From 14f5456ef043d15709db4dcbfdbbf5eb58e256d6 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Tue, 26 Aug 2025 14:12:39 +0900
Subject: [PATCH 01/20] =?UTF-8?q?feat(misskey-js):=20acct.parse=E3=81=8CUR?=
 =?UTF-8?q?L=E3=82=92=E5=8F=97=E3=81=91=E4=BB=98=E3=81=91=E3=82=8B?=
 =?UTF-8?q?=E3=82=88=E3=81=86=E3=81=AB,=20acct.ts=E3=81=AE=E3=83=86?=
 =?UTF-8?q?=E3=82=B9=E3=83=88=E3=82=92=E8=BF=BD=E5=8A=A0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 packages/misskey-js/src/acct.ts  | 49 ++++++++++++++++++---
 packages/misskey-js/test/acct.ts | 75 ++++++++++++++++++++++++++++++++
 2 files changed, 119 insertions(+), 5 deletions(-)
 create mode 100644 packages/misskey-js/test/acct.ts

diff --git a/packages/misskey-js/src/acct.ts b/packages/misskey-js/src/acct.ts
index aa8658cdbd..8d73d3ea09 100644
--- a/packages/misskey-js/src/acct.ts
+++ b/packages/misskey-js/src/acct.ts
@@ -3,11 +3,50 @@ export type Acct = {
 	host: string | null;
 };
 
-export function parse(_acct: string): Acct {
-	let acct = _acct;
-	if (acct.startsWith('@')) acct = acct.substring(1);
-	const split = acct.split('@', 2);
-	return { username: split[0], host: split[1] || null };
+/**
+ * Parses a string and returns an Acct object.
+ * @param acct String to parse
+ *   The string should be in one of the following formats:
+ *   * At-mark style: `@username@example.com`
+ *   * Starts with `acct:`: `acct:username@example.com`
+ *   * URL style: `https://example.com/@username`, `https://self.example.com/@username@other.example.com`
+ * @param localHostname If provided and matches the host found in acct, the returned `host` will be set to `null`.
+ * @returns Acct object
+ */
+export function parse(acct: string, localHostname?: string): Acct {
+	//#region url style
+	if (acct.startsWith('https://') || acct.startsWith('http://')) {
+		const url = new URL(acct);
+		const path = url.pathname.split('/').find((p) => p.startsWith('@') && p.length >= 2);
+		if (!path) throw new Error('This url is not acct like.');
+
+		const split = path.split('@', 3); // ['', 'username', 'other.example.com']
+
+		let host: string | null = split[2] || url.hostname;
+		if (localHostname && host === localHostname) {
+			host = null;
+		}
+
+		return { username: split[1], host: host };
+	}
+	//#endregion
+
+	//#region at-mark and acct: style
+	let acctWithNoPrefix = acct;
+	if (acct.startsWith('@')) {
+		acctWithNoPrefix = acct.substring(1);
+	} else if (acct.startsWith('acct:')) {
+		acctWithNoPrefix = acct.substring(5);
+	}
+	const split = acctWithNoPrefix.split('@', 2);
+
+	let host: string | null = split[1] || null;
+	if (localHostname && host === localHostname) {
+		host = null;
+	}
+
+	return { username: split[0], host };
+	//#endregion
 }
 
 export function toString(acct: Acct): string {
diff --git a/packages/misskey-js/test/acct.ts b/packages/misskey-js/test/acct.ts
new file mode 100644
index 0000000000..7727565480
--- /dev/null
+++ b/packages/misskey-js/test/acct.ts
@@ -0,0 +1,75 @@
+import { describe, it, expect } from 'vitest';
+import * as acct from '../src/acct.js';
+
+describe('acct.parse', () => {
+	it('parses plain username', () => {
+		const res = acct.parse('alice');
+		expect(res).toEqual({ username: 'alice', host: null });
+	});
+
+	it('parses at-mark style without host', () => {
+		const res = acct.parse('@alice');
+		expect(res).toEqual({ username: 'alice', host: null });
+	});
+
+	it('parses at-mark style with host', () => {
+		const res = acct.parse('@alice@example.com');
+		expect(res).toEqual({ username: 'alice', host: 'example.com' });
+	});
+
+	it('nulls host for at-mark style when localHostname matches', () => {
+		const res = acct.parse('@alice@example.com', 'example.com');
+		expect(res).toEqual({ username: 'alice', host: null });
+	});
+
+	it('parses acct: style', () => {
+		const res = acct.parse('acct:alice@example.com');
+		expect(res).toEqual({ username: 'alice', host: 'example.com' });
+	});
+
+	it('nulls host for acct: style when localHostname matches', () => {
+		const res = acct.parse('acct:alice@example.com', 'example.com');
+		expect(res).toEqual({ username: 'alice', host: null });
+	});
+
+	it('parses url style https with same host -> host kept when localHostname not provided', () => {
+		const res = acct.parse('https://example.com/@alice');
+		expect(res).toEqual({ username: 'alice', host: 'example.com' });
+	});
+
+	it('parses url style http with same host and nulls host when localHostname matches', () => {
+		const res = acct.parse('http://example.com/@alice', 'example.com');
+		expect(res).toEqual({ username: 'alice', host: null });
+	});
+
+	it('parses url style with remote host contained in path', () => {
+		const res = acct.parse('https://self.example.com/@alice@other.example.com');
+		expect(res).toEqual({ username: 'alice', host: 'other.example.com' });
+	});
+
+	it('nulls host when localHostname matches the remote host in path', () => {
+		const res = acct.parse('https://self.example.com/@alice@other.example.com', 'other.example.com');
+		expect(res).toEqual({ username: 'alice', host: null });
+	});
+
+	it('throws on non-acct-like url path', () => {
+		expect(() => acct.parse('https://example.com/users/alice')).toThrowError();
+	});
+
+	it('parses correctly Mr.http', () => {
+		const res = acct.parse('http');
+		expect(res).toEqual({ username: 'http', host: null });
+	});
+});
+
+describe('acct.toString', () => {
+	it('returns username when host is null', () => {
+		expect(acct.toString({ username: 'alice', host: null })).toBe('alice');
+	});
+
+	it('returns username@host when host exists', () => {
+		expect(acct.toString({ username: 'alice', host: 'example.com' })).toBe('alice@example.com');
+	});
+});
+
+

From a8eff662e326d13861dd22cf5c04d1b4a9179eab Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Tue, 26 Aug 2025 14:28:43 +0900
Subject: [PATCH 02/20] =?UTF-8?q?feat(misskey-js):=20acct.parse=E3=81=8CUR?=
 =?UTF-8?q?L=E3=82=92=E5=8F=97=E3=81=91=E4=BB=98=E3=81=91=E3=82=8B?=
 =?UTF-8?q?=E3=82=88=E3=81=86=E3=81=AB,=20acct.ts=E3=81=AE=E3=83=86?=
 =?UTF-8?q?=E3=82=B9=E3=83=88=E3=82=92=E8=BF=BD=E5=8A=A0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 packages/misskey-js/src/acct.ts | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/packages/misskey-js/src/acct.ts b/packages/misskey-js/src/acct.ts
index 8d73d3ea09..392c5ca947 100644
--- a/packages/misskey-js/src/acct.ts
+++ b/packages/misskey-js/src/acct.ts
@@ -3,6 +3,16 @@ export type Acct = {
 	host: string | null;
 };
 
+export function correctAcct(acct: Acct, localHostname?: string): Acct {
+	const result = { ...acct };
+	if (!acct.host) {
+		result.host = null;
+	} else if (localHostname && acct.host === localHostname) {
+		result.host = null;
+	}
+	return result;
+}
+
 /**
  * Parses a string and returns an Acct object.
  * @param acct String to parse
@@ -22,12 +32,7 @@ export function parse(acct: string, localHostname?: string): Acct {
 
 		const split = path.split('@', 3); // ['', 'username', 'other.example.com']
 
-		let host: string | null = split[2] || url.hostname;
-		if (localHostname && host === localHostname) {
-			host = null;
-		}
-
-		return { username: split[1], host: host };
+		return correctAcct({ username: split[1], host: split[2] || url.hostname }, localHostname);
 	}
 	//#endregion
 
