diff --git a/auth.ts b/auth.ts
index f504374..6b30f84 100644
--- a/auth.ts
+++ b/auth.ts
@@ -303,7 +303,7 @@ export async function authedFetch(
     `token=${auth}; deno_auth_ghid=force`,
   );
 
-  const url = new URL(endpoint, context.endpoint);
+  const url = new URL(`${context.endpoint}/${endpoint}`);
 
   let fallbackBody: ReadableStream | undefined;
   if (init.body instanceof ReadableStream) {
diff --git a/lib/rs_lib.d.ts b/lib/rs_lib.d.ts
new file mode 100644
index 0000000..2a36ee9
--- /dev/null
+++ b/lib/rs_lib.d.ts
@@ -0,0 +1,9 @@
+// @generated file from wasmbuild -- do not edit
+// deno-lint-ignore-file
+// deno-fmt-ignore-file
+
+export function resolve_config(
+  root_path: string,
+  ignore_paths: string[],
+  allow_node_modules: boolean,
+): any;
diff --git a/lib/rs_lib.internal.js b/lib/rs_lib.internal.js
new file mode 100644
index 0000000..63eb5a4
--- /dev/null
+++ b/lib/rs_lib.internal.js
@@ -0,0 +1,441 @@
+// @generated file from wasmbuild -- do not edit
+// @ts-nocheck: generated
+// deno-lint-ignore-file
+// deno-fmt-ignore-file
+
+import { copy_bytes } from "./snippets/sys_traits-4d1fdc43f822dba1/inline0.js";
+
+let wasm;
+export function __wbg_set_wasm(val) {
+  wasm = val;
+}
+
+function addToExternrefTable0(obj) {
+  const idx = wasm.__externref_table_alloc();
+  wasm.__wbindgen_export_2.set(idx, obj);
+  return idx;
+}
+
+function handleError(f, args) {
+  try {
+    return f.apply(this, args);
+  } catch (e) {
+    const idx = addToExternrefTable0(e);
+    wasm.__wbindgen_exn_store(idx);
+  }
+}
+
+const lTextDecoder = typeof TextDecoder === "undefined"
+  ? (0, module.require)("util").TextDecoder
+  : TextDecoder;
+
+let cachedTextDecoder = new lTextDecoder("utf-8", {
+  ignoreBOM: true,
+  fatal: true,
+});
+
+cachedTextDecoder.decode();
+
+let cachedUint8ArrayMemory0 = null;
+
+function getUint8ArrayMemory0() {
+  if (
+    cachedUint8ArrayMemory0 === null || cachedUint8ArrayMemory0.byteLength === 0
+  ) {
+    cachedUint8ArrayMemory0 = new Uint8Array(wasm.memory.buffer);
+  }
+  return cachedUint8ArrayMemory0;
+}
+
+function getStringFromWasm0(ptr, len) {
+  ptr = ptr >>> 0;
+  return cachedTextDecoder.decode(
+    getUint8ArrayMemory0().subarray(ptr, ptr + len),
+  );
+}
+
+function debugString(val) {
+  // primitive types
+  const type = typeof val;
+  if (type == "number" || type == "boolean" || val == null) {
+    return `${val}`;
+  }
+  if (type == "string") {
+    return `"${val}"`;
+  }
+  if (type == "symbol") {
+    const description = val.description;
+    if (description == null) {
+      return "Symbol";
+    } else {
+      return `Symbol(${description})`;
+    }
+  }
+  if (type == "function") {
+    const name = val.name;
+    if (typeof name == "string" && name.length > 0) {
+      return `Function(${name})`;
+    } else {
+      return "Function";
+    }
+  }
+  // objects
+  if (Array.isArray(val)) {
+    const length = val.length;
+    let debug = "[";
+    if (length > 0) {
+      debug += debugString(val[0]);
+    }
+    for (let i = 1; i < length; i++) {
+      debug += ", " + debugString(val[i]);
+    }
+    debug += "]";
+    return debug;
+  }
+  // Test for built-in
+  const builtInMatches = /\[object ([^\]]+)\]/.exec(toString.call(val));
+  let className;
+  if (builtInMatches && builtInMatches.length > 1) {
+    className = builtInMatches[1];
+  } else {
+    // Failed to match the standard '[object ClassName]'
+    return toString.call(val);
+  }
+  if (className == "Object") {
+    // we're a user defined class or Object
+    // JSON.stringify avoids problems with cycles, and is generally much
+    // easier than looping through ownProperties of `val`.
