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+# Issue #267/#269 索引组织迁移 + artifact 采纳 — 实施计划(0.0.103)
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** 按设计文档 `2026-07-22-issue267-269-index-artifact-and-org-migration-design.md` 落地 D1–D5,单 PR 携版本 0.0.103,合入后走发布闭环 + xlings 全生态验证。
+
+**Architecture:** 新/旧 URL 与 artifact base 收敛为 `mcpp::config` 三常量;`canonicalize_legacy_index_names` 导出并承担"URL 归一→名字迁移→artifact 内存级填充→去重"单循环;文件层治愈只做最小文本手术(config.toml URL 替换、.xlings.json URL 替换 + artifact 注入,幂等闸=已含 res base);seed 管线由 `pair` 升级为 `SeedRepo{name,url,artifact,source}`,非空才发射,零 diff 门。
+
+**Tech Stack:** C++23 modules(自托管 `mcpp build`/`mcpp test`)、gtest 单测(tests/unit)、bash e2e(tests/e2e)、gh CLI。
+
+## Global Constraints
+
+- 版本:`mcpp.toml` version 与 `src/toolchain/fingerprint.cppm` MCPP_VERSION **同 commit 同步**为 `0.0.103`(不一致 release smoke 失败)。
+- 新 URL `https://github.com/mcpplibs/mcpp-index.git`;旧 URL `https://github.com/mcpp-community/mcpp-index.git`;artifact base `https://github.com/xlings-res/mcpp-index`。
+- 无 artifact 的仓 seed 输出**逐字节不变**(零 diff 门)。
+- `.xlings.json` 迁移**不整文件重生成**(保 subos/版本绑定),只做目标文本替换,双间距变体(mcpp pretty / xlings compact)。
+- `mcpp.fallback.config_migration` 是叶子模块,不 import mcpp.config —— URL 字面量在此重复是接受的(与现有 name 迁移同风格)。
+- 构建/测试命令:`mcpp build`;`MCPP_FRESH=$(realpath $(find target -type f -name mcpp -printf '%T@ %p\n' | sort -rn | head -1 | cut -d' ' -f2))`;`"$MCPP_FRESH" test`;e2e 单跑 `MCPP="$MCPP_FRESH" bash tests/e2e/<n>.sh`。
+- 分支:`feat/index-artifact-0.0.103` off `origin/main`(a768f48);单 PR;合并 `gh pr merge --squash --admin`。
+
+---
+
+### Task 0: 分支与文档
+
+- [ ] `git checkout -b feat/index-artifact-0.0.103 origin/main`
+- [ ] `git add .agents/docs/2026-07-22-issue267-269-*.md && git commit -m "docs: index org migration + artifact adoption design & impl plan (#267 #269)"`
+
+### Task 1: D1 — 常量 + canonicalize 导出与 URL 迁移(TDD)
+
+**Files:**
+- Modify: `src/config.cppm`(导出区加三常量与 `canonicalize_legacy_index_names` 声明;原匿名 ns 实现移出;`:360` 模板 URL、`:575` add_default URL)
+- Modify: `src/fallback/config_migration.cppm`(两迁移函数加 URL 替换)
+- Modify: `src/publish/pipeline.cppm:158`、`docs/00-getting-started.md:98`、`docs/04-build-from-source.md:96`、`docs/zh/00-getting-started.md:99`、`docs/zh/04-build-from-source.md:103`
+- Test: `tests/unit/test_config.cpp`
+
+**Interfaces (produces):**
+```cpp
+// mcpp::config, exported
+inline constexpr std::string_view kMcpplibsIndexUrl       = "https://github.com/mcpplibs/mcpp-index.git";
+inline constexpr std::string_view kMcpplibsIndexUrlLegacy = "https://github.com/mcpp-community/mcpp-index.git";
+inline constexpr std::string_view kMcpplibsIndexArtifact  = "https://github.com/xlings-res/mcpp-index";
+void canonicalize_legacy_index_names(GlobalConfig& cfg);   // 导出(可测性)
+```
+
+- [ ] **Step 1: 失败单测**(`test_config.cpp` 末尾追加;`import mcpp.fallback.config_migration;` 加到文件头 import 区)
+
+```cpp
+TEST(ConfigIndexMigration, CanonicalizeRewritesOrgAndNameAndFillsArtifact) {
+    mcpp::config::GlobalConfig cfg;
+    cfg.defaultIndex = "mcpp-index";
+    cfg.indexRepos.push_back({ "mcpp-index",
+        std::string(mcpp::config::kMcpplibsIndexUrlLegacy) });
+    mcpp::config::canonicalize_legacy_index_names(cfg);