@@ -40,12 +45,7 @@ export function parse(acct: string, localHostname?: string): Acct {
 	}
 	const split = acctWithNoPrefix.split('@', 2);
 
-	let host: string | null = split[1] || null;
-	if (localHostname && host === localHostname) {
-		host = null;
-	}
-
-	return { username: split[0], host };
+	return correctAcct({ username: split[0], host: split[1] || null }, localHostname);
 	//#endregion
 }
 

From 0dbaa6f2ae1cf0c01b78c30801aaad4c28ea3e5c Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Tue, 26 Aug 2025 14:39:33 +0900
Subject: [PATCH 03/20] api

---
 packages/misskey-js/etc/misskey-js.api.md | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/misskey-js/etc/misskey-js.api.md b/packages/misskey-js/etc/misskey-js.api.md
index 170c20f163..ef4f3ae8c2 100644
--- a/packages/misskey-js/etc/misskey-js.api.md
+++ b/packages/misskey-js/etc/misskey-js.api.md
@@ -23,6 +23,7 @@ export type Acct = {
 
 declare namespace acct {
     export {
+        correctAcct,
         parse,
         toString_2 as toString,
         Acct
@@ -1229,6 +1230,9 @@ type ClipsUpdateRequest = operations['clips___update']['requestBody']['content']
 // @public (undocumented)
 type ClipsUpdateResponse = operations['clips___update']['responses']['200']['content']['application/json'];
 
+// @public (undocumented)
+function correctAcct(acct: Acct, localHostname?: string): Acct;
+
 // @public (undocumented)
 type DateString = string;
 
@@ -3253,7 +3257,7 @@ type PagesUnlikeRequest = operations['pages___unlike']['requestBody']['content']
 type PagesUpdateRequest = operations['pages___update']['requestBody']['content']['application/json'];
 
 // @public (undocumented)
-function parse(_acct: string): Acct;
+function parse(acct: string, localHostname?: string): Acct;
 
 // Warning: (ae-forgotten-export) The symbol "Values" needs to be exported by the entry point index.d.ts
 //

From c7902feb49e39848c476a399d745f8dccddbfc64 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Tue, 26 Aug 2025 14:46:50 +0900
Subject: [PATCH 04/20] clean up

---
 packages/misskey-js/test/acct.ts | 2 --
 1 file changed, 2 deletions(-)

diff --git a/packages/misskey-js/test/acct.ts b/packages/misskey-js/test/acct.ts
index 7727565480..e0ebc0551b 100644
--- a/packages/misskey-js/test/acct.ts
+++ b/packages/misskey-js/test/acct.ts
@@ -71,5 +71,3 @@ describe('acct.toString', () => {
 		expect(acct.toString({ username: 'alice', host: 'example.com' })).toBe('alice@example.com');
 	});
 });
-
-

From 71783d8f063ee1216bf666d743fbd842e4a92da4 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Tue, 26 Aug 2025 21:51:17 +0900
Subject: [PATCH 05/20] iikanji

---
 packages/misskey-js/src/acct.ts  | 50 +++++++++++--------
 packages/misskey-js/test/acct.ts | 86 ++++++++++++++++++++++----------
 2 files changed, 88 insertions(+), 48 deletions(-)

diff --git a/packages/misskey-js/src/acct.ts b/packages/misskey-js/src/acct.ts
index 392c5ca947..74e0ff06f0 100644
--- a/packages/misskey-js/src/acct.ts
+++ b/packages/misskey-js/src/acct.ts
@@ -13,6 +13,30 @@ export function correctAcct(acct: Acct, localHostname?: string): Acct {
 	return result;
 }
 
+export function parse(acct: string): Acct {
+	let acctWithNoPrefix = acct;
+
+	if (acct.startsWith('@')) {
+		acctWithNoPrefix = acct.substring(1);
+	} else if (acct.startsWith('acct:')) {
+		acctWithNoPrefix = acct.substring(5);
+	}
+
+	const split = acctWithNoPrefix.split('@', 2);
+
+	return { username: split[0], host: split[1] || null };
+}
+
+export function parseUrl(str: string): Acct {
+	const url = new URL(str);
+	const path = url.pathname.split('/').find((p) => p.startsWith('@') && p.length >= 2);
+	if (!path) throw new Error('This url is not acct like.');
+
+	const split = path.split('@', 3); // ['', 'username', 'other.example.com']
+
+	return { username: split[1], host: split[2] || url.hostname };
+}
+
 /**
  * Parses a string and returns an Acct object.
  * @param acct String to parse
@@ -23,30 +47,14 @@ export function correctAcct(acct: Acct, localHostname?: string): Acct {
  * @param localHostname If provided and matches the host found in acct, the returned `host` will be set to `null`.
  * @returns Acct object
  */
-export function parse(acct: string, localHostname?: string): Acct {
-	//#region url style
+export function parseAcctOrUrl(acct: string, localHostname?: string): Acct {
 	if (acct.startsWith('https://') || acct.startsWith('http://')) {
-		const url = new URL(acct);
-		const path = url.pathname.split('/').find((p) => p.startsWith('@') && p.length >= 2);
-		if (!path) throw new Error('This url is not acct like.');
-
-		const split = path.split('@', 3); // ['', 'username', 'other.example.com']
-
-		return correctAcct({ username: split[1], host: split[2] || url.hostname }, localHostname);
+		// url style
+		return correctAcct(parseUrl(acct), localHostname);
 	}
-	//#endregion
 
-	//#region at-mark and acct: style
-	let acctWithNoPrefix = acct;
-	if (acct.startsWith('@')) {
-		acctWithNoPrefix = acct.substring(1);
-	} else if (acct.startsWith('acct:')) {
-		acctWithNoPrefix = acct.substring(5);
-	}
-	const split = acctWithNoPrefix.split('@', 2);
-
-	return correctAcct({ username: split[0], host: split[1] || null }, localHostname);
-	//#endregion
+	// acct style
+	return correctAcct(parse(acct), localHostname);
 }
 
 export function toString(acct: Acct): string {
diff --git a/packages/misskey-js/test/acct.ts b/packages/misskey-js/test/acct.ts
index e0ebc0551b..fd59a82c9d 100644
--- a/packages/misskey-js/test/acct.ts
+++ b/packages/misskey-js/test/acct.ts
@@ -1,64 +1,96 @@
 import { describe, it, expect } from 'vitest';
 import * as acct from '../src/acct.js';
 
-describe('acct.parse', () => {
+function testParseAcct(fn: (acct: string) => acct.Acct) {
 	it('parses plain username', () => {
-		const res = acct.parse('alice');
+		const res = fn('alice');
 		expect(res).toEqual({ username: 'alice', host: null });
 	});
 
 	it('parses at-mark style without host', () => {
-		const res = acct.parse('@alice');
+		const res = fn('@alice');
 		expect(res).toEqual({ username: 'alice', host: null });
 	});
 
 	it('parses at-mark style with host', () => {
-		const res = acct.parse('@alice@example.com');
+		const res = fn('@alice@example.com');
 		expect(res).toEqual({ username: 'alice', host: 'example.com' });
 	});
 
-	it('nulls host for at-mark style when localHostname matches', () => {
-		const res = acct.parse('@alice@example.com', 'example.com');
-		expect(res).toEqual({ username: 'alice', host: null });
-	});
-
 	it('parses acct: style', () => {
-		const res = acct.parse('acct:alice@example.com');
+		const res = fn('acct:alice@example.com');
 		expect(res).toEqual({ username: 'alice', host: 'example.com' });
 	});
 
-	it('nulls host for acct: style when localHostname matches', () => {
-		const res = acct.parse('acct:alice@example.com', 'example.com');
-		expect(res).toEqual({ username: 'alice', host: null });
+	it('parse Mr.http', () => {
+		const res = fn('http');
+		expect(res).toEqual({ username: 'http', host: null });
 	});
+}
 
+function testParseUrl(fn: (acct: string) => acct.Acct) {
 	it('parses url style https with same host -> host kept when localHostname not provided', () => {
-		const res = acct.parse('https://example.com/@alice');
+		const res = fn('https://example.com/@alice');
 		expect(res).toEqual({ username: 'alice', host: 'example.com' });
 	});
 