+    try {
+      return "Object(" + JSON.stringify(val) + ")";
+    } catch (_) {
+      return "Object";
+    }
+  }
+  // errors
+  if (val instanceof Error) {
+    return `${val.name}: ${val.message}\n${val.stack}`;
+  }
+  // TODO we could test for more things here, like `Set`s and `Map`s.
+  return className;
+}
+
+let WASM_VECTOR_LEN = 0;
+
+const lTextEncoder = typeof TextEncoder === "undefined"
+  ? (0, module.require)("util").TextEncoder
+  : TextEncoder;
+
+let cachedTextEncoder = new lTextEncoder("utf-8");
+
+const encodeString = typeof cachedTextEncoder.encodeInto === "function"
+  ? function (arg, view) {
+    return cachedTextEncoder.encodeInto(arg, view);
+  }
+  : function (arg, view) {
+    const buf = cachedTextEncoder.encode(arg);
+    view.set(buf);
+    return {
+      read: arg.length,
+      written: buf.length,
+    };
+  };
+
+function passStringToWasm0(arg, malloc, realloc) {
+  if (realloc === undefined) {
+    const buf = cachedTextEncoder.encode(arg);
+    const ptr = malloc(buf.length, 1) >>> 0;
+    getUint8ArrayMemory0().subarray(ptr, ptr + buf.length).set(buf);
+    WASM_VECTOR_LEN = buf.length;
+    return ptr;
+  }
+
+  let len = arg.length;
+  let ptr = malloc(len, 1) >>> 0;
+
+  const mem = getUint8ArrayMemory0();
+
+  let offset = 0;
+
+  for (; offset < len; offset++) {
+    const code = arg.charCodeAt(offset);
+    if (code > 0x7F) break;
+    mem[ptr + offset] = code;
+  }
+
+  if (offset !== len) {
+    if (offset !== 0) {
+      arg = arg.slice(offset);
+    }
+    ptr = realloc(ptr, len, len = offset + arg.length * 3, 1) >>> 0;
+    const view = getUint8ArrayMemory0().subarray(ptr + offset, ptr + len);
+    const ret = encodeString(arg, view);
+
+    offset += ret.written;
+    ptr = realloc(ptr, len, offset, 1) >>> 0;
+  }
+
+  WASM_VECTOR_LEN = offset;
+  return ptr;
+}
+
+let cachedDataViewMemory0 = null;
+
+function getDataViewMemory0() {
+  if (
+    cachedDataViewMemory0 === null ||
+    cachedDataViewMemory0.buffer.detached === true ||
+    (cachedDataViewMemory0.buffer.detached === undefined &&
+      cachedDataViewMemory0.buffer !== wasm.memory.buffer)
+  ) {
+    cachedDataViewMemory0 = new DataView(wasm.memory.buffer);
+  }
+  return cachedDataViewMemory0;
+}
+
+function isLikeNone(x) {
+  return x === undefined || x === null;
+}
+
+function passArrayJsValueToWasm0(array, malloc) {
+  const ptr = malloc(array.length * 4, 4) >>> 0;
+  for (let i = 0; i < array.length; i++) {
+    const add = addToExternrefTable0(array[i]);
+    getDataViewMemory0().setUint32(ptr + 4 * i, add, true);
+  }
+  WASM_VECTOR_LEN = array.length;
+  return ptr;
+}
+
+function takeFromExternrefTable0(idx) {
+  const value = wasm.__wbindgen_export_2.get(idx);
+  wasm.__externref_table_dealloc(idx);
+  return value;
+}
+/**
+ * @param {string} root_path
+ * @param {string[]} ignore_paths
+ * @param {boolean} allow_node_modules
+ * @returns {any}
+ */
+export function resolve_config(root_path, ignore_paths, allow_node_modules) {
