diff --git a/packages/coding-agent/CHANGELOG.md b/packages/coding-agent/CHANGELOG.md
index 02217349e..67a339e8a 100644
--- a/packages/coding-agent/CHANGELOG.md
+++ b/packages/coding-agent/CHANGELOG.md
@@ -184,6 +184,10 @@
 
 - Fixed the TUI `/usage` matrix mis-aligning multi-account columns across quota windows: each window row was sorted independently by used fraction, so the positional `account N` labels denoted different credentials per row and an exhausted limit (e.g. a Kimi Code account's 5h window) could render under a sibling that still had quota. Account columns are now ordered once per provider (worst-first) and held stable across every window row ([#6067](https://github.com/can1357/oh-my-pi/issues/6067)).
 
+### Fixed
+
+- Fixed near-miss `xd://` write targets silently creating filesystem paths instead of surfacing a corrective URI error ([#6123](https://github.com/can1357/oh-my-pi/issues/6123)).
+
 ## [17.0.5] - 2026-07-18
 
 ### Added
diff --git a/packages/coding-agent/src/tools/write.ts b/packages/coding-agent/src/tools/write.ts
index f1bb1bcd3..c1972faf0 100644
--- a/packages/coding-agent/src/tools/write.ts
+++ b/packages/coding-agent/src/tools/write.ts
@@ -85,6 +85,36 @@ import { renderXdevCall, renderXdevResult, type XdevDispatch } from "./xdev";
 
 const LOOSE_HASHLINE_HEADER_RE = /^\s*\[[^#\r\n]+#[^ \t\r\n]*\]\s*$/;
 const EXECUTABLE_NOTICE = "[Notice: Made executable via chmod +x]";
+const URI_LIKE_WRITE_PATH_RE = /^([a-z][a-z0-9+.-]*):\/{1,2}(.*)$/i;
+const XD_MISSING_DELIMITER_RE = /^xd\/+(.*)$/i;
+const XD_SCHEME_NEAR_MISSES: Record<string, true> = { dx: true, xdd: true, xdt: true };
+
+function assertWriteTargetAddressable(target: string, router: InternalUrlRouter): void {
+	const trimmed = target.trim();
+	if (path.win32.isAbsolute(trimmed) || router.canHandle(trimmed)) return;
+
+	const missingDelimiter = trimmed.match(XD_MISSING_DELIMITER_RE);
+	if (missingDelimiter) {
+		throw new ToolError(
+			`Unknown URI-like write target '${trimmed}'. Did you mean 'xd://${missingDelimiter[1]}'? Prefix the path with './' to write it as a filesystem path.`,
+		);
+	}
+
+	const uriLike = trimmed.match(URI_LIKE_WRITE_PATH_RE);
+	if (!uriLike) return;
+
+	const scheme = uriLike[1]!.toLowerCase();
+	// conflict:// has no router handler but is spliced downstream by
+	// parseConflictUri (which emits its own precise id/scope errors); let it pass.
+	if (scheme === "conflict") return;
+	const canonicalScheme = router.getHandler(scheme) ? scheme : XD_SCHEME_NEAR_MISSES[scheme] ? "xd" : undefined;
+	const suggestion = canonicalScheme
+		? ` Did you mean '${canonicalScheme}://${uriLike[2]}'?`
+		: " Tool devices use 'xd://<tool>'.";
+	throw new ToolError(
+		`Unknown URI-like write target '${trimmed}'.${suggestion} Prefix the path with './' to write it as a filesystem path.`,
+	);
+}
 
 const BULK_DIRECTIVE_RE = /^#?(\d+)\s*[:=]\s*(@ours|@theirs|@base|@both)$/;
 /**
@@ -987,6 +1017,7 @@ export class WriteTool implements AgentTool<typeof writeSchema, WriteToolDetails
 			// Strip hashline display prefixes ([PATH#HASH] + LINE:) if the model copied them from read output
 			const { text: cleanContent, stripped } = stripWriteContent(this.session, content);
 			const internalRouter = InternalUrlRouter.instance();
+			assertWriteTargetAddressable(path, internalRouter);
 			if (internalRouter.canHandle(path)) {
 				const parsed = parseInternalUrl(path);
 				const scheme = parsed.protocol.replace(/:$/, "").toLowerCase();
diff --git a/packages/coding-agent/test/write-xdev-dispatch.test.ts b/packages/coding-agent/test/write-xdev-dispatch.test.ts
index d8bf7190c..23f717cfd 100644
--- a/packages/coding-agent/test/write-xdev-dispatch.test.ts
+++ b/packages/coding-agent/test/write-xdev-dispatch.test.ts
@@ -86,6 +86,38 @@ describe("read and write route xd:// device URLs", () => {
 		}
 	});
 
+	it("rejects near-miss xd addresses before filesystem fallback", async () => {
+		const tempDir = await fs.mkdtemp(path.join(os.tmpdir(), "write-xdev-near-miss-"));
+		try {
+			const tools = await createTools(xdevSession(tempDir));
+			const write = tools.find(entry => entry.name === "write");
+			expect(write).toBeDefined();
+
+			for (const target of ["xdt://web_search", "xd:/web_search", "xd/web_search"]) {
+				await expect(write!.execute(`write-${target}`, { path: target, content: "{}" })).rejects.toThrow(
+					"Did you mean 'xd://web_search'?",
+				);
+			}
+			expect(await Bun.file(path.join(tempDir, "xdt:/web_search")).exists()).toBe(false);
+			expect(await Bun.file(path.join(tempDir, "xd/web_search")).exists()).toBe(false);
+
+			const escaped = await write!.execute("write-explicit-path", {
+				path: "./xd/web_search",
+				content: "intentional file",
+			});
+			expect(escaped.isError).toBeUndefined();
+			expect(await Bun.file(path.join(tempDir, "xd/web_search")).text()).toBe("intentional file");
+
+			// conflict:// has no router handler but is a documented write scheme —
+			// the guard must let it reach the conflict resolver, not reject it.
+			await expect(write!.execute("write-conflict", { path: "conflict://1", content: "x" })).rejects.toThrow(
+				"Conflict #1 not found",
+			);
+		} finally {
+			await removeWithRetries(tempDir);
+		}
+	});
+
 	it("resolves function-valued device approvals per payload and fails closed on bad content", async () => {
 		const tempDir = await fs.mkdtemp(path.join(os.tmpdir(), "write-xdev-approval-"));
 		try {