diff --git a/.github/sts/slack-config.sts.yaml b/.github/sts/slack-config.sts.yaml
index c67fe67..f93f42b 100644
--- a/.github/sts/slack-config.sts.yaml
+++ b/.github/sts/slack-config.sts.yaml
@@ -13,5 +13,8 @@ subject:
   - repo:tempoxyz@211589300/tip.bot@1232143975:environment:preview
   - repo:tempoxyz@211589300/tip.bot@1232143975:environment:production
 
+claim_pattern:
+  job_workflow_ref: tempoxyz/tip\.bot/\.github/workflows/(preview_deploy|preview_destroy|preview_sweep|production)\.yml@refs/heads/main
+
 permissions:
   secrets: write
diff --git a/.github/sts/workflow-member.sts.yaml b/.github/sts/workflow-member.sts.yaml
new file mode 100644
index 0000000..7f13839
--- /dev/null
+++ b/.github/sts/workflow-member.sts.yaml
@@ -0,0 +1,12 @@
+# Allows secret-bearing workflows loaded from main to check whether the actor
+# who ultimately triggered the run is a current tempoxyz organization member.
+# The token grants only organization membership visibility.
+subject:
+  - repo:tempoxyz@211589300/tip.bot@1232143975:pull_request
+  - repo:tempoxyz@211589300/tip.bot@1232143975:ref:refs/heads/main
+
+claim_pattern:
+  job_workflow_ref: tempoxyz/tip\.bot/\.github/workflows/(preview|preview_destroy|preview_sweep|production)\.yml@refs/heads/main
+
+permissions:
+  members: read
diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
index 8bddef6..1cbbad2 100644
--- a/.github/workflows/check.yml
+++ b/.github/workflows/check.yml
@@ -7,12 +7,6 @@ on:
         default: false
         required: false
         type: boolean
-  workflow_dispatch:
-    inputs:
-      skip_workers:
-        default: false
-        required: false
-        type: boolean
 
 permissions:
   contents: read
diff --git a/.github/workflows/preview.yml b/.github/workflows/preview.yml
new file mode 100644
index 0000000..b230280
--- /dev/null
+++ b/.github/workflows/preview.yml
@@ -0,0 +1,69 @@
+name: Preview
+
+on: # zizmor: ignore[dangerous-triggers] Loads from main and authorizes the triggering actor before checking out PR code.
+  workflow_run:
+    workflows: [Pull Request]
+    types: [completed]
+
+permissions: {}
+
+jobs:
+  authorize:
+    name: Authorize
+    if: github.event.workflow_run.conclusion == 'success'
+    runs-on: ubuntu-latest
+    outputs:
+      pr_number: ${{ steps.pr.outputs.number }}
+    permissions:
+      contents: read
+      id-token: write
+      pull-requests: read
+    steps:
+      - name: Mint organization membership token
+        id: member_token
+        uses: tempoxyz/gh-actions/actions/github-sts@dd1014bf8244fded7a501e701cafab240a4f9f0e # main
+        with:
+          policy: workflow-member
+
+      - name: Check triggering actor organization membership
+        env:
+          ACTOR: ${{ github.run_attempt != '1' && github.triggering_actor || github.event.workflow_run.triggering_actor.login }}
+          GH_TOKEN: ${{ steps.member_token.outputs.token }}
+        run: gh api --silent "orgs/tempoxyz/members/${ACTOR}"
+
+      - name: Resolve pull request
+        id: pr
+        env:
+          GH_TOKEN: ${{ github.token }}
+          HEAD_SHA: ${{ github.event.workflow_run.head_sha }}
+        run: |
+          NUMBER=$(gh api "repos/${{ github.repository }}/commits/${HEAD_SHA}/pulls" \
+            --jq 'map(select(.state == "open" and .draft == false)) | first | .number // empty')
+          if [ -z "$NUMBER" ]; then
+            echo "No open, ready pull request found for ${HEAD_SHA}."
+            exit 1
+          fi
+          echo "number=$NUMBER" >> "$GITHUB_OUTPUT"
+
+  preview:
+    name: Preview
+    needs: authorize
+    permissions:
+      contents: read
+      id-token: write
+      issues: write
+      pull-requests: write
+    uses: ./.github/workflows/preview_deploy.yml
+    with:
+      pr_number: ${{ needs.authorize.outputs.pr_number }}
+      sha: ${{ github.event.workflow_run.head_sha }}
+      twitter_bot_handle: ${{ vars.TWITTER_BOT_HANDLE || 'tipbotgg' }}
+    secrets:
+      CLOUDFLARE_ACCOUNT_ID: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}
+      CLOUDFLARE_API_TOKEN: ${{ secrets.CLOUDFLARE_API_TOKEN }}
+      FEE_PAYER_PRIVATE_KEY_MAINNET: ${{ secrets.FEE_PAYER_PRIVATE_KEY_MAINNET }}
+      FEE_PAYER_PRIVATE_KEY_TESTNET: ${{ secrets.FEE_PAYER_PRIVATE_KEY_TESTNET }}
+      SECRET_KEY: ${{ secrets.SECRET_KEY }}
+      SLACK_CONFIG_ACCESS_TOKEN: ${{ secrets.SLACK_CONFIG_ACCESS_TOKEN }}
+      SLACK_CONFIG_REFRESH_TOKEN: ${{ secrets.SLACK_CONFIG_REFRESH_TOKEN }}
+      TEMPO_API_KEY: ${{ secrets.TEMPO_API_KEY }}
diff --git a/.github/workflows/preview_destroy.yml b/.github/workflows/preview_destroy.yml
index e1368b2..4b69dc0 100644
--- a/.github/workflows/preview_destroy.yml
+++ b/.github/workflows/preview_destroy.yml
@@ -1,18 +1,14 @@
 name: Preview Destroy
 