+  const ptr0 = passStringToWasm0(
+    root_path,
+    wasm.__wbindgen_malloc,
+    wasm.__wbindgen_realloc,
+  );
+  const len0 = WASM_VECTOR_LEN;
+  const ptr1 = passArrayJsValueToWasm0(ignore_paths, wasm.__wbindgen_malloc);
+  const len1 = WASM_VECTOR_LEN;
+  const ret = wasm.resolve_config(ptr0, len0, ptr1, len1, allow_node_modules);
+  if (ret[2]) {
+    throw takeFromExternrefTable0(ret[1]);
+  }
+  return takeFromExternrefTable0(ret[0]);
+}
+
+const __wbindgen_enum_Os = ["windows", "darwin"];
+
+export function __wbg_byteLength_e674b853d9c77e1d(arg0) {
+  const ret = arg0.byteLength;
+  return ret;
+}
+
+export function __wbg_copybytes_912c72f9e6d5334b(arg0, arg1, arg2) {
+  copy_bytes(arg0, arg1, arg2 >>> 0);
+}
+
+export function __wbg_done_769e5ede4b31c67b(arg0) {
+  const ret = arg0.done;
+  return ret;
+}
+
+export function __wbg_getTime_46267b1c24877e30(arg0) {
+  const ret = arg0.getTime();
+  return ret;
+}
+
+export function __wbg_get_67b2ba62fc30de12() {
+  return handleError(function (arg0, arg1) {
+    const ret = Reflect.get(arg0, arg1);
+    return ret;
+  }, arguments);
+}
+
+export function __wbg_instanceof_Date_e9a9be8b9cea7890(arg0) {
+  let result;
+  try {
+    result = arg0 instanceof Date;
+  } catch (_) {
+    result = false;
+  }
+  const ret = result;
+  return ret;
+}
+
+export function __wbg_instanceof_Error_4d54113b22d20306(arg0) {
+  let result;
+  try {
+    result = arg0 instanceof Error;
+  } catch (_) {
+    result = false;
+  }
+  const ret = result;
+  return ret;
+}
+
+export function __wbg_lstatSync_ffcaae096515e955() {
+  return handleError(function (arg0, arg1) {
+    const ret = Deno.lstatSync(getStringFromWasm0(arg0, arg1));
+    return ret;
+  }, arguments);
+}
+
+export function __wbg_message_97a2af9b89d693a3(arg0) {
+  const ret = arg0.message;
+  return ret;
+}
+
+export function __wbg_name_0b327d569f00ebee(arg0) {
+  const ret = arg0.name;
+  return ret;
+}
+
+export function __wbg_new_405e22f390576ce2() {
+  const ret = new Object();
+  return ret;
+}
+
+export function __wbg_new_78feb108b6472713() {
+  const ret = new Array();
+  return ret;
+}
+
+export function __wbg_next_6574e1a8a62d1055() {
+  return handleError(function (arg0) {
+    const ret = arg0.next();
+    return ret;
+  }, arguments);
+}
+
+export function __wbg_readDirSync_6627a121ad5b5202() {
+  return handleError(function (arg0, arg1) {
+    const ret = Deno.readDirSync(getStringFromWasm0(arg0, arg1));
+    return ret;
+  }, arguments);
+}
+
+export function __wbg_readFileSync_d8dc373cf87d2f9e() {
+  return handleError(function (arg0, arg1) {
+    const ret = Deno.readFileSync(getStringFromWasm0(arg0, arg1));
+    return ret;
+  }, arguments);
+}
+
+export function __wbg_set_37837023f3d740e8(arg0, arg1, arg2) {
+  arg0[arg1 >>> 0] = arg2;
+}
+
+export function __wbg_set_3f1d0b984ed272ed(arg0, arg1, arg2) {
+  arg0[arg1] = arg2;
+}
+
+export function __wbg_statSync_af9d1d3acb9d8325() {
+  return handleError(function (arg0, arg1) {