+    ASSERT_EQ(cfg.indexRepos.size(), 1u);
+    EXPECT_EQ(cfg.defaultIndex, "mcpplibs");
+    EXPECT_EQ(cfg.indexRepos[0].name, "mcpplibs");
+    EXPECT_EQ(cfg.indexRepos[0].url,  mcpp::config::kMcpplibsIndexUrl);
+    EXPECT_EQ(cfg.indexRepos[0].artifact, mcpp::config::kMcpplibsIndexArtifact);
+}
+
+TEST(ConfigIndexMigration, CanonicalizeFoldsLegacyAndDefaultEntries) {
+    mcpp::config::GlobalConfig cfg;
+    cfg.indexRepos.push_back({ "mcpplibs", std::string(mcpp::config::kMcpplibsIndexUrlLegacy) });
+    cfg.indexRepos.push_back({ "mcpplibs", std::string(mcpp::config::kMcpplibsIndexUrl) });
+    mcpp::config::canonicalize_legacy_index_names(cfg);
+    EXPECT_EQ(cfg.indexRepos.size(), 1u);
+}
+
+TEST(ConfigIndexMigration, CanonicalizeRespectsExplicitGitSourceAndForeignRepos) {
+    mcpp::config::GlobalConfig cfg;
+    mcpp::config::IndexRepo git{ "mcpplibs", std::string(mcpp::config::kMcpplibsIndexUrl) };
+    git.source = "git";
+    cfg.indexRepos.push_back(git);
+    cfg.indexRepos.push_back({ "other", "https://example.com/other-index.git" });
+    mcpp::config::canonicalize_legacy_index_names(cfg);
+    EXPECT_TRUE(cfg.indexRepos[0].artifact.empty());
+    EXPECT_TRUE(cfg.indexRepos[1].artifact.empty());
+    EXPECT_EQ(cfg.indexRepos[1].url, "https://example.com/other-index.git");
+}
+
+TEST(ConfigIndexMigration, MigrateConfigTomlRewritesOrgUrlIdempotently) {
+    auto dir = make_tempdir("mcpp-migrate-toml");
+    auto p = dir / "config.toml";
+    { std::ofstream os(p); os <<
+        "[index]\ndefault = \"mcpplibs\"\n\n[index.repos.\"mcpplibs\"]\n"
+        "url = \"https://github.com/mcpp-community/mcpp-index.git\"\n"; }
+    EXPECT_TRUE(mcpp::fallback::migrate_config_toml_index_names(p));
+    std::stringstream ss; ss << std::ifstream(p).rdbuf();
+    EXPECT_NE(ss.str().find("github.com/mcpplibs/mcpp-index.git"), std::string::npos);
+    EXPECT_EQ(ss.str().find("mcpp-community/mcpp-index"), std::string::npos);
+    EXPECT_FALSE(mcpp::fallback::migrate_config_toml_index_names(p));  // 幂等
+    std::filesystem::remove_all(dir);
+}
+```
+
+注:`IndexRepo` 的 `source`/`artifact` 字段 Task 2 才加 —— 本任务与 Task 2 的实现同 commit 落(测试先全写,分两步跑)。若想严格分步,`CanonicalizeRespectsExplicitGitSource` 测试留到 Task 2。
+
+- [ ] **Step 2: 跑测确认编译失败**(常量/导出不存在):`mcpp build` 期望 FAIL
+- [ ] **Step 3: 实现**——config.cppm 导出区(`struct IndexRepo` 后)加三常量;把 `canonicalize_legacy_index_names` 从匿名 ns 移到导出区,实现:
+
+```cpp
+void canonicalize_legacy_index_names(GlobalConfig& cfg) {
+    if (cfg.defaultIndex == "mcpp-index") cfg.defaultIndex = "mcpplibs";
+    std::vector<IndexRepo> normalized;
+    for (auto r : cfg.indexRepos) {
+        // ① 组织迁移(先于名字判断与去重:老配置匹配 + 新旧条目可折叠)
+        if (r.url == kMcpplibsIndexUrlLegacy) r.url = std::string(kMcpplibsIndexUrl);
+        // ② 名字迁移(URL 已归一,只认新 URL)
+        if (r.name == "mcpp-index" && r.url == kMcpplibsIndexUrl) r.name = "mcpplibs";
+        // ③ 内存级 artifact 填充(官方仓、未显式退出、未自定义)——Task 2 落地字段后启用
+        if (r.url == kMcpplibsIndexUrl && r.artifact.empty() && r.source != "git")
+            r.artifact = std::string(kMcpplibsIndexArtifact);
+        bool duplicate = std::any_of(normalized.begin(), normalized.end(),