-on:
-  pull_request:
+on: # zizmor: ignore[dangerous-triggers] Runs main's workflow and checkout; PR code is never checked out.
+  pull_request_target:
     types: [closed, converted_to_draft]
 
 concurrency:
   group: slack-config-ci
   cancel-in-progress: false
 
-permissions:
-  contents: read
-  id-token: write
-  issues: write
-  pull-requests: write
+permissions: {}
 
 env:
   PREVIEW_APEX: pr${{ github.event.pull_request.number }}
@@ -21,11 +17,35 @@ env:
   WRANGLER_SEND_METRICS: false
 
 jobs:
+  authorize:
+    name: Authorize
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      id-token: write
+    steps:
+      - name: Mint organization membership token
+        id: member_token
+        uses: tempoxyz/gh-actions/actions/github-sts@dd1014bf8244fded7a501e701cafab240a4f9f0e # main
+        with:
+          policy: workflow-member
+
+      - name: Check triggering actor organization membership
+        env:
+          ACTOR: ${{ github.triggering_actor }}
+          GH_TOKEN: ${{ steps.member_token.outputs.token }}
+        run: gh api --silent "orgs/tempoxyz/members/${ACTOR}"
+
   destroy:
     name: Destroy
-    if: contains(fromJSON('["COLLABORATOR", "MEMBER", "OWNER"]'), github.event.pull_request.author_association)
+    needs: authorize
     runs-on: ubuntu-latest
     environment: preview
+    permissions:
+      contents: read
+      id-token: write
+      issues: write
+      pull-requests: write
     steps:
       - name: Read preview state
         id: state
diff --git a/.github/workflows/preview_sweep.yml b/.github/workflows/preview_sweep.yml
index 3b851d0..c30a8e4 100644
--- a/.github/workflows/preview_sweep.yml
+++ b/.github/workflows/preview_sweep.yml
@@ -1,28 +1,52 @@
 name: Preview Sweep
 
 on:
+  repository_dispatch:
+    types: [preview_sweep]
   schedule:
     - cron: '0 0 * * *' # Daily at midnight UTC
-  workflow_dispatch:
 
 concurrency:
   group: slack-config-ci
   cancel-in-progress: false
 
-permissions:
-  contents: read
-  id-token: write
-  issues: write
-  pull-requests: write
+permissions: {}
 
