From 158db6fa8d384ee7d04718d4da813dc7dfb77a79 Mon Sep 17 00:00:00 2001
From: Jia Xuan <1060996408+jiaxuan@users.noreply.github.com>
Date: Tue, 5 May 2026 09:27:41 +0800
Subject: [PATCH] fix(everything): remove dead code in template URI validation
 and subscription cleanup
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resources/templates.ts:
- `parseResourceId` had a guard that compared the URI against both
  `textUriBase` and `blobUriBase` with `&&`. Those prefixes are mutually
  exclusive, so the condition is always false and the branch is dead.
  Drop it; the SDK's template-based routing already guarantees the URI
  prefix is one of the two before the handler runs. The remaining
  positive-integer check on `resourceId` is preserved.

resources/subscriptions.ts:
- `sendSimulatedResourceUpdates` had an `else` branch that called
  `subscribers.delete(sessionId)` whenever the session wasn't in a URI's
  subscriber set, with a comment claiming the session had disconnected.
  That conclusion doesn't follow — a session not subscribed to URI A
  can still be subscribed to URI B — and the delete is a no-op when
  the element is absent anyway. Remove the branch.

No behavioral change. Existing 95 / 95 tests in `__tests__` still pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 src/everything/resources/subscriptions.ts |  9 ++----
 src/everything/resources/templates.ts     | 37 ++++++++++-------------
 2 files changed, 19 insertions(+), 27 deletions(-)

diff --git a/src/everything/resources/subscriptions.ts b/src/everything/resources/subscriptions.ts
index 2a5e57460f..854a8633a2 100644
--- a/src/everything/resources/subscriptions.ts
+++ b/src/everything/resources/subscriptions.ts
@@ -99,10 +99,9 @@ export const setSubscriptionHandlers = (server: McpServer) => {
 /**
  * Sends simulated resource update notifications to the subscribed client.
  *
- * This function iterates through all resource URIs stored in the subscriptions
- * and checks if the specified session ID is subscribed to them. If so, it sends
- * a notification through the provided server. If the session ID is no longer valid
- * (disconnected), it removes the session ID from the list of subscribers.
+ * Iterates the URIs in `subscriptions` and emits a
+ * `notifications/resources/updated` notification for each URI the given
+ * sessionId is subscribed to.
  *
  * @param {McpServer} server - The server instance used to send notifications.
  * @param {string | undefined} sessionId - The session ID of the client to check for subscriptions.
@@ -122,8 +121,6 @@ const sendSimulatedResourceUpdates = async (
         method: "notifications/resources/updated",
         params: { uri },
       });
-    } else {
-      subscribers.delete(sessionId); // subscriber has disconnected
     }
   }
 };
diff --git a/src/everything/resources/templates.ts b/src/everything/resources/templates.ts
index 6d4903f74c..4530741c54 100644
--- a/src/everything/resources/templates.ts
+++ b/src/everything/resources/templates.ts
@@ -127,31 +127,26 @@ export const blobResourceUri = (resourceId: number) =>
   new URL(`${blobUriBase}/${resourceId}`);
 
 /**
- * Parses the resource identifier from the provided URI and validates it
- * against the given variables. Throws an error if the URI corresponds
- * to an unknown resource or if the resource identifier is invalid.
+ * Parses the resource identifier from the provided variables and validates
+ * that it is a positive integer.
  *
- * @param {URL} uri - The URI of the resource to be parsed.
- * @param {Record<string, unknown>} variables - A record containing context-specific variables that include the resourceId.
- * @returns {number} The parsed and validated resource identifier as an integer.
- * @throws {Error} Throws an error if the URI matches unsupported base URIs or if the resourceId is invalid.
+ * The SDK only routes URIs that match the registered template to the
+ * resource handler, so by the time we get here the URI prefix is already
+ * known to be one of `textUriBase` / `blobUriBase`. Only the resourceId
+ * variable still needs validating.
+ *
+ * @param {URL} uri - The URI of the resource (used in the error message).
+ * @param {Record<string, unknown>} variables - Context variables including resourceId.
+ * @returns {number} The parsed and validated resource identifier as a positive integer.
+ * @throws {Error} If the resourceId is not a finite positive integer.
  */
 const parseResourceId = (uri: URL, variables: Record<string, unknown>) => {
-  const uriError = `Unknown resource: ${uri.toString()}`;
-  if (
-    uri.toString().startsWith(textUriBase) &&
-    uri.toString().startsWith(blobUriBase)
-  ) {
-    throw new Error(uriError);
-  } else {
-    const idxStr = String((variables as any).resourceId ?? "");
-    const idx = Number(idxStr);
-    if (Number.isFinite(idx) && Number.isInteger(idx) && idx > 0) {
-      return idx;
-    } else {
-      throw new Error(uriError);
-    }
+  const idxStr = String((variables as any).resourceId ?? "");
+  const idx = Number(idxStr);
+  if (Number.isFinite(idx) && Number.isInteger(idx) && idx > 0) {
+    return idx;
   }
+  throw new Error(`Unknown resource: ${uri.toString()}`);
 };
 
 /**