+            [&](const IndexRepo& e) { return e.name == r.name && e.url == r.url; });
+        if (!duplicate) normalized.push_back(std::move(r));
+    }
+    cfg.indexRepos = std::move(normalized);
+}
+```
+
+`config_migration.cppm` 两函数各加(在现有 replace 之后):
+```cpp
+replace_all(updated, "https://github.com/mcpp-community/mcpp-index.git",
+                     "https://github.com/mcpplibs/mcpp-index.git");
+```
+模板 `:360`、`add_default` `:575` 改用 `kMcpplibsIndexUrl`(模板是字符串字面量,直接写新 URL);`publish/pipeline.cppm:158` Fork 行 → `https://github.com/mcpplibs/mcpp-index`;docs 4 处链接同改。
+
+- [ ] **Step 4: `mcpp build && "$MCPP_FRESH" test`** 期望 PASS(新测试含 Task 2 字段的暂缓)
+- [ ] **Step 5: Commit** `fix(index): migrate mcpplibs index URL to mcpplibs org (#267-A)`
+
+### Task 2: D2 — SeedRepo 管线 + IndexRepo/TOML/模板 artifact
+
+**Files:**
+- Modify: `src/config.cppm`(IndexRepo 加字段:36;TOML 读 artifact/source:535-543;模板:359-361;add_default:571-575;write_default_xlings_json:374-396;print_env:663-668)
+- Modify: `src/xlings.cppm`(SeedRepo struct + seed_xlings_json 签名/发射:250-253、1110-1150)
+- Test: `tests/unit/test_xlings.cpp`、`tests/unit/test_config.cpp`
+
+**Interfaces (produces):**
+```cpp
+// mcpp::config
+struct IndexRepo { std::string name, url, artifact, source; };
+// mcpp::xlings
+struct SeedRepo { std::string name, url, artifact, source; };
+void seed_xlings_json(const Env&, std::span<const SeedRepo>,
+                      std::string_view mirror = "auto", const ProjectEnv& = {});
+```
+
+- [ ] **Step 1: 失败单测**(`test_xlings.cpp`,`import mcpp.xlings;` 已有则复用其 temp-dir 惯例)
+
+```cpp
+TEST(XlingsSeed, PlainRepoEmissionIsByteStable) {   // 零 diff 门
+    auto dir = make_tempdir("mcpp-seed-plain");
+    mcpp::xlings::Env env; env.home = dir;
+    std::vector<mcpp::xlings::SeedRepo> repos{ { "mcpplibs", "https://x.git", "", "" } };
+    mcpp::xlings::seed_xlings_json(env, repos);
+    std::stringstream ss; ss << std::ifstream(dir / ".xlings.json").rdbuf();
+    EXPECT_NE(ss.str().find(
+        "    { \"name\": \"mcpplibs\", \"url\": \"https://x.git\" }\n"), std::string::npos);
+    EXPECT_EQ(ss.str().find("artifact"), std::string::npos);
+    std::filesystem::remove_all(dir);
+}
+
+TEST(XlingsSeed, ArtifactAndSourceEmittedWhenSet) {
+    auto dir = make_tempdir("mcpp-seed-art");
+    mcpp::xlings::Env env; env.home = dir;
+    std::vector<mcpp::xlings::SeedRepo> repos{
+        { "mcpplibs", "https://x.git", "https://github.com/xlings-res/mcpp-index", "auto" } };
+    mcpp::xlings::seed_xlings_json(env, repos);
+    std::stringstream ss; ss << std::ifstream(dir / ".xlings.json").rdbuf();
+    EXPECT_NE(ss.str().find("\"url\": \"https://x.git\", \"artifact\": "
+        "\"https://github.com/xlings-res/mcpp-index\", \"source\": \"auto\""), std::string::npos);
+    std::filesystem::remove_all(dir);
+}
+```
+
+- [ ] **Step 2: 编译失败确认**(SeedRepo 不存在)
+- [ ] **Step 3: 实现**——`xlings.cppm` 声明区加 `struct SeedRepo { std::string name, url, artifact, source; };`,签名改 `std::span<const SeedRepo>`;发射循环:
+
+```cpp
+for (std::size_t i = 0; i < repos.size(); ++i) {
+    json += std::format("    {{ \"name\": \"{}\", \"url\": \"{}\"",