-	it('parses url style http with same host and nulls host when localHostname matches', () => {
-		const res = acct.parse('http://example.com/@alice', 'example.com');
-		expect(res).toEqual({ username: 'alice', host: null });
-	});
-
 	it('parses url style with remote host contained in path', () => {
-		const res = acct.parse('https://self.example.com/@alice@other.example.com');
+		const res = fn('https://self.example.com/@alice@other.example.com');
 		expect(res).toEqual({ username: 'alice', host: 'other.example.com' });
 	});
 
-	it('nulls host when localHostname matches the remote host in path', () => {
-		const res = acct.parse('https://self.example.com/@alice@other.example.com', 'other.example.com');
+	it('throws on non-acct-like url path', () => {
+		expect(() => fn('https://example.com/users/alice')).toThrowError();
+	});
+}
+
+describe('acct.parse', () => {
+	testParseAcct(acct.parse);
+});
+
+describe('acct.parseUrl', () => {
+	testParseUrl(acct.parseUrl);
+});
+
+describe('acct.parseAcctOrUrl', () => {
+	testParseAcct(acct.parseAcctOrUrl);
+	testParseUrl(acct.parseAcctOrUrl);
+
+	it('parse url with localHostname', () => {
+		const res = acct.parseAcctOrUrl('https://example.com/@alice', 'example.com');
 		expect(res).toEqual({ username: 'alice', host: null });
 	});
 
-	it('throws on non-acct-like url path', () => {
-		expect(() => acct.parse('https://example.com/users/alice')).toThrowError();
+	it('parse @username with localHostname', () => {
+		const res = acct.parseAcctOrUrl('@alice', 'example.com');
+		expect(res).toEqual({ username: 'alice', host: null });
+	});
+});
+
+describe('acct.correctAcct', () => {
+	it('returns host=null when acct.host is null', () => {
+		const input: acct.Acct = { username: 'alice', host: null };
+		const out = acct.correctAcct(input);
+		expect(out).toEqual({ username: 'alice', host: null });
+		expect(out).not.toBe(input); // immutability
 	});
 
-	it('parses correctly Mr.http', () => {
-		const res = acct.parse('http');
-		expect(res).toEqual({ username: 'http', host: null });
+	it('keeps host when localHostname not provided', () => {
+		const input: acct.Acct = { username: 'bob', host: 'example.com' };
+		const out = acct.correctAcct(input);
+		expect(out).toEqual({ username: 'bob', host: 'example.com' });
+	});
+
+	it('nulls host when it matches localHostname', () => {
+		const input: acct.Acct = { username: 'carol', host: 'example.com' };
+		const out = acct.correctAcct(input, 'example.com');
+		expect(out).toEqual({ username: 'carol', host: null });
+	});
+
+	it('keeps host when it differs from localHostname', () => {
+		const input: acct.Acct = { username: 'dave', host: 'other.example.com' };
+		const out = acct.correctAcct(input, 'example.com');
+		expect(out).toEqual({ username: 'dave', host: 'other.example.com' });
 	});
 });
 

From 22e8fa4cba1139bd8f8ffbc8ba93595c87dc8804 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Tue, 26 Aug 2025 22:02:21 +0900
Subject: [PATCH 06/20] api

---
 packages/misskey-js/etc/misskey-js.api.md | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/packages/misskey-js/etc/misskey-js.api.md b/packages/misskey-js/etc/misskey-js.api.md
index ef4f3ae8c2..cd2ca0db32 100644
--- a/packages/misskey-js/etc/misskey-js.api.md
+++ b/packages/misskey-js/etc/misskey-js.api.md
@@ -25,6 +25,8 @@ declare namespace acct {
     export {
         correctAcct,
         parse,
+        parseUrl,
+        parseAcctOrUrl,
         toString_2 as toString,
         Acct
     }
@@ -3257,7 +3259,13 @@ type PagesUnlikeRequest = operations['pages___unlike']['requestBody']['content']
 type PagesUpdateRequest = operations['pages___update']['requestBody']['content']['application/json'];
 
 // @public (undocumented)
-function parse(acct: string, localHostname?: string): Acct;
+function parse(acct: string): Acct;
+
+// @public (undocumented)
+function parseAcctOrUrl(acct: string, localHostname?: string): Acct;
+
+// @public (undocumented)
+function parseUrl(str: string): Acct;
 
 // Warning: (ae-forgotten-export) The symbol "Values" needs to be exported by the entry point index.d.ts
 //

From 3bf39a5c99d9eab087632b2d0395c59ed969c5a2 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Thu, 28 Aug 2025 10:38:41 +0900
Subject: [PATCH 07/20] build-misskey-js-with-types

---
 packages/misskey-js/src/autogen/types.ts | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/packages/misskey-js/src/autogen/types.ts b/packages/misskey-js/src/autogen/types.ts
index be24e3ec5f..908a9289f3 100644
--- a/packages/misskey-js/src/autogen/types.ts
+++ b/packages/misskey-js/src/autogen/types.ts
@@ -9329,8 +9329,10 @@ export interface operations {
                         mcaptchaSecretKey: string | null;
                         recaptchaSecretKey: string | null;
                         turnstileSecretKey: string | null;
-                        sensitiveMediaDetection: string;
-                        sensitiveMediaDetectionSensitivity: string;
+                        /** @enum {string} */
+                        sensitiveMediaDetection: 'none' | 'all' | 'local' | 'remote';
+                        /** @enum {string} */
+                        sensitiveMediaDetectionSensitivity: 'medium' | 'low' | 'high' | 'veryLow' | 'veryHigh';
                         setSensitiveFlagAutomatically: boolean;
                         enableSensitiveMediaDetectionForVideos: boolean;
                         /** Format: id */

From b1d8a092e56c9cbbbc30fb25cd38e3448268ac00 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Thu, 28 Aug 2025 11:42:43 +0900
Subject: [PATCH 08/20] wip

---
 .../src/server/api/endpoints/ap/show.ts       | 57 +++++++++++++++++--
 1 file changed, 53 insertions(+), 4 deletions(-)

diff --git a/packages/backend/src/server/api/endpoints/ap/show.ts b/packages/backend/src/server/api/endpoints/ap/show.ts
index 4afed7dc5c..a7e6aa5b3f 100644
--- a/packages/backend/src/server/api/endpoints/ap/show.ts
+++ b/packages/backend/src/server/api/endpoints/ap/show.ts
@@ -5,6 +5,7 @@
 
 import { Inject, Injectable } from '@nestjs/common';
 import ms from 'ms';
+import * as misskey from 'misskey-js';
 import { Endpoint } from '@/server/api/endpoint-base.js';
 import type { MiNote } from '@/models/Note.js';
 import type { MiLocalUser, MiUser } from '@/models/User.js';
@@ -21,6 +22,9 @@ import { bindThis } from '@/decorators.js';
 import { ApiError } from '../../error.js';
 import { IdentifiableError } from '@/misc/identifiable-error.js';
 import { FetchAllowSoftFailMask } from '@/core/activitypub/misc/check-against-url.js';
+import { RemoteUserResolveService } from '@/core/RemoteUserResolveService.js';
+import { DI } from '@/di-symbols.js';
+import type { MiMeta } from '@/models/_.js';
 
 export const meta = {
 	tags: ['federation'],
@@ -59,6 +63,11 @@ export const meta = {
 			code: 'NO_SUCH_OBJECT',
 			id: 'dc94d745-1262-4e63-a17d-fecaa57efc82',
 		},
+		somethingHappenedInFetchingUri: {
+			message: 'Something happened while fetching the URI.',
+			code: 'SOMETHING_HAPPENED_IN_FETCHING_URI',
+			id: '14d45054-9df7-4f85-9e60-343b22f16b05,
+		},
 	},
 
