
new file mode 100644
index 0000000000..70bea09867
--- /dev/null
+++ b/.github/actions/agent-status-comment/action.yml
@@ -0,0 +1,126 @@
+name: Agent Status Comment
+description: >-
+  Post or update a status comment on an issue or PR for a fullsend agent
+  workflow run. Start comments include a run-specific HTML marker. On
+  completion, the start comment is edited in place if it is still the
+  last comment; otherwise a new completion comment is posted. Cancelled
+  runs delete their start comment to avoid stale "in progress" messages.
+
+inputs:
+  description:
+    description: >-
+      Human-readable action phrase (e.g. "Reviewing this PR"). Used as-is for
+      start comments; completion comments prepend "Finished". Must be a
+      hardcoded literal — do not pass user-controlled content.
+    required: true
+  number:
+    description: Issue or PR number to comment on
+    required: true
+  repo:
+    description: Repository full name (owner/repo) to comment on
+    required: true
+  sha:
+    description: Commit SHA the workflow is running against
+    required: true
+  token:
+    description: GitHub token with issues:write permission
+    required: true
+  status:
+    description: >-
+      Workflow job status (success/failure/cancelled). When set, updates or
+      posts a completion comment; when empty, posts a start comment.
+    required: false
+    default: ''
+
+runs:
+  using: composite
+  steps:
+    - name: Post status comment
+      shell: bash
+      env:
+        GH_TOKEN: ${{ inputs.token }}
+        DESCRIPTION: ${{ inputs.description }}
+        NUMBER: ${{ inputs.number }}
+        REPO: ${{ inputs.repo }}
+        SHA: ${{ inputs.sha }}
+        STATUS: ${{ inputs.status }}
+      run: |
+        set -euo pipefail
+
+        if [[ -z "${NUMBER}" || "${NUMBER}" == "null" ]]; then
+          echo "::notice::No issue/PR number — skipping status comment"
+          exit 0
+        fi
+
+        MARKER="<!-- fullsend:agent-status:${GITHUB_RUN_ID} -->"
+        RUN_URL="${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}/actions/runs/${GITHUB_RUN_ID}"
+        SHORT_SHA="${SHA:0:7}"
+        TIMESTAMP=$(date -u +'%-I:%M %p UTC')
+
+        find_start_comment() {
+          gh api "repos/${REPO}/issues/${NUMBER}/comments" \
+            --paginate \
+            --jq "[.[] | select(.body | contains(\"${MARKER}\")) | .id] | first" \
+            2>/dev/null || true
+        }
+
+        if [[ -z "${STATUS}" ]]; then
+          # Post start comment
+          printf -v BODY '%s\n%s\n%s' \
+            "${MARKER}" \
+            "🤖 ${DESCRIPTION} · Started ${TIMESTAMP}" \
+            "Commit: \`${SHORT_SHA}\` · [View workflow run →](${RUN_URL})"
+          gh issue comment "${NUMBER}" --repo "${REPO}" --body "${BODY}"
+
+        elif [[ "${STATUS}" == "cancelled" ]]; then
+          # Cancelled (superseded) run — delete the start comment.
+          COMMENT_ID=$(find_start_comment)
+          if [[ -n "${COMMENT_ID}" && "${COMMENT_ID}" != "null" ]]; then
+            gh api -X DELETE "repos/${REPO}/issues/comments/${COMMENT_ID}" 2>/dev/null || true
+          fi
+
+        else
+          # Completion — edit in place if start comment is still last,
+          # otherwise post a new comment.
+          case "${STATUS}" in
+            success)   STATUS_LABEL="✅ Success" ;;
+            failure)   STATUS_LABEL="❌ Failure" ;;
+            *)         STATUS_LABEL="❓ ${STATUS}" ;;
+          esac
+
+          COMMENT_ID=$(find_start_comment)
+
+          # Extract start time from the existing comment body
+          START_TIME=""
+          if [[ -n "${COMMENT_ID}" && "${COMMENT_ID}" != "null" ]]; then
+            START_TIME=$(gh api "repos/${REPO}/issues/comments/${COMMENT_ID}" \
+              --jq '.body' 2>/dev/null \
+              | grep -oP 'Started \K[0-9]+:[0-9]+ [AP]M UTC' || true)
+          fi
+
+          if [[ -n "${START_TIME}" ]]; then
+            TIME_PART=" · Started ${START_TIME} · Completed ${TIMESTAMP}"
+          else
+            TIME_PART=" · Completed ${TIMESTAMP}"
+          fi
+
+          printf -v BODY '%s\n%s\n%s' \
+            "${MARKER}" \
+            "🤖 Finished ${DESCRIPTION} · ${STATUS_LABEL}${TIME_PART}" \
+            "Commit: \`${SHORT_SHA}\` · [View workflow run →](${RUN_URL})"
+
+          if [[ -n "${COMMENT_ID}" && "${COMMENT_ID}" != "null" ]]; then
+            # Check if start comment is the last comment on the issue/PR
+            LAST_COMMENT_ID=$(gh api "repos/${REPO}/issues/${NUMBER}/comments?per_page=1&direction=desc" \
+              --jq '.[0].id' 2>/dev/null || true)
+            if [[ "${COMMENT_ID}" == "${LAST_COMMENT_ID}" ]]; then
+              gh api -X PATCH "repos/${REPO}/issues/comments/${COMMENT_ID}" \
+                -f body="${BODY}" 2>/dev/null || true
+            else
+              gh issue comment "${NUMBER}" --repo "${REPO}" --body "${BODY}"
+            fi
+          else
+            # Start comment not found — post fresh
+            gh issue comment "${NUMBER}" --repo "${REPO}" --body "${BODY}"
+          fi
+        fi
diff --git a/.github/workflows/reusable-code.yml b/.github/workflows/reusable-code.yml
index 722b937691..ef66c32de7 100644
--- a/.github/workflows/reusable-code.yml
+++ b/.github/workflows/reusable-code.yml
@@ -118,6 +118,10 @@ jobs:
           fetch-depth: 0
           persist-credentials: false
 