+                        json_escape(repos[i].name), json_escape(repos[i].url));
+    if (!repos[i].artifact.empty())
+        json += std::format(", \"artifact\": \"{}\"", json_escape(repos[i].artifact));
+    if (!repos[i].source.empty())
+        json += std::format(", \"source\": \"{}\"", json_escape(repos[i].source));
+    json += std::format(" }}{}\n", i + 1 == repos.size() ? "" : ",");
+}
+```
+
+`config.cppm`:IndexRepo 加 `artifact`/`source`;TOML 解析读两 key(可选 string);`write_default_xlings_json` pairs→`std::vector<mcpp::xlings::SeedRepo>` 直传四字段;模板加:
+```toml
+[index.repos."mcpplibs"]
+url      = "https://github.com/mcpplibs/mcpp-index.git"
+artifact = "https://github.com/xlings-res/mcpp-index"
+# source = "auto"  # default: artifact first, git fallback; set "git" to force git
+```
+`add_default` lambda 加 artifact 形参并给 mcpplibs 传 `kMcpplibsIndexArtifact`;`print_env` 的 repo 行追加 ` [artifact]` 标记(`r.artifact` 非空时);`ensure_project_index_dir` 的 `customRepos` 改 `std::vector<mcpp::xlings::SeedRepo>`(artifact 字段 Task 4 接入,先留空串)。canonicalize 的 ③ 分支此时编译生效。
+
+- [ ] **Step 4: `mcpp build && "$MCPP_FRESH" test`** 全绿(含 Task 1 暂缓测试)
+- [ ] **Step 5: Commit** `feat(index): per-repo artifact source plumbing — IndexRepo/SeedRepo/toml/template (#269)`
+
+### Task 3: D3 — 存量 .xlings.json artifact 注入(TDD)
+
+**Files:**
+- Modify: `src/fallback/config_migration.cppm:69-81`
+- Test: `tests/unit/test_config.cpp`
+
+- [ ] **Step 1: 失败单测**
+
+```cpp
+namespace {
+std::string read_all(const std::filesystem::path& p) {
+    std::stringstream ss; ss << std::ifstream(p).rdbuf(); return ss.str();
+}
+}  // namespace
+
+TEST(ConfigIndexMigration, XlingsJsonHealsPrettyLegacyEntry) {
+    auto dir = make_tempdir("mcpp-migrate-xj");
+    auto p = dir / ".xlings.json";
+    { std::ofstream os(p); os << "{\n  \"index_repos\": [\n"
+        "    { \"name\": \"mcpplibs\", \"url\": \"https://github.com/mcpp-community/mcpp-index.git\" }\n"
+        "  ],\n  \"subos\": \"default\",\n  \"mirror\": \"auto\"\n}\n"; }
+    EXPECT_TRUE(mcpp::fallback::migrate_xlings_json_index_names(p));
+    auto text = read_all(p);
+    EXPECT_NE(text.find("\"url\": \"https://github.com/mcpplibs/mcpp-index.git\", "
+        "\"artifact\": \"https://github.com/xlings-res/mcpp-index\""), std::string::npos);
+    EXPECT_NE(text.find("\"subos\": \"default\""), std::string::npos);  // 无关 key 保留
+    EXPECT_EQ(text.find("mcpp-community/mcpp-index"), std::string::npos);
+    EXPECT_FALSE(mcpp::fallback::migrate_xlings_json_index_names(p));   // 幂等
+    std::filesystem::remove_all(dir);
+}
+
+TEST(ConfigIndexMigration, XlingsJsonHealsCompactLegacyNameAndUrl) {
+    auto dir = make_tempdir("mcpp-migrate-xjc");
+    auto p = dir / ".xlings.json";
+    { std::ofstream os(p); os << "{\"index_repos\":[{\"name\":\"mcpp-index\","
+        "\"url\":\"https://github.com/mcpp-community/mcpp-index.git\"}],\"mirror\":\"auto\"}"; }
+    EXPECT_TRUE(mcpp::fallback::migrate_xlings_json_index_names(p));
+    auto text = read_all(p);
+    EXPECT_NE(text.find("\"name\":\"mcpplibs\""), std::string::npos);
+    EXPECT_NE(text.find("\"url\":\"https://github.com/mcpplibs/mcpp-index.git\", "