 	res: {
@@ -102,6 +111,7 @@ export const paramDef = {
 	type: 'object',
 	properties: {
 		uri: { type: 'string' },
+		onlyUriFetch: { type: 'boolean', optional: true, nullable: false },
 	},
 	required: ['uri'],
 } as const;
@@ -109,6 +119,9 @@ export const paramDef = {
 @Injectable()
 export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-disable-line import/no-default-export
 	constructor(
+		@Inject(DI.meta)
+		private serverSettings: MiMeta,
+
 		private utilityService: UtilityService,
 		private userEntityService: UserEntityService,
 		private noteEntityService: NoteEntityService,
@@ -116,9 +129,31 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 		private apDbResolverService: ApDbResolverService,
 		private apPersonService: ApPersonService,
 		private apNoteService: ApNoteService,
+		private remoteUserResolveService: RemoteUserResolveService,
 	) {
 		super(meta, paramDef, async (ps, me) => {
-			const object = await this.fetchAny(ps.uri, me);
+			let object: SchemaType<typeof meta['res']> | null;
+
+			if (!ps.onlyUriFetch) {
+				try {
+					object = await this.fetchAcct(misskey.acct.parseAcctOrUrl(ps.uri), me);
+				} catch (err) {
+					if (err instanceof IdentifiableError && err.id === 'bddd9f4c-f0a8-4cac-9c0a-4e6d2fc43408') {
+						// Signin required
+						throw new ApiError(meta.errors.noSuchObject);
+					}
+				}
+			}
+
+			try {
+				object = await this.fetchAnyUri(ps.uri, me);
+			} catch (err) {
+				if (err instanceof ApiError) {
+					throw err;
+				}
+				throw new ApiError(meta.errors.somethingHappenedInFetchingUri);
+			}
+
 			if (object) {
 				return object;
 			} else {
@@ -127,11 +162,26 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 		});
 	}
 
-	/***
+	private async fetchAcct(acct: misskey.acct.Acct, me: MiLocalUser | null | undefined): Promise<SchemaType<typeof meta['res']> | null> {
+		if (this.serverSettings.ugcVisibilityForVisitor === 'local' && me == null) {
+			throw new IdentifiableError('bddd9f4c-f0a8-4cac-9c0a-4e6d2fc43408', 'Signin required');
+		}
+
+		const user = await this.remoteUserResolveService.resolveUser(acct.username, acct.host);
+
+		if (!user) return null;
+
+		return {
+			type: 'User',
+			object: await this.userEntityService.pack(user, me, { schema: 'UserDetailed' }),
+		}
+	}
+
+	/**
 	 * URIからUserかNoteを解決する
 	 */
 	@bindThis
-	private async fetchAny(uri: string, me: MiLocalUser | null | undefined): Promise<SchemaType<typeof meta['res']> | null> {
+	private async fetchAnyUri(uri: string, me: MiLocalUser | null | undefined): Promise<SchemaType<typeof meta['res']> | null> {
 		if (!this.utilityService.isFederationAllowedUri(uri)) {
 			throw new ApiError(meta.errors.federationNotAllowed);
 		}
@@ -174,7 +224,6 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 						throw new ApiError(meta.errors.responseInvalid);
 				}
 			}
-
 			throw new ApiError(meta.errors.requestFailed);
 		});
 

From 70e57ccf32000f1a5b3f4241f6a8136fdeeab3e4 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Thu, 28 Aug 2025 22:12:33 +0900
Subject: [PATCH 09/20] wip

---
 .../src/server/api/endpoints/ap/show.ts       |  2 +-
 .../test-federation/test/api/ap/show.test.ts  | 66 +++++++++++++++++++
 2 files changed, 67 insertions(+), 1 deletion(-)
 create mode 100644 packages/backend/test-federation/test/api/ap/show.test.ts

diff --git a/packages/backend/src/server/api/endpoints/ap/show.ts b/packages/backend/src/server/api/endpoints/ap/show.ts
index a7e6aa5b3f..f62baf79e1 100644
--- a/packages/backend/src/server/api/endpoints/ap/show.ts
+++ b/packages/backend/src/server/api/endpoints/ap/show.ts
@@ -66,7 +66,7 @@ export const meta = {
 		somethingHappenedInFetchingUri: {
 			message: 'Something happened while fetching the URI.',
 			code: 'SOMETHING_HAPPENED_IN_FETCHING_URI',
-			id: '14d45054-9df7-4f85-9e60-343b22f16b05,
+			id: '14d45054-9df7-4f85-9e60-343b22f16b05',
 		},
 	},
 
diff --git a/packages/backend/test-federation/test/api/ap/show.test.ts b/packages/backend/test-federation/test/api/ap/show.test.ts
new file mode 100644
index 0000000000..7c35026269
--- /dev/null
+++ b/packages/backend/test-federation/test/api/ap/show.test.ts
@@ -0,0 +1,66 @@
+import { strictEqual, rejects } from 'node:assert';
+import * as Misskey from 'misskey-js';
+import { createAccount, resolveRemoteUser, sleep, type LoginUser } from '../../utils.js';
+
+describe('API ap/show', () => {
+  let alice: LoginUser, bob: LoginUser;
+  let bobInA: Misskey.entities.UserDetailedNotMe;
+
+  beforeAll(async () => {
+    [alice, bob] = await Promise.all([
+      createAccount('a.test'),
+      createAccount('b.test'),
+    ]);
+
+    // 事前に bob を a.test に解決してキャッシュ・同一性を取る
+    bobInA = await resolveRemoteUser('b.test', bob.id, alice);
+  });
+
+  describe('User resolution', () => {
+    test('resolve by acct (bob@b.test)', async () => {
+      const res = await alice.client.request('ap/show', { uri: `${bob.username}@b.test` });
+      strictEqual(res.type, 'User');
+      strictEqual(res.object.id, bobInA.id);
+      strictEqual(res.object.uri, `https://b.test/users/${bob.id}`);
+    });
+
+    test('resolve by canonical user URL (https://b.test/users/:id)', async () => {
+      const res = await alice.client.request('ap/show', { uri: `https://b.test/users/${bob.id}` });
+      strictEqual(res.type, 'User');
+      strictEqual(res.object.id, bobInA.id);
+      strictEqual(res.object.uri, `https://b.test/users/${bob.id}`);
+    });
+
+    test('resolve by cross-origin non-canonical URL (https://a.test/@bob@b.test)', async () => {
+      const res = await alice.client.request('ap/show', { uri: `https://a.test/@${bob.username}@b.test` });
+      strictEqual(res.type, 'User');
+      // 非正規URLから正規IDに追従して同一ユーザーになること
+      strictEqual(res.object.id, bobInA.id);
+      strictEqual(res.object.uri, `https://b.test/users/${bob.id}`);
+    });
+
+    test('onlyUriFetch=true with acct string should fail with URI_INVALID', async () => {
+      await rejects(
+        async () => await alice.client.request('ap/show', { uri: `${bob.username}@b.test`, onlyUriFetch: true }),
+        (err: any) => {
+          strictEqual(err.code, 'URI_INVALID');
+          return true;
+        },
+      );
+    });
+  });
+
+  describe('Note resolution', () => {
+    test('resolve by note URL (https://b.test/notes/:id)', async () => {
+      const note = (await bob.client.request('notes/create', { text: 'hello from Bob' })).createdNote;
+      // 伝搬待ち
+      await sleep();
+
+      const res = await alice.client.request('ap/show', { uri: `https://b.test/notes/${note.id}` });
+      strictEqual(res.type, 'Note');
+      strictEqual(res.object.uri, `https://b.test/notes/${note.id}`);
+      // 投稿者が a.test 側で解決済みの Bob になること
+      strictEqual(res.object.userId, bobInA.id);
+    });
+  });
+});

From 92dd1347c44a6517915111326c177efedbd7efea Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Thu, 28 Aug 2025 22:18:46 +0900
Subject: [PATCH 10/20] fix

---
 packages/backend/src/server/api/endpoints/ap/show.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/backend/src/server/api/endpoints/ap/show.ts b/packages/backend/src/server/api/endpoints/ap/show.ts
index f62baf79e1..b89687acce 100644
--- a/packages/backend/src/server/api/endpoints/ap/show.ts
+++ b/packages/backend/src/server/api/endpoints/ap/show.ts
@@ -111,7 +111,7 @@ export const paramDef = {
 	type: 'object',
 	properties: {
 		uri: { type: 'string' },
-		onlyUriFetch: { type: 'boolean', optional: true, nullable: false },
+		onlyUriFetch: { type: 'boolean' },
 	},
 	required: ['uri'],
 } as const;

From e29fe18b93276734c67a8ee728288f28f4b99933 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Thu, 28 Aug 2025 23:19:06 +0900
Subject: [PATCH 11/20] WIP