+      - name: Record target commit SHA
+        id: target-sha
+        run: echo "sha=$(git -C target-repo rev-parse HEAD)" >> "$GITHUB_OUTPUT"
+
       - name: Validate inputs
         env:
           ISSUE_NUMBER: ${{ fromJSON(inputs.event_payload).issue.number }}
@@ -142,6 +146,17 @@ jobs:
           CODE_ISSUE_NUMBER: ${{ fromJSON(inputs.event_payload).issue.number }}
         run: bash .github/scripts/setup-agent-env.sh
 
+      - name: Post start comment
+        if: steps.app-token.outputs.token != ''
+        continue-on-error: true
+        uses: fullsend-ai/fullsend/.github/actions/agent-status-comment@v0
+        with:
+          description: Implementing changes and creating a PR
+          number: ${{ fromJSON(inputs.event_payload).issue.number }}
+          repo: ${{ inputs.source_repo }}
+          sha: ${{ steps.target-sha.outputs.sha }}
+          token: ${{ steps.app-token.outputs.token }}
+
       - name: Run code agent
         uses: fullsend-ai/fullsend@v0
         env:
@@ -154,3 +169,15 @@ jobs:
         with:
           agent: code
           version: ${{ inputs.fullsend_version }}
+
+      - name: Post completion comment
+        if: always() && steps.app-token.outputs.token != ''
+        continue-on-error: true
+        uses: fullsend-ai/fullsend/.github/actions/agent-status-comment@v0
+        with:
+          description: Implementing changes and creating a PR
+          number: ${{ fromJSON(inputs.event_payload).issue.number }}
+          repo: ${{ inputs.source_repo }}
+          sha: ${{ steps.target-sha.outputs.sha }}
+          token: ${{ steps.app-token.outputs.token }}
+          status: ${{ job.status }}
diff --git a/.github/workflows/reusable-fix.yml b/.github/workflows/reusable-fix.yml
index 018087927b..b4a68bb8be 100644
--- a/.github/workflows/reusable-fix.yml
+++ b/.github/workflows/reusable-fix.yml
@@ -340,6 +340,17 @@ jobs:
           FIX_REPO_FULL_NAME: ${{ inputs.source_repo }}
         run: bash .github/scripts/setup-agent-env.sh
 
