diff --git a/index.test.ts b/index.test.ts
index 7296aa0..c37a166 100644
--- a/index.test.ts
+++ b/index.test.ts
@@ -9,7 +9,7 @@ import {
 } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
-import { CompactClient } from "@morphllm/morphsdk";
+import { CompactClient, WarpGrepClient } from "@morphllm/morphsdk";
 
 // These are internal to the plugin but duplicated here for testing.
 const EXISTING_CODE_MARKER = "// ... existing code ...";
@@ -991,3 +991,69 @@ describe("ToolContext path resolution", () => {
     }
   });
 });
+
+describe("formatWarpGrepResult edge cases", () => {
+  async function executeSearch(fakeResult: unknown): Promise<string> {
+    const original = WarpGrepClient.prototype.execute;
+    WarpGrepClient.prototype.execute = function* () {
+      return fakeResult;
+    } as any;
+
+    try {
+      const { default: MorphPlugin } = await importPluginWithEnv({
+        MORPH_API_KEY: "sk-test-key",
+      });
+      const hooks = await MorphPlugin(makePluginInput("/tmp/morph-warpgrep-test"));
+      return (await hooks.tool.warpgrep_codebase_search.execute(
+        { search_term: "auth flow" },
+        makeToolContext("/tmp/morph-warpgrep-test"),
+      )) as string;
+    } finally {
+      WarpGrepClient.prototype.execute = original;
+    }
+  }
+
+  test("contexts with implausible file paths are rejected; valid paths from every OS render normally", async () => {
+    // Implausible: bare letters, empty strings, whitespace, no separators or extensions
+    for (const file of ["C", "", " ", "noextension"]) {
+      const result = await executeSearch({
+        success: true,
+        contexts: [{ file, content: "", lines: "*" }],
+      });
+      expect(result).toContain("malformed");
+      expect(result).not.toContain("<file path=");
+    }
+
+    // Valid paths across all major OS conventions
+    const validPaths = [
+      { file: "src/auth.ts", content: "code" },                         // unix relative
+      { file: "/usr/local/bin/server.js", content: "code" },            // unix absolute
+      { file: "C:\\Users\\dev\\project\\main.rs", content: "code" },    // windows absolute
+      { file: "packages\\core\\index.ts", content: "code" },            // windows relative
+      { file: "../sibling/lib.py", content: "code" },                   // relative with ..
+      { file: "./config.yaml", content: "code" },                       // relative with ./
+      { file: "Makefile.toml", content: "code" },                       // dot-extension only
+    ];
+
+    for (const ctx of validPaths) {
+      const result = await executeSearch({
+        success: true,
+        contexts: [{ ...ctx, lines: [[1, 5]] as Array<[number, number]> }],
+      });
+      expect(result).toContain("Relevant context found:");
+      expect(result).toContain(`<file path="${ctx.file}"`);
+    }
+  });
+
+  test("falsy error fields never surface literally; explicit errors pass through", async () => {
+    for (const error of [undefined, null, ""]) {
+      const result = await executeSearch({ success: false, error });
+      expect(result).toMatch(/^Search failed:/);
+      expect(result).not.toContain("undefined");
+      expect(result).not.toContain("null");
+    }
+
+    const result = await executeSearch({ success: false, error: "timeout after 60s" });
+    expect(result).toBe("Search failed: timeout after 60s");
+  });
+});
diff --git a/index.ts b/index.ts
index fc3b5b5..0190aa7 100644
--- a/index.ts
+++ b/index.ts
@@ -327,22 +327,41 @@ function buildMorphSystemRoutingHint(): string | null {
   return lines.length > 1 ? lines.join("\n") : null;
 }
 
+/**
+ * Minimal check for a plausible file path on any OS:
+ * - at least one path separator (/ or \) OR a dot-extension
+ * - not empty / whitespace-only
+ */
+const PLAUSIBLE_PATH_RE = /[/\\]|\.[\w]+$/;
+
+function isValidContext(ctx: { file: string; content: string }): boolean {
+  return Boolean(ctx.file) && PLAUSIBLE_PATH_RE.test(ctx.file) && ctx.content.length > 0;
+}
+
 /**
  * Format WarpGrep results for tool output
  */
 function formatWarpGrepResult(result: WarpGrepResult): string {
   if (!result.success) {
-    return `Search failed: ${result.error}`;
+    return `Search failed: ${result.error || "search returned no error details."}`;
   }
 
   if (!result.contexts || result.contexts.length === 0) {
     return "No relevant code found. Try rephrasing your search term.";
   }
 
+  const valid = result.contexts.filter(isValidContext);
+
+  if (valid.length === 0) {
+    const sample = result.contexts.slice(0, 3).map((c) => c.file);
+    return `Search returned malformed file contexts (file values: ${JSON.stringify(sample)}).
+Fallback: use \`grep\` + \`read\` for local code search.`;
+  }
+
   const parts: string[] = [];
   parts.push("Relevant context found:");
 
-  for (const ctx of result.contexts) {
+  for (const ctx of valid) {
     const rangeStr =
       !ctx.lines || ctx.lines === "*"
         ? "*"
@@ -352,7 +371,7 @@ function formatWarpGrepResult(result: WarpGrepResult): string {
 
   parts.push("\nFile contents:\n");
 
-  for (const ctx of result.contexts) {
+  for (const ctx of valid) {
     const rangeStr =
       !ctx.lines || ctx.lines === "*"
         ? ""
diff --git a/package.json b/package.json
index 021b426..de61246 100644
--- a/package.json
+++ b/package.json
@@ -21,7 +21,7 @@
     "ci": "bun test && bun run build && bun run typecheck"
   },
   "dependencies": {
-    "@morphllm/morphsdk": "^0.2.148",
+    "@morphllm/morphsdk": "0.2.160",
     "@opencode-ai/plugin": "latest",
     "@opencode-ai/sdk": "^1.2.22"
   },