---
 .../src/server/api/endpoints/ap/show.ts       | 39 ++++++++++++++-----
 .../test-federation/test/api/ap/show.test.ts  |  4 +-
 2 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/packages/backend/src/server/api/endpoints/ap/show.ts b/packages/backend/src/server/api/endpoints/ap/show.ts
index b89687acce..867a2bc71e 100644
--- a/packages/backend/src/server/api/endpoints/ap/show.ts
+++ b/packages/backend/src/server/api/endpoints/ap/show.ts
@@ -25,6 +25,7 @@ import { FetchAllowSoftFailMask } from '@/core/activitypub/misc/check-against-ur
 import { RemoteUserResolveService } from '@/core/RemoteUserResolveService.js';
 import { DI } from '@/di-symbols.js';
 import type { MiMeta } from '@/models/_.js';
+import { ApiLoggerService } from '../../ApiLoggerService.js';
 
 export const meta = {
 	tags: ['federation'],
@@ -68,6 +69,11 @@ export const meta = {
 			code: 'SOMETHING_HAPPENED_IN_FETCHING_URI',
 			id: '14d45054-9df7-4f85-9e60-343b22f16b05',
 		},
+		uriIsAcctLikeButThisIsOnlyUriFetchMode: {
+			message: 'URI is acct-like but onlyUriFetch is true.',
+			code: 'URI_IS_ACCT_LIKE_BUT_THIS_IS_ONLY_URI_FETCH_MODE',
+			id: 'b224ffe3-ae5c-44e2-9df4-f0b8662bb085',
+		},
 	},
 
 	res: {
@@ -130,28 +136,43 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 		private apPersonService: ApPersonService,
 		private apNoteService: ApNoteService,
 		private remoteUserResolveService: RemoteUserResolveService,
+		private apiLoggerService: ApiLoggerService,
 	) {
 		super(meta, paramDef, async (ps, me) => {
-			let object: SchemaType<typeof meta['res']> | null;
+			let object: SchemaType<typeof meta['res']> | null = null;
+			let acct: misskey.acct.Acct | null = null;
 
-			if (!ps.onlyUriFetch) {
+			try {
+				acct = misskey.acct.parseAcctOrUrl(ps.uri);
+			} catch (err) {
+				// nothing to do
+			}
+
+			if (!ps.onlyUriFetch && acct) {
 				try {
-					object = await this.fetchAcct(misskey.acct.parseAcctOrUrl(ps.uri), me);
+					object = await this.fetchAcct(acct, me);
 				} catch (err) {
 					if (err instanceof IdentifiableError && err.id === 'bddd9f4c-f0a8-4cac-9c0a-4e6d2fc43408') {
 						// Signin required
 						throw new ApiError(meta.errors.noSuchObject);
 					}
+
+					this.apiLoggerService.logger.warn('ap/show: fetchAcct failed', { uri: ps.uri, error: err });
 				}
 			}
 
-			try {
-				object = await this.fetchAnyUri(ps.uri, me);
-			} catch (err) {
-				if (err instanceof ApiError) {
-					throw err;
+			if (object == null) {
+				try {
+					object = await this.fetchAnyUri(ps.uri, me);
+				} catch (err) {
+					if (err instanceof ApiError) {
+						throw err;
+					}
+					if (acct) {
+						throw new ApiError(meta.errors.uriIsAcctLikeButThisIsOnlyUriFetchMode);
+					}
+					throw new ApiError(meta.errors.somethingHappenedInFetchingUri, err);
 				}
-				throw new ApiError(meta.errors.somethingHappenedInFetchingUri);
 			}
 
 			if (object) {
diff --git a/packages/backend/test-federation/test/api/ap/show.test.ts b/packages/backend/test-federation/test/api/ap/show.test.ts
index 7c35026269..a7839f5d6e 100644
--- a/packages/backend/test-federation/test/api/ap/show.test.ts
+++ b/packages/backend/test-federation/test/api/ap/show.test.ts
@@ -39,11 +39,11 @@ describe('API ap/show', () => {
       strictEqual(res.object.uri, `https://b.test/users/${bob.id}`);
     });
 
-    test('onlyUriFetch=true with acct string should fail with URI_INVALID', async () => {
+  test('onlyUriFetch=true with acct string returns generic fetch error', async () => {
       await rejects(
         async () => await alice.client.request('ap/show', { uri: `${bob.username}@b.test`, onlyUriFetch: true }),
         (err: any) => {
-          strictEqual(err.code, 'URI_INVALID');
+      strictEqual(err.code, 'URI_IS_ACCT_LIKE_BUT_THIS_IS_ONLY_URI_FETCH_MODE');
           return true;
         },
       );

From a30b029803b94822f9d08b3c8702aec86e066311 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Thu, 28 Aug 2025 23:23:09 +0900
Subject: [PATCH 12/20] :v:

---
 .../test-federation/test/api/ap/show.test.ts  | 100 ++++++++----------
 1 file changed, 47 insertions(+), 53 deletions(-)

diff --git a/packages/backend/test-federation/test/api/ap/show.test.ts b/packages/backend/test-federation/test/api/ap/show.test.ts
index a7839f5d6e..30dbc9e396 100644
--- a/packages/backend/test-federation/test/api/ap/show.test.ts
+++ b/packages/backend/test-federation/test/api/ap/show.test.ts
@@ -3,64 +3,58 @@ import * as Misskey from 'misskey-js';
 import { createAccount, resolveRemoteUser, sleep, type LoginUser } from '../../utils.js';
 
 describe('API ap/show', () => {
-  let alice: LoginUser, bob: LoginUser;
-  let bobInA: Misskey.entities.UserDetailedNotMe;
+	let alice: LoginUser, bob: LoginUser;
 
-  beforeAll(async () => {
-    [alice, bob] = await Promise.all([
-      createAccount('a.test'),
-      createAccount('b.test'),
-    ]);
+	beforeAll(async () => {
+		[alice, bob] = await Promise.all([
+			createAccount('a.test'),
+			createAccount('b.test'),
+		]);
+	});
 
-    // 事前に bob を a.test に解決してキャッシュ・同一性を取る
-    bobInA = await resolveRemoteUser('b.test', bob.id, alice);
-  });
+	describe('User resolution', () => {
+		test('resolve by acct (bob@b.test)', async () => {
+			const res = await alice.client.request('ap/show', { uri: `${bob.username}@b.test` });
+			strictEqual(res.type, 'User');
+			strictEqual(res.object.uri, `https://b.test/users/${bob.id}`);
+		});
 
-  describe('User resolution', () => {
-    test('resolve by acct (bob@b.test)', async () => {
-      const res = await alice.client.request('ap/show', { uri: `${bob.username}@b.test` });
-      strictEqual(res.type, 'User');
-      strictEqual(res.object.id, bobInA.id);
-      strictEqual(res.object.uri, `https://b.test/users/${bob.id}`);
-    });
+		test('resolve by canonical user URL (https://b.test/users/:id)', async () => {
+			const res = await alice.client.request('ap/show', { uri: `https://b.test/users/${bob.id}` });
+			strictEqual(res.type, 'User');
+			strictEqual(res.object.uri, `https://b.test/users/${bob.id}`);
+		});
 
-    test('resolve by canonical user URL (https://b.test/users/:id)', async () => {
-      const res = await alice.client.request('ap/show', { uri: `https://b.test/users/${bob.id}` });
-      strictEqual(res.type, 'User');
-      strictEqual(res.object.id, bobInA.id);
-      strictEqual(res.object.uri, `https://b.test/users/${bob.id}`);
-    });
+		test('resolve by cross-origin non-canonical URL (https://a.test/@bob@b.test)', async () => {
+			const res = await alice.client.request('ap/show', { uri: `https://a.test/@${bob.username}@b.test` });
+			strictEqual(res.type, 'User');
+			// 非正規URLから正規IDに追従して同一ユーザーになること
+			strictEqual(res.object.uri, `https://b.test/users/${bob.id}`);
+		});
 