+      - name: Post start comment
+        if: steps.app-token.outputs.token != ''
+        continue-on-error: true
+        uses: fullsend-ai/fullsend/.github/actions/agent-status-comment@v0
+        with:
+          description: Addressing review feedback on this PR
+          number: ${{ steps.context.outputs.pr_number }}
+          repo: ${{ inputs.source_repo }}
+          sha: ${{ steps.pre-agent.outputs.head }}
+          token: ${{ steps.app-token.outputs.token }}
+
       - name: Run fix agent
         uses: fullsend-ai/fullsend@v0
         env:
@@ -356,3 +367,15 @@ jobs:
         with:
           agent: fix
           version: ${{ inputs.fullsend_version }}
+
+      - name: Post completion comment
+        if: always() && steps.app-token.outputs.token != ''
+        continue-on-error: true
+        uses: fullsend-ai/fullsend/.github/actions/agent-status-comment@v0
+        with:
+          description: Addressing review feedback on this PR
+          number: ${{ steps.context.outputs.pr_number }}
+          repo: ${{ inputs.source_repo }}
+          sha: ${{ steps.pre-agent.outputs.head }}
+          token: ${{ steps.app-token.outputs.token }}
+          status: ${{ job.status }}
diff --git a/.github/workflows/reusable-retro.yml b/.github/workflows/reusable-retro.yml
index 747fac7c04..9c15ff6256 100644
--- a/.github/workflows/reusable-retro.yml
+++ b/.github/workflows/reusable-retro.yml
@@ -116,6 +116,10 @@ jobs:
           fetch-depth: 1
           persist-credentials: false
 
+      - name: Record target commit SHA
+        id: target-sha
+        run: echo "sha=$(git -C target-repo rev-parse HEAD)" >> "$GITHUB_OUTPUT"
+
       - name: Setup GCP and prepare credentials
         uses: fullsend-ai/fullsend/.github/actions/setup-gcp@v0
         with:
@@ -131,6 +135,17 @@ jobs:
           RETRO_CLOUD_ML_REGION: ${{ inputs.gcp_region }}
         run: bash .github/scripts/setup-agent-env.sh
 
+      - name: Post start comment
+        if: steps.app-token.outputs.token != ''
+        continue-on-error: true
+        uses: fullsend-ai/fullsend/.github/actions/agent-status-comment@v0
+        with:
+          description: Running a retrospective
+          number: ${{ fromJSON(inputs.event_payload).pull_request.number || fromJSON(inputs.event_payload).issue.number }}
+          repo: ${{ inputs.source_repo }}
+          sha: ${{ steps.target-sha.outputs.sha }}
+          token: ${{ steps.app-token.outputs.token }}
+
       - name: Run retro agent
         uses: fullsend-ai/fullsend@v0
         env:
@@ -142,3 +157,15 @@ jobs:
         with:
           agent: retro
           version: ${{ inputs.fullsend_version }}
+
+      - name: Post completion comment
+        if: always() && steps.app-token.outputs.token != ''
+        continue-on-error: true
+        uses: fullsend-ai/fullsend/.github/actions/agent-status-comment@v0
+        with:
+          description: Running a retrospective
+          number: ${{ fromJSON(inputs.event_payload).pull_request.number || fromJSON(inputs.event_payload).issue.number }}
+          repo: ${{ inputs.source_repo }}
+          sha: ${{ steps.target-sha.outputs.sha }}
+          token: ${{ steps.app-token.outputs.token }}
+          status: ${{ job.status }}
diff --git a/.github/workflows/reusable-review.yml b/.github/workflows/reusable-review.yml
index e0e4337348..e583a976c4 100644
--- a/.github/workflows/reusable-review.yml
+++ b/.github/workflows/reusable-review.yml
@@ -117,6 +117,10 @@ jobs:
           fetch-depth: 1
           persist-credentials: false
 
+      - name: Record target commit SHA
+        id: target-sha
+        run: echo "sha=$(git -C target-repo rev-parse HEAD)" >> "$GITHUB_OUTPUT"
+
       - name: Pre-fetch prior review context
         id: prior-review
         env:
@@ -144,6 +148,17 @@ jobs:
           REVIEW_CLOUD_ML_REGION: ${{ inputs.gcp_region }}
         run: bash .github/scripts/setup-agent-env.sh
 