+        "\"artifact\": \"https://github.com/xlings-res/mcpp-index\""), std::string::npos);
+    EXPECT_FALSE(mcpp::fallback::migrate_xlings_json_index_names(p));
+    std::filesystem::remove_all(dir);
+}
+
+TEST(ConfigIndexMigration, XlingsJsonSkipsInjectionWhenArtifactPresent) {
+    auto dir = make_tempdir("mcpp-migrate-xja");
+    auto p = dir / ".xlings.json";
+    std::string body = "{\n  \"index_repos\": [\n"
+        "    { \"name\": \"mcpplibs\", \"url\": \"https://github.com/mcpplibs/mcpp-index.git\", "
+        "\"artifact\": \"https://github.com/xlings-res/mcpp-index\" }\n  ]\n}\n";
+    { std::ofstream os(p); os << body; }
+    EXPECT_FALSE(mcpp::fallback::migrate_xlings_json_index_names(p));
+    EXPECT_EQ(read_all(p), body);
+    std::filesystem::remove_all(dir);
+}
+```
+
+- [ ] **Step 2: 跑测确认 FAIL**(artifact 未注入)
+- [ ] **Step 3: 实现**(接在 name/URL 替换后):
+
+```cpp
+// Artifact injection (xlings 0.4.68 per-repo artifact source). Idempotency
+// gate: the res base appearing anywhere means a previous run (or a fresh
+// seed) already declared it — plain replace_all would re-inject on every run.
+if (updated.find("xlings-res/mcpp-index") == std::string::npos) {
+    constexpr std::string_view art =
+        ", \"artifact\": \"https://github.com/xlings-res/mcpp-index\"";
+    for (std::string_view urlkv : {
+            "\"url\": \"https://github.com/mcpplibs/mcpp-index.git\"",
+            "\"url\":\"https://github.com/mcpplibs/mcpp-index.git\"" })
+        replace_all(updated, urlkv, std::string(urlkv) + std::string(art));
+}
+```
+
+- [ ] **Step 4: `mcpp build && "$MCPP_FRESH" test`** PASS
+- [ ] **Step 5: Commit** `feat(index): heal existing registry .xlings.json — org URL + artifact injection (#267-A #269)`
+
+### Task 4: D5 — 项目级 [indices] artifact/source + pin 交互
+
+**Files:**
+- Modify: `src/pm/index_spec.cppm:14-23`(加字段 + `artifact_applicable()`)
+- Modify: `src/manifest/toml.cppm:1142-1150`([indices] 长格式读 artifact/source)
+- Modify: `src/config.cppm:546-563`(config.toml [indices] 同步读)+ `ensure_project_index_dir:680-691`(SeedRepo 透传 + 不适用 warn)
+- Test: `tests/unit/test_manifest.cpp`
+
+**Interfaces (produces):**
+```cpp
+// mcpp::pm::IndexSpec 新增
+std::string artifact;   // optional artifact source base (xlings 0.4.68+)
+std::string source;     // optional "auto" | "artifact" | "git"
+bool artifact_applicable() const {   // pin/local forces git — artifact only tracks latest
+    return !artifact.empty() && rev.empty() && tag.empty() && branch.empty() && path.empty();
+}
+```
+
+- [ ] **Step 1: 失败单测**(`test_manifest.cpp`,仿现有 [indices] 解析测试写法;若无现成解析入口测试,则直接测 IndexSpec 语义 + toml 解析函数)
+
+```cpp
+TEST(ManifestIndices, ArtifactAndSourceParsedAndPinSuppresses) {
+    auto m = parse_manifest_from_string(R"(
+[package]
+name = "p"
+version = "0.1.0"
+[indices]
+fast   = { url = "https://example.com/i.git", artifact = "https://example.com/res/i", source = "auto" }
+pinned = { url = "https://example.com/i.git", artifact = "https://example.com/res/i", rev = "abc123" }
+)");  // 按 test_manifest.cpp 现有 helper 名对齐
+    auto& fast = m.indices.at("fast");
+    EXPECT_EQ(fast.artifact, "https://example.com/res/i");