-    test('resolve by cross-origin non-canonical URL (https://a.test/@bob@b.test)', async () => {
-      const res = await alice.client.request('ap/show', { uri: `https://a.test/@${bob.username}@b.test` });
-      strictEqual(res.type, 'User');
-      // 非正規URLから正規IDに追従して同一ユーザーになること
-      strictEqual(res.object.id, bobInA.id);
-      strictEqual(res.object.uri, `https://b.test/users/${bob.id}`);
-    });
+		test('onlyUriFetch=true with acct string returns generic fetch error', async () => {
+			await rejects(
+				async () => await alice.client.request('ap/show', { uri: `${bob.username}@b.test`, onlyUriFetch: true }),
+				(err: any) => {
+					strictEqual(err.code, 'URI_IS_ACCT_LIKE_BUT_THIS_IS_ONLY_URI_FETCH_MODE');
+					return true;
+				},
+			);
+		});
+	});
 
-  test('onlyUriFetch=true with acct string returns generic fetch error', async () => {
-      await rejects(
-        async () => await alice.client.request('ap/show', { uri: `${bob.username}@b.test`, onlyUriFetch: true }),
-        (err: any) => {
-      strictEqual(err.code, 'URI_IS_ACCT_LIKE_BUT_THIS_IS_ONLY_URI_FETCH_MODE');
-          return true;
-        },
-      );
-    });
-  });
+	describe('Note resolution', () => {
+		test('resolve by note URL (https://b.test/notes/:id)', async () => {
+			const note = (await bob.client.request('notes/create', { text: 'hello from Bob' })).createdNote;
+			// 伝搬待ち
+			await sleep();
 
-  describe('Note resolution', () => {
-    test('resolve by note URL (https://b.test/notes/:id)', async () => {
-      const note = (await bob.client.request('notes/create', { text: 'hello from Bob' })).createdNote;
-      // 伝搬待ち
-      await sleep();
-
-      const res = await alice.client.request('ap/show', { uri: `https://b.test/notes/${note.id}` });
-      strictEqual(res.type, 'Note');
-      strictEqual(res.object.uri, `https://b.test/notes/${note.id}`);
-      // 投稿者が a.test 側で解決済みの Bob になること
-      strictEqual(res.object.userId, bobInA.id);
-    });
-  });
+			const res = await alice.client.request('ap/show', { uri: `https://b.test/notes/${note.id}` });
+			strictEqual(res.type, 'Note');
+			strictEqual(res.object.uri, `https://b.test/notes/${note.id}`);
+			// 投稿者が a.test 側で解決済みの Bob になること
+			strictEqual(res.object.user.username, bob.username);
+			strictEqual(res.object.user.host, 'b.test');
+		});
+	});
 });

From f2115a06c9cd4eb98d825cc9364bb20280d751f5 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Thu, 28 Aug 2025 23:42:03 +0900
Subject: [PATCH 13/20] api

---
 packages/misskey-js/etc/misskey-js.api.md | 2 +-
 packages/misskey-js/src/autogen/types.ts  | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/packages/misskey-js/etc/misskey-js.api.md b/packages/misskey-js/etc/misskey-js.api.md
index 6ddff405e4..70955a2a73 100644
--- a/packages/misskey-js/etc/misskey-js.api.md
+++ b/packages/misskey-js/etc/misskey-js.api.md
@@ -2815,7 +2815,7 @@ type ModerationLog = {
     id: ID;
     createdAt: DateString;
     userId: User['id'];
-    user: UserDetailedNotMe | null;
+    user: UserDetailedNotMe;
 } & ({
     type: 'updateServerSettings';
     info: ModerationLogPayloads['updateServerSettings'];
diff --git a/packages/misskey-js/src/autogen/types.ts b/packages/misskey-js/src/autogen/types.ts
index d92ef599f3..da04e975d6 100644
--- a/packages/misskey-js/src/autogen/types.ts
+++ b/packages/misskey-js/src/autogen/types.ts
@@ -13554,6 +13554,7 @@ export interface operations {
             content: {
                 'application/json': {
                     uri: string;
+                    onlyUriFetch?: boolean;
                 };
             };
         };

From d90593693097e1fc02530ad0884498aab1a6d1f5 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Thu, 28 Aug 2025 23:44:52 +0900
Subject: [PATCH 14/20] build-misskey-js-with-types

---
 packages/misskey-js/etc/misskey-js.api.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/misskey-js/etc/misskey-js.api.md b/packages/misskey-js/etc/misskey-js.api.md
index ecce5bd8e6..3388a3d9a9 100644
--- a/packages/misskey-js/etc/misskey-js.api.md
+++ b/packages/misskey-js/etc/misskey-js.api.md
@@ -2809,7 +2809,7 @@ type ModerationLog = {
     id: ID;
     createdAt: DateString;
     userId: User['id'];
-    user: UserDetailedNotMe | null;
+    user: UserDetailedNotMe;
 } & ({
     type: 'updateServerSettings';
     info: ModerationLogPayloads['updateServerSettings'];

From 42946e3f68c79d88b298ca9136234b0034ab8aa0 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Fri, 29 Aug 2025 00:09:54 +0900
Subject: [PATCH 15/20] fix test

---
 packages/backend/test-federation/test/user.test.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/backend/test-federation/test/user.test.ts b/packages/backend/test-federation/test/user.test.ts
index ebbe9ff5ba..3b9722975d 100644
--- a/packages/backend/test-federation/test/user.test.ts
+++ b/packages/backend/test-federation/test/user.test.ts
@@ -516,7 +516,7 @@ describe('User', () => {
 				await rejects(
 					async () => await resolveRemoteUser('a.test', alice.id, bob),
 					(err: any) => {
-						strictEqual(err.code, 'INTERNAL_ERROR');
+						strictEqual(err.code, 'SOMETHING_HAPPENED_IN_FETCHING_URI');
 						return true;
 					},
 				);
@@ -551,7 +551,7 @@ describe('User', () => {
 				await rejects(
 					async () => await resolveRemoteUser('a.test', alice.id, bob),
 					(err: any) => {
-						strictEqual(err.code, 'INTERNAL_ERROR');
+						strictEqual(err.code, 'SOMETHING_HAPPENED_IN_FETCHING_URI');
 						return true;
 					},
 				);

From 60dd7864ce6c54ff71ca755c305e0a830d94d9b1 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Fri, 29 Aug 2025 00:11:29 +0900
Subject: [PATCH 16/20] fix lint

---
 packages/backend/src/server/api/endpoints/ap/show.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/backend/src/server/api/endpoints/ap/show.ts b/packages/backend/src/server/api/endpoints/ap/show.ts
index 867a2bc71e..a3dc795df3 100644
--- a/packages/backend/src/server/api/endpoints/ap/show.ts
+++ b/packages/backend/src/server/api/endpoints/ap/show.ts
@@ -195,7 +195,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 		return {
 			type: 'User',
 			object: await this.userEntityService.pack(user, me, { schema: 'UserDetailed' }),
-		}
+		};
 	}
 
 	/**

From 6fa73a2e26fe5eb282a2a0b3ee9d6e5c888a4525 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Fri, 29 Aug 2025 16:17:10 +0900
Subject: [PATCH 17/20] =?UTF-8?q?=E4=BB=95=E6=A7=98=E5=A4=89=E6=9B=B4:=20U?=
 =?UTF-8?q?RL=E3=81=AE=E6=9C=80=E5=BE=8C=E3=81=8C@username=E3=81=A7?=
 =?UTF-8?q?=E7=B5=82=E3=82=8F=E3=81=A3=E3=81=A6=E3=81=84=E3=82=8B=E5=A0=B4?=
 =?UTF-8?q?=E5=90=88=E3=81=AB=E3=81=A0=E3=81=91acct=20like=20url=E3=81=A8?=
 =?UTF-8?q?=E3=81=97=E3=81=A6=E8=AA=8D=E7=9F=A5=E3=81=99=E3=82=8B=E3=82=88?=
 =?UTF-8?q?=E3=81=86=E3=81=AB?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 packages/misskey-js/src/acct.ts  |  7 ++++++-
 packages/misskey-js/test/acct.ts | 19 ++++++++++++++++++-
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/packages/misskey-js/src/acct.ts b/packages/misskey-js/src/acct.ts
index 74e0ff06f0..e30599b650 100644
--- a/packages/misskey-js/src/acct.ts
+++ b/packages/misskey-js/src/acct.ts
@@ -29,8 +29,13 @@ export function parse(acct: string): Acct {
 
 export function parseUrl(str: string): Acct {
 	const url = new URL(str);
-	const path = url.pathname.split('/').find((p) => p.startsWith('@') && p.length >= 2);
+	const splited = url.pathname.split('/');
+	let path = splited.pop();
+	if (path === '') path = splited.pop(); // If the last segment is empty due to a trailing '/', use the previous segment
+
 	if (!path) throw new Error('This url is not acct like.');
+	if (!path.startsWith('@')) throw new Error('This url is not acct like.');
+	if (path.length <= 1) throw new Error('This url is not acct like.');
 
 	const split = path.split('@', 3); // ['', 'username', 'other.example.com']
 
diff --git a/packages/misskey-js/test/acct.ts b/packages/misskey-js/test/acct.ts
index fd59a82c9d..510b106ad2 100644
--- a/packages/misskey-js/test/acct.ts
+++ b/packages/misskey-js/test/acct.ts
@@ -39,9 +39,26 @@ function testParseUrl(fn: (acct: string) => acct.Acct) {
 		expect(res).toEqual({ username: 'alice', host: 'other.example.com' });
 	});
 
