diff --git a/src/post/post.ts b/src/post/post.ts
index 3886e5c..90ae232 100644
--- a/src/post/post.ts
+++ b/src/post/post.ts
@@ -28,6 +28,11 @@ const VERDICTS = new Map<string, [event: string, mark: string]>([
 ]);
 const PROFILE_TYPES = new Set<unknown>(["CLAUDE", "CODEX", "OPENCODE"]);
 const FAILURE_REASONS = new Set<unknown>(["SIGN_IN_FAILED", "USAGE_EXHAUSTED", "FAILED"]);
+// Anchors written before the UPPER_SNAKE switch spell sides in lowercase.
+const OLD_SIDES = new Map<unknown, Anchor["side"]>([
+  ["new", "NEW"],
+  ["old", "OLD"],
+]);
 const isProfileType = (value: unknown): value is ProfileFailure["type"] => PROFILE_TYPES.has(value);
 const isFailureReason = (value: unknown): value is FailureReason => FAILURE_REASONS.has(value);
 const failureComment = (failures: ProfileFailure[]): string =>
@@ -56,7 +61,7 @@ function parseAnchors(text: string, sourcePath: string): Anchor[] {
     const path = field(entry, "path");
     const line = field(entry, "line");
     const givenSide = field(entry, "side");
-    const side = givenSide === undefined ? "NEW" : givenSide;
+    const side = givenSide === undefined ? "NEW" : (OLD_SIDES.get(givenSide) ?? givenSide);
     const body = field(entry, "body");
     if (typeof path !== "string" || path === "") {
       throw new TypeError(`${at}.path: expected a repository path`);
diff --git a/src/runtime/credentials.test.ts b/src/runtime/credentials.test.ts
index ef9b43d..2508e5d 100644
--- a/src/runtime/credentials.test.ts
+++ b/src/runtime/credentials.test.ts
@@ -65,3 +65,14 @@ test("rejects malformed central credentials", async () => {
     ),
   ).rejects.toThrow("profiles[0].token");
 });
+
+test("reads lowercase profile types from older credentials", async () => {
+  const credentials = await parseCredentials(
+    JSON.stringify({
+      "reviewer-token": ENCRYPTED,
+      profiles: [{ type: "codex" }, { type: "claude", token: ENCRYPTED }],
+    }),
+    MASTER_KEY,
+  );
+  expect(credentials.profiles.map(({ type }) => type)).toStrictEqual(["CODEX", "CLAUDE"]);
+});
diff --git a/src/runtime/credentials.ts b/src/runtime/credentials.ts
index 3cf4fd0..3e9634a 100644
--- a/src/runtime/credentials.ts
+++ b/src/runtime/credentials.ts
@@ -78,6 +78,17 @@ export async function encryptCredential(
   return `v1:${encodeBase64Url(nonce)}:${encodeBase64Url(new Uint8Array(ciphertext))}`;
 }
 
+// profiles.json files written before the UPPER_SNAKE switch spell types in lowercase.
+const OLD_PROFILE_TYPES = new Map<unknown, BotProfile["type"]>([
+  ["claude", "CLAUDE"],
+  ["codex", "CODEX"],
+  ["opencode", "OPENCODE"],
+]);
+
+function currentSpelling(type: unknown): unknown {
+  return OLD_PROFILE_TYPES.get(type) ?? type;
+}
+
 async function parseProfile(entry: unknown, index: number, masterKey: string): Promise<BotProfile> {
   const at = `profiles[${index}]`;
   if (!isMapping(entry)) {
@@ -88,7 +99,7 @@ async function parseProfile(entry: unknown, index: number, masterKey: string): P
       throw new Error(`${at}.${key}: unknown field`);
     }
   }
-  const type = field(entry, "type");
+  const type = currentSpelling(field(entry, "type"));
   const model = field(entry, "model");
   const token = field(entry, "token");
   if (type !== "CLAUDE" && type !== "CODEX" && type !== "OPENCODE") {