+    EXPECT_EQ(fast.source, "auto");
+    EXPECT_TRUE(fast.artifact_applicable());
+    auto& pinned = m.indices.at("pinned");
+    EXPECT_FALSE(pinned.artifact_applicable());
+}
+```
+
+- [ ] **Step 2: FAIL 确认** → **Step 3: 实现**:两处解析各加两行 `find("artifact")`/`find("source")`;`ensure_project_index_dir` 远程分支:
+
+```cpp
+mcpp::xlings::SeedRepo r{ name, spec.url, "", "" };
+if (spec.artifact_applicable()) { r.artifact = spec.artifact; r.source = spec.source; }
+else if (!spec.artifact.empty())
+    std::println("[warn] index '{}': artifact source ignored (rev/tag/branch/path pins force git)", name);
+customRepos.push_back(std::move(r));
+```
+
+- [ ] **Step 4: 全测 PASS** → **Step 5: Commit** `feat(index): project-level [indices] artifact/source with pin-forces-git rule (#269)`
+
+### Task 5: read_seeded_index_repos 容错锁测
+
+**Files:**
+- Test: `tests/unit/test_pm_package_fetcher.cpp:237` 附近克隆现有 fixture
+
+- [ ] **Step 1: 新测**——entry 含 artifact/source 仍正确提取 name/url:
+
+```cpp
+TEST(PackageFetcher, SeededIndexReposTolerateArtifactFields) {
+    auto project = make_tempdir("mcpp-pf-artifact");   // 对齐该文件现有 temp helper
+    auto xjson = project / ".xlings.json";
+    { std::ofstream os(xjson); os << "{\n  \"index_repos\": [\n"
+        "    { \"name\": \"mcpplibs\", \"url\": \"https://github.com/mcpplibs/mcpp-index.git\", "
+        "\"artifact\": \"https://github.com/xlings-res/mcpp-index\", \"source\": \"auto\" }\n  ]\n}\n"; }
+    auto repos = mcpp::pm::read_seeded_index_repos(xjson);
+    ASSERT_EQ(repos.size(), 1u);
+    EXPECT_EQ(repos[0].first, "mcpplibs");
+    EXPECT_EQ(repos[0].second, "https://github.com/mcpplibs/mcpp-index.git");
+    std::filesystem::remove_all(project);
+}
+```
+(返回类型按现有测试实际形态对齐 —— 以 `:244` 现有断言写法为准。)
+
+- [ ] **Step 2: 跑测**(预期直接 PASS —— 这是回归锁,不是新功能;若 FAIL 则修 `read_seeded_index_repos` 的对象切分)
+- [ ] **Step 3: Commit** `test(pm): lock read_seeded_index_repos tolerance to artifact/source fields`
+
+### Task 6: D4 — xlings pin → 0.4.68 + 常量对齐
+
+**Files:**
+- Modify: `.github/workflows/release.yml`(`:99`、`:284`、`:341-345` 硬编码 0.4.67 全部)、`.github/workflows/cross-build-test.yml:105,218`、`.github/workflows/ci-linux-e2e.yml:126`
+- Modify: `src/xlings.cppm:36`(`kXlingsVersion` "0.4.51"→"0.4.68")
+- Modify: `src/config.cppm` `print_env`(加 `bundled xlings pin   = {kXlingsPinnedVersion}` 行,给常量一个消费点)
+
+- [ ] **Step 1**: `grep -rn '0\.4\.67' .github/workflows/` 逐处替换为 0.4.68(含注释里的版本说明,注释补一句 0.4.68 = per-repo index artifact #377)
+- [ ] **Step 2**: 常量 + print_env;`mcpp build && "$MCPP_FRESH" self env` 目测新行
+- [ ] **Step 3: Commit** `ci: bundled xlings pin 0.4.67 -> 0.4.68 (per-repo index artifact); align kXlingsVersion`
+
+### Task 7: e2e — 151_index_url_artifact_migration.sh
+
+**Files:**
+- Create: `tests/e2e/151_index_url_artifact_migration.sh`(仿 `10_env_command.sh` 的隔离 MCPP_HOME 手法;需 `MCPP_VENDORED_XLINGS` 或系统 xlings,CI bootstrap 已具备)
+
+- [ ] **Step 1: 写脚本**
+
+```bash
+#!/usr/bin/env bash
+# #267/#269: fresh init seeds mcpplibs-org URL + artifact source; legacy
+# config.toml/.xlings.json (old org URL, no artifact) are healed in place,
+# idempotently, in both pretty (mcpp) and compact (xlings) JSON spacings.