-	it('throws on non-acct-like url path', () => {
+	it('throws on non-acct-like url path (root)', () => {
+		expect(() => fn('https://example.com')).toThrowError();
+	});
+
+	it('throws on non-acct-like url path (users/alice)', () => {
 		expect(() => fn('https://example.com/users/alice')).toThrowError();
 	});
+
+	it('throws ended with @', () => {
+		expect(() => fn('https://example.com/@')).toThrowError();
+	});
+
+	it('parses url ended with /', () => {
+		const res = fn('https://example.com/@alice/');
+		expect(res).toEqual({ username: 'alice', host: 'example.com' });
+	});
+
+	it('throws url have @username path but ended with sub directory', () => {
+		expect(() => fn('https://example.com/@alice/subdir')).toThrowError();
+	});
 }
 
 describe('acct.parse', () => {

From 289051b3149327a39920f507179c937d61eb84e2 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Fri, 29 Aug 2025 16:50:21 +0900
Subject: [PATCH 18/20] throws url with search params or hash

---
 packages/misskey-js/etc/misskey-js.api.md |  8 +++++++-
 packages/misskey-js/src/acct.ts           | 16 +++++++++++++---
 packages/misskey-js/test/acct.ts          |  8 ++++++++
 3 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/packages/misskey-js/etc/misskey-js.api.md b/packages/misskey-js/etc/misskey-js.api.md
index 70955a2a73..423b3be916 100644
--- a/packages/misskey-js/etc/misskey-js.api.md
+++ b/packages/misskey-js/etc/misskey-js.api.md
@@ -28,7 +28,8 @@ declare namespace acct {
         parseUrl,
         parseAcctOrUrl,
         toString_2 as toString,
-        Acct
+        Acct,
+        UrlIsNotAcctLikeError
     }
 }
 export { acct }
@@ -3640,6 +3641,11 @@ type TestResponse = operations['test']['responses']['200']['content']['applicati
 // @public (undocumented)
 function toString_2(acct: Acct): string;
 
+// @public (undocumented)
+class UrlIsNotAcctLikeError extends Error {
+    constructor();
+}
+
 // @public (undocumented)
 type User = components['schemas']['User'];
 
diff --git a/packages/misskey-js/src/acct.ts b/packages/misskey-js/src/acct.ts
index e30599b650..e8c4524ec4 100644
--- a/packages/misskey-js/src/acct.ts
+++ b/packages/misskey-js/src/acct.ts
@@ -27,15 +27,25 @@ export function parse(acct: string): Acct {
 	return { username: split[0], host: split[1] || null };
 }
 
+export class UrlIsNotAcctLikeError extends Error {
+	constructor() {
+		super('This url is not acct like.');
+	}
+}
+
 export function parseUrl(str: string): Acct {
 	const url = new URL(str);
+
+	if (url.hash.length > 0) throw new UrlIsNotAcctLikeError();
+	if (url.search.length > 0) throw new UrlIsNotAcctLikeError();
+
 	const splited = url.pathname.split('/');
 	let path = splited.pop();
 	if (path === '') path = splited.pop(); // If the last segment is empty due to a trailing '/', use the previous segment
 
-	if (!path) throw new Error('This url is not acct like.');
-	if (!path.startsWith('@')) throw new Error('This url is not acct like.');
-	if (path.length <= 1) throw new Error('This url is not acct like.');
+	if (!path) throw new UrlIsNotAcctLikeError();
+	if (!path.startsWith('@')) throw new UrlIsNotAcctLikeError();
+	if (path.length <= 1) throw new UrlIsNotAcctLikeError();
 
 	const split = path.split('@', 3); // ['', 'username', 'other.example.com']
 
diff --git a/packages/misskey-js/test/acct.ts b/packages/misskey-js/test/acct.ts
index 510b106ad2..4200e593de 100644
--- a/packages/misskey-js/test/acct.ts
+++ b/packages/misskey-js/test/acct.ts
@@ -59,6 +59,14 @@ function testParseUrl(fn: (acct: string) => acct.Acct) {
 	it('throws url have @username path but ended with sub directory', () => {
 		expect(() => fn('https://example.com/@alice/subdir')).toThrowError();
 	});
+
+	it('throws url with search params', () => {
+		expect(() => fn('https://example.com/@alice?foo=bar')).toThrowError();
+	});
+
+	it('throws url with hash', () => {
+		expect(() => fn('https://example.com/@alice#fragment')).toThrowError();
+	});
 }
 
 describe('acct.parse', () => {

From 5a698687036698a95330a5557b96b5899d41f0cf Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Sat, 30 Aug 2025 17:15:01 +0900
Subject: [PATCH 19/20] revert ap/show changes

---
 .../src/server/api/endpoints/ap/show.ts       | 78 +------------------
 .../test-federation/test/api/ap/show.test.ts  | 29 +++----
 2 files changed, 16 insertions(+), 91 deletions(-)

diff --git a/packages/backend/src/server/api/endpoints/ap/show.ts b/packages/backend/src/server/api/endpoints/ap/show.ts
index a3dc795df3..4afed7dc5c 100644
--- a/packages/backend/src/server/api/endpoints/ap/show.ts
+++ b/packages/backend/src/server/api/endpoints/ap/show.ts
@@ -5,7 +5,6 @@
 
 import { Inject, Injectable } from '@nestjs/common';
 import ms from 'ms';
-import * as misskey from 'misskey-js';
 import { Endpoint } from '@/server/api/endpoint-base.js';
 import type { MiNote } from '@/models/Note.js';
 import type { MiLocalUser, MiUser } from '@/models/User.js';
@@ -22,10 +21,6 @@ import { bindThis } from '@/decorators.js';
 import { ApiError } from '../../error.js';
 import { IdentifiableError } from '@/misc/identifiable-error.js';
 import { FetchAllowSoftFailMask } from '@/core/activitypub/misc/check-against-url.js';
-import { RemoteUserResolveService } from '@/core/RemoteUserResolveService.js';
-import { DI } from '@/di-symbols.js';
-import type { MiMeta } from '@/models/_.js';
-import { ApiLoggerService } from '../../ApiLoggerService.js';
 
 export const meta = {
 	tags: ['federation'],
@@ -64,16 +59,6 @@ export const meta = {
 			code: 'NO_SUCH_OBJECT',
 			id: 'dc94d745-1262-4e63-a17d-fecaa57efc82',
 		},
-		somethingHappenedInFetchingUri: {
-			message: 'Something happened while fetching the URI.',
-			code: 'SOMETHING_HAPPENED_IN_FETCHING_URI',
-			id: '14d45054-9df7-4f85-9e60-343b22f16b05',
-		},
-		uriIsAcctLikeButThisIsOnlyUriFetchMode: {
-			message: 'URI is acct-like but onlyUriFetch is true.',
-			code: 'URI_IS_ACCT_LIKE_BUT_THIS_IS_ONLY_URI_FETCH_MODE',
-			id: 'b224ffe3-ae5c-44e2-9df4-f0b8662bb085',
-		},
 	},
 