+    const ret = Deno.statSync(getStringFromWasm0(arg0, arg1));
+    return ret;
+  }, arguments);
+}
+
+export function __wbg_static_accessor_BUILD_OS_57f049863cca4b6a() {
+  const ret = Deno.build.os;
+  return (__wbindgen_enum_Os.indexOf(ret) + 1 || 3) - 1;
+}
+
+export function __wbg_value_cd1ffa7b1ab794f1(arg0) {
+  const ret = arg0.value;
+  return ret;
+}
+
+export function __wbindgen_boolean_get(arg0) {
+  const v = arg0;
+  const ret = typeof v === "boolean" ? (v ? 1 : 0) : 2;
+  return ret;
+}
+
+export function __wbindgen_debug_string(arg0, arg1) {
+  const ret = debugString(arg1);
+  const ptr1 = passStringToWasm0(
+    ret,
+    wasm.__wbindgen_malloc,
+    wasm.__wbindgen_realloc,
+  );
+  const len1 = WASM_VECTOR_LEN;
+  getDataViewMemory0().setInt32(arg0 + 4 * 1, len1, true);
+  getDataViewMemory0().setInt32(arg0 + 4 * 0, ptr1, true);
+}
+
+export function __wbindgen_error_new(arg0, arg1) {
+  const ret = new Error(getStringFromWasm0(arg0, arg1));
+  return ret;
+}
+
+export function __wbindgen_init_externref_table() {
+  const table = wasm.__wbindgen_export_2;
+  const offset = table.grow(4);
+  table.set(0, undefined);
+  table.set(offset + 0, undefined);
+  table.set(offset + 1, null);
+  table.set(offset + 2, true);
+  table.set(offset + 3, false);
+}
+
+export function __wbindgen_is_bigint(arg0) {
+  const ret = typeof arg0 === "bigint";
+  return ret;
+}
+
+export function __wbindgen_is_null(arg0) {
+  const ret = arg0 === null;
+  return ret;
+}
+
+export function __wbindgen_is_undefined(arg0) {
+  const ret = arg0 === undefined;
+  return ret;
+}
+
+export function __wbindgen_memory() {
+  const ret = wasm.memory;
+  return ret;
+}
+
+export function __wbindgen_number_get(arg0, arg1) {
+  const obj = arg1;
+  const ret = typeof obj === "number" ? obj : undefined;
+  getDataViewMemory0().setFloat64(
+    arg0 + 8 * 1,
+    isLikeNone(ret) ? 0 : ret,
+    true,
+  );
+  getDataViewMemory0().setInt32(arg0 + 4 * 0, !isLikeNone(ret), true);
+}
+
+export function __wbindgen_string_get(arg0, arg1) {
+  const obj = arg1;
+  const ret = typeof obj === "string" ? obj : undefined;
+  var ptr1 = isLikeNone(ret)
+    ? 0
+    : passStringToWasm0(ret, wasm.__wbindgen_malloc, wasm.__wbindgen_realloc);
+  var len1 = WASM_VECTOR_LEN;
+  getDataViewMemory0().setInt32(arg0 + 4 * 1, len1, true);
+  getDataViewMemory0().setInt32(arg0 + 4 * 0, ptr1, true);
+}
+
+export function __wbindgen_string_new(arg0, arg1) {
+  const ret = getStringFromWasm0(arg0, arg1);
+  return ret;
+}
+
+export function __wbindgen_throw(arg0, arg1) {
+  throw new Error(getStringFromWasm0(arg0, arg1));
+}
diff --git a/lib/rs_lib.js b/lib/rs_lib.js
new file mode 100644
index 0000000..3801691
--- /dev/null
+++ b/lib/rs_lib.js
@@ -0,0 +1,12 @@
+// @generated file from wasmbuild -- do not edit
+// @ts-nocheck: generated
+// deno-lint-ignore-file
+// deno-fmt-ignore-file
+// @ts-self-types="./rs_lib.d.ts"
+
+// source-hash: 68956057249f7e95a1e18a1449d2b9195b60bd6f
+import * as wasm from "./rs_lib.wasm";
