From 6bf7417fcfcd477657da91da756bfe02217602f7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E2=80=9CSebastian?=
 <64795732+slegarraga@users.noreply.github.com>
Date: Thu, 6 Aug 2026 05:33:39 -0400
Subject: [PATCH] fix: avoid mcp030 critical from prose

---
 src/rules/helpers.ts | 10 ++++++++++
 src/rules/secrets.ts | 32 ++++++++++++++++++++++++++------
 test/rules.test.ts   | 41 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 77 insertions(+), 6 deletions(-)

diff --git a/src/rules/helpers.ts b/src/rules/helpers.ts
index ccb63a9..f1334e8 100644
--- a/src/rules/helpers.ts
+++ b/src/rules/helpers.ts
@@ -83,6 +83,16 @@ export const SECRET_PATH_PATTERNS = [
   ".kube/config",
 ];
 
+/** File patterns that are still strong signals when they appear in prose. */
+export const PROSE_SECRET_PATH_PATTERNS = [
+  ".env",
+  "id_rsa",
+  "id_ed25519",
+  "/etc/passwd",
+  "/etc/shadow",
+  ".pem",
+];
+
 /** Case-insensitive "does haystack contain any needle". */
 export function containsAny(
   haystack: string | undefined,
diff --git a/src/rules/secrets.ts b/src/rules/secrets.ts
index ed7b2f4..8731d31 100644
--- a/src/rules/secrets.ts
+++ b/src/rules/secrets.ts
@@ -1,5 +1,9 @@
 import type { Finding, Rule } from "../types.js";
-import { containsAny, SECRET_PATH_PATTERNS } from "./helpers.js";
+import {
+  containsAny,
+  PROSE_SECRET_PATH_PATTERNS,
+  SECRET_PATH_PATTERNS,
+} from "./helpers.js";
 
 const PATH_ARG_NAMES = ["path", "file", "filename", "filepath", "dir", "directory", "location"];
 
@@ -12,25 +16,41 @@ export const resourceExposesSecrets: Rule = {
   id: "MCP030",
   title: "Resource exposes secrets or sensitive paths",
   description:
-    "Resources should never surface credential files, private keys, or sensitive system paths.",
+    "Resources should never surface credential files, private keys, or sensitive system paths. URI evidence is critical; metadata prose is reported at high only for unambiguous file patterns.",
   severity: "critical",
   category: "secrets",
   evaluate(target, ctx): Finding[] {
     const findings: Finding[] = [];
     for (const res of target.resources) {
-      const haystack = `${res.uri} ${res.name ?? ""} ${res.description ?? ""}`;
-      const hit = containsAny(haystack, SECRET_PATH_PATTERNS);
-      if (hit) {
+      const uriHit = containsAny(res.uri, SECRET_PATH_PATTERNS);
+      if (uriHit) {
         findings.push(
           ctx.report({
             title: "Resource surfaces sensitive material",
-            message: `Resource "${res.uri}" references "${hit}", which commonly holds secrets or system credentials.`,
+            message: `Resource "${res.uri}" references "${uriHit}", which commonly holds secrets or system credentials.`,
             remediation:
               "Remove the resource or restrict it to non-sensitive content. Never expose credential files or system paths over MCP.",
             location: res.uri,
           }),
         );
       }
+
+      const proseHit = containsAny(
+        `${res.name ?? ""} ${res.description ?? ""}`,
+        PROSE_SECRET_PATH_PATTERNS,
+      );
+      if (proseHit) {
+        findings.push(
+          ctx.report({
+            title: "Resource metadata references sensitive material",
+            message: `Resource "${res.uri}" metadata references "${proseHit}", which is an unambiguous sensitive file pattern.`,
+            remediation:
+              "Review the resource name and description. Only a resource that actually exposes the file should be removed or restricted.",
+            location: res.uri,
+            severity: "high",
+          }),
+        );
+      }
     }
     return findings;
   },
diff --git a/test/rules.test.ts b/test/rules.test.ts
index 7f1cde8..c79c572 100644
--- a/test/rules.test.ts
+++ b/test/rules.test.ts
@@ -102,6 +102,47 @@ describe("MCP040 http auth", () => {
   });
 });
 
+describe("MCP030 resource secrets", () => {
+  it("does not flag generic credentials wording in a description", () => {
+    const target = makeTarget({
+      resources: [
+        {
+          uri: "https://example.com/notes",
+          name: "Project notes",
+          description: "Project notes. Contains no credentials or secrets.",
+        },
+      ],
+    });
+    const findings = audit(target).findings.filter(
+      (f) => f.ruleId === "MCP030",
+    );
+    expect(findings).toHaveLength(0);
+  });
+
+  it("reports URI evidence as critical and prose evidence as high", () => {
+    const target = makeTarget({
+      resources: [
+        {
+          uri: "file:///home/me/.env",
+          name: "Environment backup",
+          description: "Local environment backup",
+        },
+        {
+          uri: "https://example.com/resource",
+          name: "server.pem",
+          description: "TLS certificate material",
+        },
+      ],
+    });
+    const findings = audit(target).findings.filter(
+      (f) => f.ruleId === "MCP030",
+    );
+    expect(findings).toHaveLength(2);
+    expect(findings.some((f) => f.severity === "critical")).toBe(true);
+    expect(findings.some((f) => f.severity === "high")).toBe(true);
+  });
+});
+
 describe("MCP060 tool name collision", () => {
   it("detects duplicate tool names", () => {
     const target = makeTarget({