diff --git a/src/mcp.ts b/src/mcp.ts
index c1de334..2cfead1 100644
--- a/src/mcp.ts
+++ b/src/mcp.ts
@@ -1283,7 +1283,7 @@ export class RagMcpAgentV2 extends McpAgent<Env, unknown, McpProps> {
         const itemRepo = row.repo ?? fallbackRepo ?? "";
         const ext = row.wiki_extension || "md";
         if (!pageName || !itemRepo) return;
-        const url = `https://raw.githubusercontent.com/wiki/${itemRepo}/master/${encodeURIComponent(pageName)}.${ext}`;
+        const url = `https://raw.githubusercontent.com/wiki/${itemRepo}/${encodeURIComponent(pageName)}.${ext}`;
         try {
           const res = await fetch(url, {
             headers: { "User-Agent": "github-rag-mcp/0.1.0" },
diff --git a/src/poller.ts b/src/poller.ts
index 86b9d3c..5498a93 100644
--- a/src/poller.ts
+++ b/src/poller.ts
@@ -901,7 +901,8 @@ async function listWikiPages(repo: string): Promise<string[]> {
 /**
  * Fetch a wiki page's raw markup content.
  *
- * GitHub serves wiki content from `raw.githubusercontent.com/wiki/{repo}/master/{page}.{ext}`.
+ * GitHub serves wiki content from `raw.githubusercontent.com/wiki/{repo}/{page}.{ext}`
+ * (no branch segment — wiki raw URLs route directly without referencing master/main).
  * If `preferredExtension` is provided (i.e. the page is already known from a
  * previous poll), try it first to skip the multi-extension probe. Otherwise
  * iterate through every supported extension until one returns 200.
@@ -919,7 +920,7 @@ async function fetchWikiContent(
     : Array.from(WIKI_EXTENSIONS);
 
   for (const ext of probes) {
-    const url = `https://raw.githubusercontent.com/wiki/${repo}/master/${encodeURIComponent(pageName)}.${ext}`;
+    const url = `https://raw.githubusercontent.com/wiki/${repo}/${encodeURIComponent(pageName)}.${ext}`;
     try {
       const resp = await fetch(url, {
         headers: { "User-Agent": "github-rag-mcp/0.1.0" },