+      - name: Post start comment
+        if: steps.app-token.outputs.token != ''
+        continue-on-error: true
+        uses: fullsend-ai/fullsend/.github/actions/agent-status-comment@v0
+        with:
+          description: Reviewing this PR
+          number: ${{ fromJSON(inputs.event_payload).pull_request.number || fromJSON(inputs.event_payload).issue.number }}
+          repo: ${{ inputs.source_repo }}
+          sha: ${{ steps.target-sha.outputs.sha }}
+          token: ${{ steps.app-token.outputs.token }}
+
       - name: Run review agent
         uses: fullsend-ai/fullsend@v0
         env:
@@ -158,3 +173,15 @@ jobs:
         with:
           agent: review
           version: ${{ inputs.fullsend_version }}
+
+      - name: Post completion comment
+        if: always() && steps.app-token.outputs.token != ''
+        continue-on-error: true
+        uses: fullsend-ai/fullsend/.github/actions/agent-status-comment@v0
+        with:
+          description: Reviewing this PR
+          number: ${{ fromJSON(inputs.event_payload).pull_request.number || fromJSON(inputs.event_payload).issue.number }}
+          repo: ${{ inputs.source_repo }}
+          sha: ${{ steps.target-sha.outputs.sha }}
+          token: ${{ steps.app-token.outputs.token }}
+          status: ${{ job.status }}
diff --git a/.github/workflows/reusable-triage.yml b/.github/workflows/reusable-triage.yml
index fbf0a0f3cd..f93d0c1c25 100644
--- a/.github/workflows/reusable-triage.yml
+++ b/.github/workflows/reusable-triage.yml
@@ -116,6 +116,10 @@ jobs:
           fetch-depth: 1
           persist-credentials: false
 
+      - name: Record target commit SHA
+        id: target-sha
+        run: echo "sha=$(git -C target-repo rev-parse HEAD)" >> "$GITHUB_OUTPUT"
+
       - name: Setup GCP and prepare credentials
         uses: fullsend-ai/fullsend/.github/actions/setup-gcp@v0
         with:
@@ -131,6 +135,17 @@ jobs:
           TRIAGE_CLOUD_ML_REGION: ${{ inputs.gcp_region }}
         run: bash .github/scripts/setup-agent-env.sh
 
