diff --git a/.github/instructions/markdown.instructions.md b/.github/instructions/markdown.instructions.md
new file mode 100644
index 000000000..e6ff61522
--- /dev/null
+++ b/.github/instructions/markdown.instructions.md
@@ -0,0 +1,88 @@
+---
+file_type: "instructions"
+title: "Markdown Instructions (Repo-local)"
+description: "Canonical Markdown authoring rules for the LightSpeed .github control-plane repository."
+version: "v1.0"
+last_updated: "2026-05-26"
+owners: ["LightSpeed Team"]
+tags: ["markdown", "documentation", "a11y", "governance"]
+applyTo: ["**/*.md"]
+status: "active"
+stability: "stable"
+domain: "governance"
+---
+
+# Markdown Instructions (Repo-local)
+
+This file is the canonical Markdown standard for repo-local `.github` documentation.
+For portable and organisation-wide rules, use [`../../instructions/documentation-formats.instructions.md`](../../instructions/documentation-formats.instructions.md).
+
+## Scope
+
+| Scope | File family | Canonical source |
+| --- | --- | --- |
+| Repo-local `.github` docs | `.github/**.md`, `docs/**.md` | This file |
+| Portable shared standards | `instructions/**` | `instructions/documentation-formats.instructions.md` |
+
+## Core Rules
+
+- Use one H1 per file and keep heading levels sequential.
+- Use fenced code blocks with language tags.
+- Keep links relative for in-repo files and verify they resolve.
+- Use `1.` numbering for ordered lists and `-` for unordered lists.
+- Keep wording in UK English.
+
+## Accessibility
+
+- Provide descriptive alt text for images.
+- Ensure table headings are explicit and readable.
+- For Mermaid diagrams, use readable labels and avoid low-contrast palettes.
+- Write link text that describes destination and purpose.
+
+## Validation
+
+Run these checks before merging Markdown changes:
+
+```bash
+npm run lint:md
+git diff --check
+```
+
+## Examples
+
+Good heading flow:
+
+```markdown
+# Title
+
+## Section
+
+### Detail
+```
+
+Good code block:
+
+```markdown
+
+```bash
+npm run lint:md
+```
+
+```
+
+## Contribution And Review
+
+- Keep edits scoped to the issue.
+- Add a short rationale in the PR description.
+- Cross-link related standards when introducing new conventions.
+
+## Cross-References
+
+- [`../../instructions/documentation-formats.instructions.md`](../../instructions/documentation-formats.instructions.md)
+- [`../../instructions/community-standards.instructions.md`](../../instructions/community-standards.instructions.md)
+- [`../../instructions/quality-assurance.instructions.md`](../../instructions/quality-assurance.instructions.md)
+- [`./file-organisation.instructions.md`](./file-organisation.instructions.md)
+
+---
+
+*Maintained by the LightSpeedWP automation and governance maintainers.*
diff --git a/.github/workflows/labeling.yml b/.github/workflows/labeling.yml
index 2e0983195..81765b4ca 100644
--- a/.github/workflows/labeling.yml
+++ b/.github/workflows/labeling.yml
@@ -57,7 +57,6 @@ jobs:
         uses: actions/checkout@v4
         with:
           fetch-depth: 0
-          ref: develop
 
       - name: Setup Node
         uses: actions/setup-node@v4
diff --git a/scripts/agents/labeling.agent.js b/scripts/agents/labeling.agent.js
index f9b33071f..e06b7d42b 100644
--- a/scripts/agents/labeling.agent.js
+++ b/scripts/agents/labeling.agent.js
@@ -83,9 +83,9 @@ const KEYWORD_TYPE_MAP = {
   ci: "type:ci",
   "continuous integration": "type:ci",
   workflow: "type:ci",
-  a11y: "type:accessibility",
-  accessibility: "type:accessibility",
-  wcag: "type:accessibility",
+  a11y: "type:a11y",
+  accessibility: "type:a11y",
+  wcag: "type:a11y",
 };
 
 // Branch prefix to type mapping for PRs
@@ -105,7 +105,7 @@ const BRANCH_PREFIX_TYPE_MAP = {
   "ci/": "type:ci",
   "deps/": "type:dependencies",
   "security/": "type:security",
-  "a11y/": "type:accessibility",
+  "a11y/": "type:a11y",
 };
 
 function readYamlArrayFile(path, purpose) {
@@ -376,7 +376,11 @@ async function runLabelingAgent(opts = {}) {
       try {
         const branchName = context.payload.pull_request.head.ref;
         const branchType = detectTypeFromBranch(branchName);
-        if (branchType && !currentLabels.includes(branchType)) {
+        if (
+          branchType &&
+          canonicalSet.has(branchType) &&
+          !currentLabels.includes(branchType)
+        ) {
           if (!dryRun) {
             await octokit.rest.issues.addLabels({
               owner,
@@ -387,6 +391,10 @@ async function runLabelingAgent(opts = {}) {
           }
           report.added.push(branchType);
           report.rulesApplied.push(`Branch prefix detection: ${branchType}`);
+        } else if (branchType && !canonicalSet.has(branchType)) {
+          core.warning(
+            `[labeling.agent] Branch-derived type is non-canonical and will be skipped: ${branchType}`,
+          );
         }
       } catch (error) {
         core.warning(
@@ -468,7 +476,7 @@ async function runLabelingAgent(opts = {}) {
           : context.payload.pull_request.body;
         const detectedType = detectIssueTypeFromContent(title, body);
 
-        if (detectedType) {
+        if (detectedType && canonicalSet.has(detectedType)) {
           if (!dryRun) {
             await octokit.rest.issues.addLabels({
               owner,
@@ -481,6 +489,10 @@ async function runLabelingAgent(opts = {}) {
           report.rulesApplied.push(
             `Content-based type detection: ${detectedType}`,
           );
+        } else if (detectedType && !canonicalSet.has(detectedType)) {
+          core.warning(
+            `[labeling.agent] Content-derived type is non-canonical and will be skipped: ${detectedType}`,
+          );
         }
       } catch (error) {
         core.warning(