+set -e
+TMP=$(mktemp -d); trap "rm -rf $TMP" EXIT
+export MCPP_HOME="$TMP/mcpp-home"
+
+NEW_URL='https://github.com/mcpplibs/mcpp-index.git'
+OLD_URL='https://github.com/mcpp-community/mcpp-index.git'
+ART='https://github.com/xlings-res/mcpp-index'
+CFG="$MCPP_HOME/config.toml"; XJ="$MCPP_HOME/registry/.xlings.json"
+
+# 1. Fresh init: new org URL + artifact in both files.
+"$MCPP" self env > /dev/null
+grep -q "url      = \"$NEW_URL\"" "$CFG"      || { echo "config.toml missing new url"; exit 1; }
+grep -q "artifact = \"$ART\"" "$CFG"          || { echo "config.toml missing artifact"; exit 1; }
+grep -q "\"url\": \"$NEW_URL\", \"artifact\": \"$ART\"" "$XJ" || { echo "seed missing artifact"; exit 1; }
+grep -q 'mcpp-community/mcpp-index' "$CFG" "$XJ" && { echo "old org leaked"; exit 1; }
+
+# 2. Legacy heal (pretty): old URL, no artifact.
+cat > "$CFG" <<EOF
+[xlings]
+binary = "bundled"
+[index]
+default = "mcpplibs"
+[index.repos."mcpplibs"]
+url = "$OLD_URL"
+EOF
+cat > "$XJ" <<EOF
+{
+  "index_repos": [
+    { "name": "mcpplibs", "url": "$OLD_URL" }
+  ],
+  "subos": "default",
+  "lang": "en",
+  "mirror": "auto"
+}
+EOF
+"$MCPP" self env > /dev/null
+grep -q "url = \"$NEW_URL\"" "$CFG"                            || { echo "toml url not healed"; exit 1; }
+grep -q "\"url\": \"$NEW_URL\", \"artifact\": \"$ART\"" "$XJ"  || { echo "xj not healed"; exit 1; }
+grep -q '"subos": "default"' "$XJ"                             || { echo "unrelated key lost"; exit 1; }
+cp "$CFG" "$TMP/cfg1"; cp "$XJ" "$TMP/xj1"
+"$MCPP" self env > /dev/null                                   # idempotent second run
+cmp -s "$CFG" "$TMP/cfg1" && cmp -s "$XJ" "$TMP/xj1"           || { echo "not idempotent"; exit 1; }
+
+# 3. Legacy heal (compact, old name): xlings-writer spacing.
+printf '{"index_repos":[{"name":"mcpp-index","url":"%s"}],"mirror":"auto"}' "$OLD_URL" > "$XJ"
+"$MCPP" self env > /dev/null
+grep -q '"name":"mcpplibs"' "$XJ"        || { echo "compact name not healed"; exit 1; }
+grep -q "xlings-res/mcpp-index" "$XJ"    || { echo "compact artifact not injected"; exit 1; }
+grep -q 'mcpp-community' "$XJ" && { echo "compact old org left"; exit 1; }
+
+echo "OK"
+```
+
+- [ ] **Step 2: 本地跑** `MCPP="$MCPP_FRESH" bash tests/e2e/151_index_url_artifact_migration.sh` → OK
+- [ ] **Step 3: Commit** `test(e2e): 151 — index org URL heal + artifact seed/injection`
+
+### Task 8: 版本 0.0.103 + CHANGELOG
+
+- [ ] `mcpp.toml:3` version → `0.0.103`;`src/toolchain/fingerprint.cppm:21` → `0.0.103`(同 commit!)
