diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index ec223d7..8e613b0 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -77,3 +77,19 @@ ggplot(mtcars, aes(x = wt, y = mpg)) +
   labs(x = "Weight (1000 lbs)", y = "Miles per Gallon")
 ```
 ````
+
+## Quality Assurance
+
+### Testing Renders
+
+Before requesting review or marking work as complete:
+
+- **Test your changes locally** by running `quarto render` (or rendering only the touched page with `quarto render <file>.qmd --to html` while iterating).
+- **Check the rendered output** in `_site/` to verify:
+  - All content displays correctly
+  - No broken links or missing images
+  - Formatting is as expected
+- **Review the PR preview** at the preview URL to confirm everything works in the deployed version.
+- **Fix any rendering issues** before requesting review.
+
+This ensures reviewers see working, polished output rather than discovering basic rendering problems.
diff --git a/.github/prompts/quarto-review.prompt.md b/.github/prompts/quarto-review.prompt.md
new file mode 100644
index 0000000..4e70dea
--- /dev/null
+++ b/.github/prompts/quarto-review.prompt.md
@@ -0,0 +1,46 @@
+---
+mode: agent
+description: Quarto-first PR review for this repository — content, rendering correctness, links, and validation gaps. Use when preparing or checking a PR that touches pages, rendering logic, or workflow files.
+---
+
+Review the requested changes as a Quarto-first code review for this repository.
+
+Scope:
+
+- Prioritize changed `.qmd`, `.R`, `.Rmd`, `.yml`, and `.yaml` files.
+- Treat files under `_extensions/` as vendored third-party code. Read them for
+  context if needed, but do not flag or request changes there.
+- Focus on behavior, rendering correctness, broken links or references, and
+  validation gaps.
+
+Review checklist:
+
+1. Links point to source `.qmd` targets, not rendered `.html` files; cross-refs
+   (`@fig-`, `@tbl-`, `@sec-`) resolve to defined labels.
+2. Lists of three or more items use bullets with a blank line above them.
+3. `code-fold: true` is used where the *output* is the point and avoided on
+   tutorial code; chunk options use `#|` directives, not inline `r, opt = val`.
+4. Narrative text does not hard-code computed values — they are computed in a
+   chunk and referenced with inline R.
+5. Citations and attribution are present where adapted content or factual
+   claims appear, and only sources in `references.bib` are used.
+6. No new R package or Quarto extension is added without a clear reason (this is
+   a template — every dependency lands in every downstream book).
+7. No generated files are edited (`README.md` from `README.Rmd`; `_site/`,
+   `_freeze/`, `.quarto/`), and spell/link-check failures are fixed at the
+   source (wordlist or content), not suppressed.
+8. The author ran the required local validation:
+   - render of the touched page
+   - `lintr`
+   - `spelling::spell_check_package()`
+
+Output format:
+
+- Findings first, ordered by severity, with file references.
+- Then open questions or assumptions.
+- Then a short change summary only if useful.
+- If there are no findings, say so explicitly and note any residual testing gaps.
+
+Base the review on [copilot-instructions.md](../copilot-instructions.md) and
+[CLAUDE.md](../../CLAUDE.md), plus any path-scoped rules under
+`.github/instructions/` (if present) that apply to the changed files.
diff --git a/.github/workflows/copilot-setup-steps.yml b/.github/workflows/copilot-setup-steps.yml
index 1608577..a7a94e7 100644
--- a/.github/workflows/copilot-setup-steps.yml
+++ b/.github/workflows/copilot-setup-steps.yml
@@ -11,14 +11,25 @@
 
 name: "Copilot Setup Steps"
 
-# Automatically run the setup steps when they are changed to allow for easy validation,
-# and allow manual testing through the repository's "Actions" tab
+# This workflow has two independent invocation paths:
+#
+#  1. Copilot agent provisioning: GitHub's Copilot coding agent runs the
+#     `copilot-setup-steps` job DIRECTLY to build its environment when it
+#     starts a task. That invocation is NOT governed by the `on:` triggers
+#     below — so the `paths:` filter does not affect it. The `skip-cp-setup`
+#     label short-circuits the heavy install (checkout only) in that context,
+#     so a PR Copilot is working on can opt out of the full setup cost.
+#  2. Validation CI: the `on:` triggers below run the workflow as an ordinary
+#     job, gated to changes of THIS file so we can validate edits to it
+#     without paying the setup cost on every unrelated PR. The
+#     `labeled`/`unlabeled` types let toggling the label re-run a validation.
 on:
   workflow_dispatch:
   push:
     paths:
       - .github/workflows/copilot-setup-steps.yml
   pull_request:
+    types: [opened, synchronize, reopened, labeled, unlabeled]
     paths:
       - .github/workflows/copilot-setup-steps.yml
 
