diff --git a/.github/workflows/on-pull-request.yml b/.github/workflows/on-pull-request.yml
index 6b263a4f..7a41557a 100644
--- a/.github/workflows/on-pull-request.yml
+++ b/.github/workflows/on-pull-request.yml
@@ -2,9 +2,9 @@ name: Node.js CI
 
 on:
     push:
-        branches: ["main"]
+        branches: ["main", "pretext"]
     pull_request:
-        branches: ["main"]
+        branches: ["main", "pretext"]
 
 jobs:
     build:
diff --git a/packages/unified-latex-to-pretext/libs/pre-conversion-subs/expand-user-defined-macros.ts b/packages/unified-latex-to-pretext/libs/pre-conversion-subs/expand-user-defined-macros.ts
new file mode 100644
index 00000000..2c241d01
--- /dev/null
+++ b/packages/unified-latex-to-pretext/libs/pre-conversion-subs/expand-user-defined-macros.ts
@@ -0,0 +1,49 @@
+import * as Ast from "@unified-latex/unified-latex-types";
+import {
+    expandMacrosExcludingDefinitions,
+    listNewcommands,
+} from "@unified-latex/unified-latex-util-macros";
+import { attachMacroArgs } from "@unified-latex/unified-latex-util-arguments";
+import { anyMacro } from "@unified-latex/unified-latex-util-match";
+import { EXIT, visit } from "@unified-latex/unified-latex-util-visit";
+
+type NewCommandSpec = ReturnType<typeof listNewcommands>[number];
+
+/**
+ * Expands user-defined macros
+ */
+export function expandUserDefinedMacros(ast: Ast.Ast): void {
+    const newcommands = listNewcommands(ast);
+
+    // get a set of all macros to be expanded
+    const macrosToExpand = new Set(newcommands.map((command) => command.name));
+
+    const macroInfo = Object.fromEntries(
+        newcommands.map((m) => [m.name, { signature: m.signature }])
+    );
+
+    // recursively expand at most 100 times
+    for (let i = 0; i < 100; i++) {
+        // check if any macros still need expanding
+        if (!needToExpand(ast, macrosToExpand)) {
+            break;
+        }
+
+        // attach the arguments to each macro before processing it
+        attachMacroArgs(ast, macroInfo);
+        expandMacrosExcludingDefinitions(ast, newcommands);
+    }
+}
+
+function needToExpand(ast: Ast.Ast, macros: Set<string>): boolean {
+    let needExpand = false;
+
+    visit(ast, (node) => {
+        if (anyMacro(node) && macros.has(node.content)) {
+            needExpand = true;
+            EXIT;
+        }
+    });
+
+    return needExpand;
+}
diff --git a/packages/unified-latex-to-pretext/libs/pre-conversion-subs/report-unsupported-macro-katex.ts b/packages/unified-latex-to-pretext/libs/pre-conversion-subs/report-unsupported-macro-katex.ts
new file mode 100644
index 00000000..38651036
--- /dev/null
+++ b/packages/unified-latex-to-pretext/libs/pre-conversion-subs/report-unsupported-macro-katex.ts
@@ -0,0 +1,27 @@
+import * as Ast from "@unified-latex/unified-latex-types";
+import { anyMacro, match } from "@unified-latex/unified-latex-util-match";
+import { visit } from "@unified-latex/unified-latex-util-visit";
+import { KATEX_SUPPORT } from "./katex-subs";
+
+/**
+ * Return a list of macros used in ast that are unsupported by KaTeX
+ */
+export function reportMacrosUnsupportedByKatex(ast: Ast.Ast): string[] {
+    const unsupported: string[] = [];
+
+    // match a macro supported by Katex
+    const isSupported = match.createMacroMatcher(KATEX_SUPPORT.macros);
+
+    // visit all nodes
+    visit(ast, (node, info) => {
+        // macro in math mode
+        if (anyMacro(node) && info.context.hasMathModeAncestor) {
+            // check if not supported by katex
+            if (!isSupported(node)) {
+                unsupported.push((node as Ast.Macro).content);
+            }
+        }
+    });
+
+    return unsupported;
+}
diff --git a/packages/unified-latex-to-pretext/tests/expand-user-defined-macros.test.ts b/packages/unified-latex-to-pretext/tests/expand-user-defined-macros.test.ts
new file mode 100644
index 00000000..6a31b1b7
--- /dev/null
+++ b/packages/unified-latex-to-pretext/tests/expand-user-defined-macros.test.ts
@@ -0,0 +1,74 @@
+import { describe, it, expect } from "vitest";
+import util from "util";
+import { getParser } from "@unified-latex/unified-latex-util-parse";
+import { printRaw } from "@unified-latex/unified-latex-util-print-raw";
+import { expandUserDefinedMacros } from "@unified-latex/unified-latex-to-pretext/libs/pre-conversion-subs/expand-user-defined-macros";
+
+// Make console.log pretty-print by default
+const origLog = console.log;
+console.log = (...args) => {
+    origLog(...args.map((x) => util.inspect(x, false, 10, true)));
+};
+
+describe("unified-latex-to-pretext:expand-user-deifned-macros", () => {
+    let value: string;