+      - name: Post start comment
+        if: steps.app-token.outputs.token != ''
+        continue-on-error: true
+        uses: fullsend-ai/fullsend/.github/actions/agent-status-comment@v0
+        with:
+          description: Triaging this issue
+          number: ${{ fromJSON(inputs.event_payload).issue.number }}
+          repo: ${{ inputs.source_repo }}
+          sha: ${{ steps.target-sha.outputs.sha }}
+          token: ${{ steps.app-token.outputs.token }}
+
       - name: Run triage agent
         uses: fullsend-ai/fullsend@v0
         env:
@@ -138,3 +153,15 @@ jobs:
         with:
           agent: triage
           version: ${{ inputs.fullsend_version }}
+
+      - name: Post completion comment
+        if: always() && steps.app-token.outputs.token != ''
+        continue-on-error: true
+        uses: fullsend-ai/fullsend/.github/actions/agent-status-comment@v0
+        with:
+          description: Triaging this issue
+          number: ${{ fromJSON(inputs.event_payload).issue.number }}
+          repo: ${{ inputs.source_repo }}
+          sha: ${{ steps.target-sha.outputs.sha }}
+          token: ${{ steps.app-token.outputs.token }}
+          status: ${{ job.status }}
diff --git a/internal/scaffold/fullsend-repo/.github/actions/agent-status-comment/action.yml b/internal/scaffold/fullsend-repo/.github/actions/agent-status-comment/action.yml
new file mode 100644
index 0000000000..70bea09867
--- /dev/null
+++ b/internal/scaffold/fullsend-repo/.github/actions/agent-status-comment/action.yml
@@ -0,0 +1,126 @@
+name: Agent Status Comment
+description: >-
+  Post or update a status comment on an issue or PR for a fullsend agent
+  workflow run. Start comments include a run-specific HTML marker. On
+  completion, the start comment is edited in place if it is still the
+  last comment; otherwise a new completion comment is posted. Cancelled
+  runs delete their start comment to avoid stale "in progress" messages.
+
+inputs:
+  description:
+    description: >-
+      Human-readable action phrase (e.g. "Reviewing this PR"). Used as-is for
+      start comments; completion comments prepend "Finished". Must be a
+      hardcoded literal — do not pass user-controlled content.
+    required: true
+  number:
+    description: Issue or PR number to comment on
+    required: true
+  repo:
+    description: Repository full name (owner/repo) to comment on
+    required: true
+  sha:
+    description: Commit SHA the workflow is running against
+    required: true
+  token:
+    description: GitHub token with issues:write permission
+    required: true
+  status:
+    description: >-
+      Workflow job status (success/failure/cancelled). When set, updates or
+      posts a completion comment; when empty, posts a start comment.
+    required: false
+    default: ''
+
+runs:
+  using: composite
+  steps:
+    - name: Post status comment
+      shell: bash
+      env:
+        GH_TOKEN: ${{ inputs.token }}
+        DESCRIPTION: ${{ inputs.description }}
+        NUMBER: ${{ inputs.number }}
+        REPO: ${{ inputs.repo }}
+        SHA: ${{ inputs.sha }}
+        STATUS: ${{ inputs.status }}
+      run: |
+        set -euo pipefail
+
+        if [[ -z "${NUMBER}" || "${NUMBER}" == "null" ]]; then
+          echo "::notice::No issue/PR number — skipping status comment"
+          exit 0
+        fi
+
+        MARKER="<!-- fullsend:agent-status:${GITHUB_RUN_ID} -->"
+        RUN_URL="${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}/actions/runs/${GITHUB_RUN_ID}"
+        SHORT_SHA="${SHA:0:7}"
+        TIMESTAMP=$(date -u +'%-I:%M %p UTC')
+
+        find_start_comment() {
+          gh api "repos/${REPO}/issues/${NUMBER}/comments" \
+            --paginate \
+            --jq "[.[] | select(.body | contains(\"${MARKER}\")) | .id] | first" \
+            2>/dev/null || true
+        }
+
+        if [[ -z "${STATUS}" ]]; then
+          # Post start comment
+          printf -v BODY '%s\n%s\n%s' \
+            "${MARKER}" \
+            "🤖 ${DESCRIPTION} · Started ${TIMESTAMP}" \
+            "Commit: \`${SHORT_SHA}\` · [View workflow run →](${RUN_URL})"
+          gh issue comment "${NUMBER}" --repo "${REPO}" --body "${BODY}"
+
+        elif [[ "${STATUS}" == "cancelled" ]]; then
+          # Cancelled (superseded) run — delete the start comment.
+          COMMENT_ID=$(find_start_comment)
+          if [[ -n "${COMMENT_ID}" && "${COMMENT_ID}" != "null" ]]; then
+            gh api -X DELETE "repos/${REPO}/issues/comments/${COMMENT_ID}" 2>/dev/null || true
+          fi
+
+        else
+          # Completion — edit in place if start comment is still last,
+          # otherwise post a new comment.
+          case "${STATUS}" in
+            success)   STATUS_LABEL="✅ Success" ;;
+            failure)   STATUS_LABEL="❌ Failure" ;;
+            *)         STATUS_LABEL="❓ ${STATUS}" ;;
+          esac
+
+          COMMENT_ID=$(find_start_comment)
+
+          # Extract start time from the existing comment body
+          START_TIME=""
+          if [[ -n "${COMMENT_ID}" && "${COMMENT_ID}" != "null" ]]; then
+            START_TIME=$(gh api "repos/${REPO}/issues/comments/${COMMENT_ID}" \
+              --jq '.body' 2>/dev/null \
+              | grep -oP 'Started \K[0-9]+:[0-9]+ [AP]M UTC' || true)
+          fi
+
+          if [[ -n "${START_TIME}" ]]; then
+            TIME_PART=" · Started ${START_TIME} · Completed ${TIMESTAMP}"
+          else
+            TIME_PART=" · Completed ${TIMESTAMP}"
+          fi
+
+          printf -v BODY '%s\n%s\n%s' \
+            "${MARKER}" \
+            "🤖 Finished ${DESCRIPTION} · ${STATUS_LABEL}${TIME_PART}" \
+            "Commit: \`${SHORT_SHA}\` · [View workflow run →](${RUN_URL})"
+
+          if [[ -n "${COMMENT_ID}" && "${COMMENT_ID}" != "null" ]]; then
+            # Check if start comment is the last comment on the issue/PR
+            LAST_COMMENT_ID=$(gh api "repos/${REPO}/issues/${NUMBER}/comments?per_page=1&direction=desc" \
+              --jq '.[0].id' 2>/dev/null || true)
+            if [[ "${COMMENT_ID}" == "${LAST_COMMENT_ID}" ]]; then
+              gh api -X PATCH "repos/${REPO}/issues/comments/${COMMENT_ID}" \
+                -f body="${BODY}" 2>/dev/null || true
+            else
+              gh issue comment "${NUMBER}" --repo "${REPO}" --body "${BODY}"
+            fi
+          else
+            # Start comment not found — post fresh
+            gh issue comment "${NUMBER}" --repo "${REPO}" --body "${BODY}"
+          fi
+        fi