@@ -31,18 +42,42 @@ jobs:
     # Copilot will be given its own token for its operations.
     permissions:
       contents: read
-    
+      pull-requests: read   # read PR labels for the skip-cp-setup check
+
     # Timeout after 55 minutes (max is 59 for copilot-setup-steps)
     timeout-minutes: 55
-    
+
     steps:
+      # Skip the heavy install when a PR carries the `skip-cp-setup` label
+      # (e.g. metadata- or workflow-only PRs). Non-PR events always run setup.
+      - name: Check if setup should be skipped
+        id: check_label
+        # Pass the expression result through env (GitHub-recommended) rather
+        # than interpolating it directly into the shell, to avoid the
+        # expression-injection anti-pattern in code that downstream books copy.
+        env:
+          EVENT_NAME: ${{ github.event_name }}
+          LABELS_CONTAIN_SKIP: ${{ contains(github.event.pull_request.labels.*.name, 'skip-cp-setup') }}
+        shell: bash
+        run: |
+          if [[ "$EVENT_NAME" != 'pull_request' ]]; then
+            echo "Not a pull request, running full setup"
+            echo "skip=false" >> "$GITHUB_OUTPUT"
+          elif [[ "$LABELS_CONTAIN_SKIP" == 'true' ]]; then
+            echo "skip-cp-setup label present, skipping setup steps"
+            echo "skip=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "skip-cp-setup label not present, running full setup"
+            echo "skip=false" >> "$GITHUB_OUTPUT"
+          fi
+
       # Checkout code - Copilot will do this automatically if we don't,
       # but we need it for any repository-specific setup
       - name: Checkout code
         uses: actions/checkout@v4
         with:
           submodules: true
-      
+
       # Install system dependencies needed for this project, including:
       #
       # - C/C++ libraries required by R packages (libcurl, libssl, libxml2, etc.)
@@ -51,6 +86,7 @@ jobs:
       # - A computer algebra system (maxima) for symbolic math computations
       # - Python pip for additional tooling
       - name: Install system dependencies
+        if: steps.check_label.outputs.skip != 'true'
         run: |
           sudo apt-get update
           sudo apt-get install -y \
@@ -74,11 +110,13 @@ jobs:
       
       # Set up pandoc for documentation
       - name: Set up Pandoc
+        if: steps.check_label.outputs.skip != 'true'
         uses: r-lib/actions/setup-pandoc@v2
-      
+
       # Set up R using the standard GitHub Actions setup
       # Using 'release' to get the latest R version
       - name: Set up R
+        if: steps.check_label.outputs.skip != 'true'
         uses: r-lib/actions/setup-r@v2
         with:
           r-version: 'release'
@@ -86,6 +124,7 @@ jobs:
 
       # Install R packages needed for linting and Quarto rendering
       - name: Install R packages
+        if: steps.check_label.outputs.skip != 'true'
         run: |
           install.packages(
             c("lintr", "rmarkdown"),
@@ -95,12 +134,14 @@ jobs:
       
       # Set up Quarto - required for rendering the website
       - name: Set up Quarto
+        if: steps.check_label.outputs.skip != 'true'
         uses: quarto-dev/quarto-actions/setup@v2
         with:
           tinytex: true
-      
+
       # Verify development environment is properly configured
       - name: Verify development environment
+        if: steps.check_label.outputs.skip != 'true'
         run: |
           echo "=== Development Environment Status ==="
           
diff --git a/CLAUDE.md b/CLAUDE.md
index 3500b0d..1d09595 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -33,7 +33,7 @@ Mirrors [`.github/copilot-instructions.md`](.github/copilot-instructions.md). Ke
 ## Working in this repo
 
 - **Don't edit generated files**: `README.md` is built from `README.Rmd`; `_site/` and `_freeze/` are build outputs.
-- **Local preview**: `quarto preview` (live reload). Full build: `quarto render`.
+- **Local preview**: `quarto preview` (live reload). Full build: `quarto render`. When verifying a single edited page, render just that page (`quarto render <file>.qmd --to html`) rather than the whole site — the `/render` command is for the full build.
 - **Submodules**: `macros/` is the only git submodule (see `.gitmodules`). Run `git submodule update --init --recursive` after cloning.
 - **Spell check**: words go in `inst/WORDLIST` (see `.github/workflows/check-spelling.yaml`). Update the wordlist instead of disabling the check.
 - **Link check**: tuned in `lychee.toml`; prefer fixing broken links over adding exceptions.