 	res: {
@@ -117,7 +102,6 @@ export const paramDef = {
 	type: 'object',
 	properties: {
 		uri: { type: 'string' },
-		onlyUriFetch: { type: 'boolean' },
 	},
 	required: ['uri'],
 } as const;
@@ -125,9 +109,6 @@ export const paramDef = {
 @Injectable()
 export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-disable-line import/no-default-export
 	constructor(
-		@Inject(DI.meta)
-		private serverSettings: MiMeta,
-
 		private utilityService: UtilityService,
 		private userEntityService: UserEntityService,
 		private noteEntityService: NoteEntityService,
@@ -135,46 +116,9 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 		private apDbResolverService: ApDbResolverService,
 		private apPersonService: ApPersonService,
 		private apNoteService: ApNoteService,
-		private remoteUserResolveService: RemoteUserResolveService,
-		private apiLoggerService: ApiLoggerService,
 	) {
 		super(meta, paramDef, async (ps, me) => {
-			let object: SchemaType<typeof meta['res']> | null = null;
-			let acct: misskey.acct.Acct | null = null;
-
-			try {
-				acct = misskey.acct.parseAcctOrUrl(ps.uri);
-			} catch (err) {
-				// nothing to do
-			}
-
-			if (!ps.onlyUriFetch && acct) {
-				try {
-					object = await this.fetchAcct(acct, me);
-				} catch (err) {
-					if (err instanceof IdentifiableError && err.id === 'bddd9f4c-f0a8-4cac-9c0a-4e6d2fc43408') {
-						// Signin required
-						throw new ApiError(meta.errors.noSuchObject);
-					}
-
-					this.apiLoggerService.logger.warn('ap/show: fetchAcct failed', { uri: ps.uri, error: err });
-				}
-			}
-
-			if (object == null) {
-				try {
-					object = await this.fetchAnyUri(ps.uri, me);
-				} catch (err) {
-					if (err instanceof ApiError) {
-						throw err;
-					}
-					if (acct) {
-						throw new ApiError(meta.errors.uriIsAcctLikeButThisIsOnlyUriFetchMode);
-					}
-					throw new ApiError(meta.errors.somethingHappenedInFetchingUri, err);
-				}
-			}
-
+			const object = await this.fetchAny(ps.uri, me);
 			if (object) {
 				return object;
 			} else {
@@ -183,26 +127,11 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 		});
 	}
 
-	private async fetchAcct(acct: misskey.acct.Acct, me: MiLocalUser | null | undefined): Promise<SchemaType<typeof meta['res']> | null> {
-		if (this.serverSettings.ugcVisibilityForVisitor === 'local' && me == null) {
-			throw new IdentifiableError('bddd9f4c-f0a8-4cac-9c0a-4e6d2fc43408', 'Signin required');
-		}
-
-		const user = await this.remoteUserResolveService.resolveUser(acct.username, acct.host);
-
-		if (!user) return null;
-
-		return {
-			type: 'User',
-			object: await this.userEntityService.pack(user, me, { schema: 'UserDetailed' }),
-		};
-	}
-
-	/**
+	/***
 	 * URIからUserかNoteを解決する
 	 */
 	@bindThis
-	private async fetchAnyUri(uri: string, me: MiLocalUser | null | undefined): Promise<SchemaType<typeof meta['res']> | null> {
+	private async fetchAny(uri: string, me: MiLocalUser | null | undefined): Promise<SchemaType<typeof meta['res']> | null> {
 		if (!this.utilityService.isFederationAllowedUri(uri)) {
 			throw new ApiError(meta.errors.federationNotAllowed);
 		}
@@ -245,6 +174,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 						throw new ApiError(meta.errors.responseInvalid);
 				}
 			}
+
 			throw new ApiError(meta.errors.requestFailed);
 		});
 
diff --git a/packages/backend/test-federation/test/api/ap/show.test.ts b/packages/backend/test-federation/test/api/ap/show.test.ts
index 30dbc9e396..eb949754d7 100644
--- a/packages/backend/test-federation/test/api/ap/show.test.ts
+++ b/packages/backend/test-federation/test/api/ap/show.test.ts
@@ -13,33 +13,28 @@ describe('API ap/show', () => {
 	});
 
 	describe('User resolution', () => {
-		test('resolve by acct (bob@b.test)', async () => {
-			const res = await alice.client.request('ap/show', { uri: `${bob.username}@b.test` });
-			strictEqual(res.type, 'User');
-			strictEqual(res.object.uri, `https://b.test/users/${bob.id}`);
-		});
-
 		test('resolve by canonical user URL (https://b.test/users/:id)', async () => {
 			const res = await alice.client.request('ap/show', { uri: `https://b.test/users/${bob.id}` });
 			strictEqual(res.type, 'User');
 			strictEqual(res.object.uri, `https://b.test/users/${bob.id}`);
 		});
 
-		test('resolve by cross-origin non-canonical URL (https://a.test/@bob@b.test)', async () => {
-			const res = await alice.client.request('ap/show', { uri: `https://a.test/@${bob.username}@b.test` });
+		test('resolve by user profile URL (https://b.test/@bob)', async () => {
+			const res = await alice.client.request('ap/show', { uri: `https://b.test/@${bob.username}` });
 			strictEqual(res.type, 'User');
-			// 非正規URLから正規IDに追従して同一ユーザーになること
 			strictEqual(res.object.uri, `https://b.test/users/${bob.id}`);
 		});
 
-		test('onlyUriFetch=true with acct string returns generic fetch error', async () => {
-			await rejects(
-				async () => await alice.client.request('ap/show', { uri: `${bob.username}@b.test`, onlyUriFetch: true }),
-				(err: any) => {
-					strictEqual(err.code, 'URI_IS_ACCT_LIKE_BUT_THIS_IS_ONLY_URI_FETCH_MODE');
-					return true;
-				},
-			);
+		test('resolve local user by local profile url', async () => {
+			const res = await alice.client.request('ap/show', { uri: `https://a.test/@${alice.username}` });
+			strictEqual(res.type, 'User');
+			strictEqual(res.object.id, alice.id);
+		});
+
+		test('resolve remote user by local profile URL (https://a.test/@bob@b.test)', async () => {
+			const res = await alice.client.request('ap/show', { uri: `https://a.test/@${bob.username}@b.test` });
+			strictEqual(res.type, 'User');
+			strictEqual(res.object.uri, `https://b.test/users/${bob.id}`);
 		});
 	});
 

From a3ed7d994b831a9103325b375c1f79a21117dd72 Mon Sep 17 00:00:00 2001
From: tamaina <tamaina@hotmail.co.jp>
Date: Sat, 30 Aug 2025 17:22:22 +0900
Subject: [PATCH 20/20] =?UTF-8?q?pathname=E3=81=AE=E3=83=AB=E3=83=BC?=
 =?UTF-8?q?=E3=83=88=E3=81=8C@=E3=81=A7=E5=A7=8B=E3=81=BE=E3=82=8B?=
 =?UTF-8?q?=E3=81=A8=E3=81=8D=E3=81=A0=E3=81=91acct=20like=20url=E3=81=A8?=
 =?UTF-8?q?=E3=81=99=E3=82=8B?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 packages/misskey-js/src/acct.ts | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/packages/misskey-js/src/acct.ts b/packages/misskey-js/src/acct.ts
index e8c4524ec4..06dcd6fa2c 100644
--- a/packages/misskey-js/src/acct.ts
+++ b/packages/misskey-js/src/acct.ts
@@ -33,6 +33,9 @@ export class UrlIsNotAcctLikeError extends Error {
 	}
 }
 
+/**
+ * Only supports `https?://example.com/@username` or `https?://example.com/@username@other.example.com`
+ */
 export function parseUrl(str: string): Acct {
 	const url = new URL(str);
 
@@ -40,8 +43,7 @@ export function parseUrl(str: string): Acct {
 	if (url.search.length > 0) throw new UrlIsNotAcctLikeError();
 
 	const splited = url.pathname.split('/');
-	let path = splited.pop();
-	if (path === '') path = splited.pop(); // If the last segment is empty due to a trailing '/', use the previous segment
+	const path = splited[1];
 
 	if (!path) throw new UrlIsNotAcctLikeError();
 	if (!path.startsWith('@')) throw new UrlIsNotAcctLikeError();