 env:
   WRANGLER_SEND_METRICS: false
 
 jobs:
+  authorize:
+    name: Authorize
+    if: github.event_name == 'repository_dispatch'
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      id-token: write
+    steps:
+      - name: Mint organization membership token
+        id: member_token
+        uses: tempoxyz/gh-actions/actions/github-sts@dd1014bf8244fded7a501e701cafab240a4f9f0e # main
+        with:
+          policy: workflow-member
+
+      - name: Check triggering actor organization membership
+        env:
+          ACTOR: ${{ github.triggering_actor }}
+          GH_TOKEN: ${{ steps.member_token.outputs.token }}
+        run: gh api --silent "orgs/tempoxyz/members/${ACTOR}"
+
   sweep:
     name: Sweep Orphaned Previews
+    if: always() && (github.event_name == 'schedule' || needs.authorize.result == 'success')
+    needs: authorize
     runs-on: ubuntu-latest
     environment: preview
+    permissions:
+      contents: read
+      id-token: write
+      issues: write
+      pull-requests: write
     steps:
       - name: Checkout
         uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
diff --git a/.github/workflows/production.yml b/.github/workflows/production.yml
index 8325be7..874db13 100644
--- a/.github/workflows/production.yml
+++ b/.github/workflows/production.yml
@@ -10,8 +10,28 @@ env:
   WRANGLER_SEND_METRICS: false
 
 jobs:
+  authorize:
+    name: Authorize
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      id-token: write
+    steps:
+      - name: Mint organization membership token
+        id: member_token
+        uses: tempoxyz/gh-actions/actions/github-sts@dd1014bf8244fded7a501e701cafab240a4f9f0e # main
+        with:
+          policy: workflow-member
+
+      - name: Check triggering actor organization membership
+        env:
+          ACTOR: ${{ github.triggering_actor }}
+          GH_TOKEN: ${{ steps.member_token.outputs.token }}
+        run: gh api --silent "orgs/tempoxyz/members/${ACTOR}"
+
   check:
     name: Check
+    needs: authorize
     permissions:
       contents: read
     uses: ./.github/workflows/check.yml
diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
index e9546f6..c4dd82a 100644
--- a/.github/workflows/pull_request.yml
+++ b/.github/workflows/pull_request.yml
@@ -18,27 +18,3 @@ jobs:
   check:
     name: Check
     uses: ./.github/workflows/check.yml
-
-  preview:
-    name: Preview
-    if: github.event.pull_request.draft == false && contains(fromJSON('["COLLABORATOR", "MEMBER", "OWNER"]'), github.event.pull_request.author_association)
-    needs: check
-    permissions:
-      contents: read
-      id-token: write
-      issues: write
-      pull-requests: write
-    uses: ./.github/workflows/preview_deploy.yml
-    with:
-      pr_number: ${{ github.event.pull_request.number }}
-      sha: ${{ github.event.pull_request.head.sha }}
-      twitter_bot_handle: ${{ vars.TWITTER_BOT_HANDLE || 'tipbotgg' }}
-    secrets:
-      CLOUDFLARE_ACCOUNT_ID: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}
-      CLOUDFLARE_API_TOKEN: ${{ secrets.CLOUDFLARE_API_TOKEN }}
-      FEE_PAYER_PRIVATE_KEY_MAINNET: ${{ secrets.FEE_PAYER_PRIVATE_KEY_MAINNET }}
-      FEE_PAYER_PRIVATE_KEY_TESTNET: ${{ secrets.FEE_PAYER_PRIVATE_KEY_TESTNET }}
-      SECRET_KEY: ${{ secrets.SECRET_KEY }}
-      SLACK_CONFIG_ACCESS_TOKEN: ${{ secrets.SLACK_CONFIG_ACCESS_TOKEN }}
-      SLACK_CONFIG_REFRESH_TOKEN: ${{ secrets.SLACK_CONFIG_REFRESH_TOKEN }}
-      TEMPO_API_KEY: ${{ secrets.TEMPO_API_KEY }}
diff --git a/.github/workflows/zizmor.yml b/.github/workflows/zizmor.yml
index afaa946..85fd919 100644
--- a/.github/workflows/zizmor.yml
+++ b/.github/workflows/zizmor.yml
@@ -5,7 +5,6 @@ on:
     branches: ['**']
   push:
     branches: [main]
-  workflow_dispatch:
 
 permissions: {}