diff --git a/packages/shared/src/routine-variables.test.ts b/packages/shared/src/routine-variables.test.ts
index a129ee48..15d63a65 100644
--- a/packages/shared/src/routine-variables.test.ts
+++ b/packages/shared/src/routine-variables.test.ts
@@ -76,6 +76,31 @@ describe("routine variable helpers", () => {
     ]);
   });
 
+  it("extracts snake_case variable names", () => {
+    expect(extractRoutineVariableNames("Open {{pr_url}} for review")).toEqual(["pr_url"]);
+  });
+
+  it("extracts variable names whose underscores were markdown-escaped by a WYSIWYG editor", () => {
+    // MDXEditor / mdast-util-to-markdown defensively escape intraword underscores
+    // when serializing rich-text back to markdown, so `{{pr_url}}` is stored as `{{pr\_url}}`.
+    expect(extractRoutineVariableNames("Open {{pr\\_url}} for review")).toEqual(["pr_url"]);
+    expect(extractRoutineVariableNames("{{pr\\_url\\_v2}}")).toEqual(["pr_url_v2"]);
+  });
+
+  it("syncRoutineVariablesWithTemplate handles markdown-escaped underscores", () => {
+    expect(
+      syncRoutineVariablesWithTemplate("Open {{pr\\_url}}", []),
+    ).toEqual([
+      { name: "pr_url", label: null, type: "text", defaultValue: null, required: true, options: [] },
+    ]);
+  });
+
+  it("interpolates variables that appear with markdown-escaped underscores", () => {
+    expect(
+      interpolateRoutineTemplate("Open {{pr\\_url}}", { pr_url: "https://example.com" }),
+    ).toBe("Open https://example.com");
+  });
+
   it("interpolates built-in variables alongside user variables", () => {
     const builtins = getBuiltinRoutineVariableValues();
     const allVars = { ...builtins, repo: "paperclip" };
diff --git a/packages/shared/src/routine-variables.ts b/packages/shared/src/routine-variables.ts
index b83148d4..84257188 100644
--- a/packages/shared/src/routine-variables.ts
+++ b/packages/shared/src/routine-variables.ts
@@ -1,6 +1,14 @@
 import type { RoutineVariable } from "./types/routine.js";
 
-const ROUTINE_VARIABLE_MATCHER = /\{\{\s*([A-Za-z][A-Za-z0-9_]*)\s*\}\}/g;
+// Tolerate markdown-escaped underscores (`\_`) inside placeholders. WYSIWYG markdown
+// editors (e.g. MDXEditor) serialize `_` between word chars as `\_` to prevent
+// reparse-as-emphasis, so a user-typed `{{pr_url}}` is stored as `{{pr\_url}}`.
+const ROUTINE_VARIABLE_MATCHER = /\{\{\s*([A-Za-z](?:\\_|[A-Za-z0-9_])*)\s*\}\}/g;
+
+function unescapeRoutineVariableName(raw: string): string {
+  return raw.replace(/\\_/g, "_");
+}
+
 type RoutineTemplateInput = string | null | undefined | Array<string | null | undefined>;
 
 /**
@@ -50,7 +58,7 @@ export function extractRoutineVariableNames(template: RoutineTemplateInput): str
   const found = new Set<string>();
   for (const source of normalizeRoutineTemplateInput(template)) {
     for (const match of source.matchAll(ROUTINE_VARIABLE_MATCHER)) {
-      const name = match[1];
+      const name = match[1] ? unescapeRoutineVariableName(match[1]) : "";
       if (name && !found.has(name)) {
         found.add(name);
       }
@@ -97,7 +105,8 @@ export function interpolateRoutineTemplate(
   if (template == null) return null;
   if (!values || Object.keys(values).length === 0) return template;
   return template.replace(ROUTINE_VARIABLE_MATCHER, (match, rawName: string) => {
-    if (!(rawName in values)) return match;
-    return stringifyRoutineVariableValue(values[rawName]);
+    const name = unescapeRoutineVariableName(rawName);
+    if (!(name in values)) return match;
+    return stringifyRoutineVariableValue(values[name]);
   });
 }