+export * from "./rs_lib.internal.js";
+import { __wbg_set_wasm } from "./rs_lib.internal.js";
+__wbg_set_wasm(wasm);
+wasm.__wbindgen_start();
diff --git a/lib/rs_lib.wasm b/lib/rs_lib.wasm
new file mode 100644
index 0000000..6bd094f
Binary files /dev/null and b/lib/rs_lib.wasm differ
diff --git a/lib/snippets/sys_traits-4d1fdc43f822dba1/inline0.js b/lib/snippets/sys_traits-4d1fdc43f822dba1/inline0.js
new file mode 100644
index 0000000..75a0b13
--- /dev/null
+++ b/lib/snippets/sys_traits-4d1fdc43f822dba1/inline0.js
@@ -0,0 +1 @@
+export function copy_bytes(from, to, dst) { new Uint8Array(to.buffer).set(from, dst) }
\ No newline at end of file
diff --git a/tests/url_resolution.test.ts b/tests/url_resolution.test.ts
new file mode 100644
index 0000000..57d86df
--- /dev/null
+++ b/tests/url_resolution.test.ts
@@ -0,0 +1,40 @@
+import { assertEquals } from "@std/assert";
+
+// Reproduces the URL resolution behavior in authedFetch.
+// Before the fix: new URL(endpoint, base) drops path segments from the base.
+// After the fix: string concatenation preserves the full base path.
+
+Deno.test("new URL() two-arg drops base path segments", () => {
+  // This is the OLD (broken) behavior that motivates the fix.
+  // When the endpoint is a proxy URL with a path, the path-based
+  // target host segment gets silently dropped.
+  const base = "https://proxy.example.com/target-host";
+  const endpoint = "api/diffsync/org/app/rev123";
+
+  const broken = new URL(endpoint, base);
+  // new URL resolves relative to the parent of "target-host", losing it:
+  assertEquals(broken.pathname, "/api/diffsync/org/app/rev123");
+  // "target-host" is gone — the proxy can no longer route the request.
+});
+
+Deno.test("string concatenation preserves base path segments", () => {
+  // This is the FIXED behavior: concatenation keeps the full base path.
+  const base = "https://proxy.example.com/target-host";
+  const endpoint = "api/diffsync/org/app/rev123";
+
+  const fixed = new URL(`${base}/${endpoint}`);
+  assertEquals(
+    fixed.pathname,
+    "/target-host/api/diffsync/org/app/rev123",
+  );
+});
+
+Deno.test("string concatenation works for standard endpoint too", () => {
+  // Ensure the fix doesn't regress the normal (non-proxy) case.
+  const base = "https://console.deno.com";
+  const endpoint = "api/diffsync/org/app/rev123";
+
+  const fixed = new URL(`${base}/${endpoint}`);
+  assertEquals(fixed.pathname, "/api/diffsync/org/app/rev123");
+  assertEquals(fixed.hostname, "console.deno.com");
+});
diff --git a/util.ts b/util.ts
index 85a03b5..21cd0b8 100644
--- a/util.ts
+++ b/util.ts
@@ -23,7 +23,9 @@ export function error(
 ): never {
   console.error();
   console.error(`${red("✗")} An error occurred:`);
-  console.error(`  ${error.replaceAll("\n", "\n  ")}`);
+  console.error(
+    `  ${String(error ?? "Unknown error").replaceAll("\n", "\n  ")}`,
+  );
   const trace = response?.headers.get("x-deno-trace-id");
   if (context.debug) {
     console.error(`  stack:\n${new Error().stack}`);