+
+    it("can expand newcommand", () => {
+        value = String.raw`\newcommand{\foo}{\bar} \foo`;
+
+        const parser = getParser();
+        const ast = parser.parse(value);
+
+        expandUserDefinedMacros(ast);
+
+        expect(printRaw(ast)).toEqual(String.raw`\newcommand{\foo}{\bar} \bar`);
+    });
+
+    it("can expand renewcommand", () => {
+        value = String.raw`\renewcommand{\O}{\mathcal{O}} \O`;
+
+        const parser = getParser();
+        const ast = parser.parse(value);
+
+        expandUserDefinedMacros(ast);
+
+        expect(printRaw(ast)).toEqual(
+            String.raw`\renewcommand{\O}{\mathcal{O}} \mathcal{O}`
+        );
+    });
+
+    it("can recursively expand multiple user-defined commands", () => {
+        value =
+            String.raw`\newcommand{\join}{\vee}` +
+            String.raw`\join` +
+            String.raw`\renewcommand{\vee}{\foo}` +
+            String.raw`\vee` +
+            String.raw`\renewcommand{\foo}{\bar}` +
+            String.raw`\foo`;
+
+        const parser = getParser();
+        const ast = parser.parse(value);
+
+        expandUserDefinedMacros(ast);
+
+        expect(printRaw(ast)).toEqual(
+            String.raw`\newcommand{\join}{\vee}` +
+                String.raw`\bar` +
+                String.raw`\renewcommand{\vee}{\foo}` +
+                String.raw`\bar` +
+                String.raw`\renewcommand{\foo}{\bar}` +
+                String.raw`\bar`
+        );
+    });
+
+    it("can expand providecommand", () => {
+        value = String.raw`\providecommand{\bar}{\b} \bar`;
+
+        const parser = getParser();
+        const ast = parser.parse(value);
+
+        expandUserDefinedMacros(ast);
+
+        expect(printRaw(ast)).toEqual(String.raw`\providecommand{\bar}{\b} \b`);
+    });
+});
diff --git a/packages/unified-latex-to-pretext/tests/report-unsupported-macro-katex.test.ts b/packages/unified-latex-to-pretext/tests/report-unsupported-macro-katex.test.ts
new file mode 100644
index 00000000..be40a3d8
--- /dev/null
+++ b/packages/unified-latex-to-pretext/tests/report-unsupported-macro-katex.test.ts
@@ -0,0 +1,71 @@
+import { describe, it, expect } from "vitest";
+import util from "util";
+import { getParser } from "@unified-latex/unified-latex-util-parse";
+import { reportMacrosUnsupportedByKatex } from "@unified-latex/unified-latex-to-pretext/libs/pre-conversion-subs/report-unsupported-macro-katex";
+
+// Make console.log pretty-print by default
+const origLog = console.log;
+console.log = (...args) => {
+    origLog(...args.map((x) => util.inspect(x, false, 10, true)));
+};
+
+describe("unified-latex-to-pretext:report-unsupported-macro-katex", () => {
+    let value: string;
+
+    it("can report unsupported macros in inline mathmode", () => {
+        value = String.raw`$\mathbb{R} \fakemacro{X}$`;
+
+        const parser = getParser();
+        const ast = parser.parse(value);
+
+        expect(reportMacrosUnsupportedByKatex(ast)).toEqual(["fakemacro"]);
+    });
+
+    it("can report no unsupported macros in mathmode", () => {
+        value = String.raw`$\mathbb{R} \frac{1}{2} \cup$`;
+
+        const parser = getParser();
+        const ast = parser.parse(value);
+
+        expect(reportMacrosUnsupportedByKatex(ast)).toEqual([]);
+    });
+
+    it("doesn't report unsupported macros outside of math mode", () => {
+        value = String.raw`\fakemacro`;
+
+        const parser = getParser();
+        const ast = parser.parse(value);
+
+        expect(reportMacrosUnsupportedByKatex(ast)).toEqual([]);
+    });
+
+    it("reports unsupported macros in text mode with a math anscestor", () => {
+        value = String.raw`$\frac{1}{\text{ hi \unsupported}}$`;
+
+        const parser = getParser();
+        const ast = parser.parse(value);
+
+        expect(reportMacrosUnsupportedByKatex(ast)).toEqual(["unsupported"]);
+    });
+
+    it("can report unsupported macros in display mathmode", () => {
+        value = String.raw`\[ \frac{a}{b} \fake \text{bar \baz}\] \bang`;
+
+        const parser = getParser();
+        const ast = parser.parse(value);
+
+        expect(reportMacrosUnsupportedByKatex(ast)).toEqual(["fake", "baz"]);
+    });
+
+    it("can report unsupported macros in equation environment", () => {
+        value = String.raw`\unsupported \begin{equation} \mathbb{N} \unsupported \text{\baz}\end{equation}`;
+
+        const parser = getParser();
+        const ast = parser.parse(value);
+
+        expect(reportMacrosUnsupportedByKatex(ast)).toEqual([
+            "unsupported",
+            "baz",
+        ]);
+    });
+});