+- [ ] CHANGELOG.md 顶部加 0.0.103 条目(#267 URL 迁移 + 存量治愈、#269 artifact 采纳 + pin 0.4.68、[indices] artifact)
+- [ ] Commit `release: 0.0.103 — index org migration + per-repo artifact adoption (#267 #269)`
+
+### Task 9: 验证 + PR + CI + 合入
+
+- [ ] `mcpp build && "$MCPP_FRESH" test` 全绿;e2e 相关子集(10、151)绿;可选跑本机 e2e 基线抽样
+- [ ] `git push -u origin feat/index-artifact-0.0.103`;`gh pr create`(标题 `feat(index): mcpplibs org migration + xlings 0.4.68 per-repo artifact adoption — 0.0.103 (#267 #269)`,body 引两 issue + 设计文档)
+- [ ] 等 CI 全绿(ci-linux、ci-linux-e2e 两 shard、cross-build-test、windows/macos e2e、fresh-install)
+- [ ] `gh pr merge <n> --squash --admin`(不加 `--delete-branch` 以防叠栈坑;单 PR 无叠栈,可加)
+
+### Task 10: 发布 + xlings 全生态验证(runbook = release-publish-pipeline 记忆 + .agents/skills/mcpp-release)
+
+- [ ] `gh workflow run release.yml --ref main`(从 mcpp.toml 派生 v0.0.103;publish-ecosystem 自动镜像 xlings-res/mcpp 双端 + 开 xim-pkgindex bump PR)
+- [ ] 双端 GET 核验四平台资产(`curl -sL -o /dev/null -w '%{http_code} %{size_download}'`,GitHub + gitcode.com 直链主机,必须 200 + 真字节;HEAD 不可信)
+- [ ] `gh pr merge <bump-pr> --repo openxlings/xim-pkgindex --squash --admin`(publish-artifact.yml 自动发索引)
+- [ ] 实机验证:`xlings update && xlings install mcpp@0.0.103 -y` → `mcpp --version` = 0.0.103
+- [ ] **artifact 路径专项**(本 PR 主功能):fresh MCPP_HOME + xlings ≥0.4.68 捆绑,`mcpp index update` → `registry/data/mcpplibs` 变 artifact 管理(`.git` 消失、`.xlings-index-version` 出现);`registry/.xlings.json` mcpplibs 条目带 artifact 字段
+- [ ] 收尾 pin:工作区 `.xlings.json` bootstrap pin → 0.0.103 直推 main(`ci: workspace mcpp bootstrap pin -> 0.0.103 (released + indexed)`);`ci-fresh-install.yml` 的 0.0.102 pin 同步 bump
+
+## Self-Review 结论
+
+- 设计文档 D1–D5 全覆盖(D1→T1,D2→T2,D3→T3,D5→T4,兼容锁→T5,D4→T6,e2e→T7);P5(CN region 对象)按设计文档明确推迟,非本计划范围。
+- 类型一致性:`SeedRepo{name,url,artifact,source}` 贯穿 T2/T4;`IndexRepo` 同形;`artifact_applicable()` 只在 T4 定义与使用。
+- 已知风险:test_manifest.cpp 的解析 helper 名需现场对齐(计划内已标注);`ensure_project_index_dir` 的 `spec.is_builtin()` 分支(mcpplibs)不进 customRepos,不受 T4 影响。
diff --git a/.agents/docs/2026-07-22-issue267-269-index-artifact-and-org-migration-design.md b/.agents/docs/2026-07-22-issue267-269-index-artifact-and-org-migration-design.md
new file mode 100644
index 00000000..fb9ae685
--- /dev/null
+++ b/.agents/docs/2026-07-22-issue267-269-index-artifact-and-org-migration-design.md
@@ -0,0 +1,316 @@
+# 索引组织迁移 + 采纳 xlings 0.4.68 per-repo artifact 来源 — 设计方案
+
+**日期**: 2026-07-22
+**关联**: mcpp#267(索引 URL 指向已迁移旧组织 + 被判定自定义索引强制走 git)、
+mcpp#269(采纳 xlings 0.4.68 per-repo artifact)、
+openxlings/xlings#377(功能实现,PR #379)、#378(compact::git CA 探测)、#380(shim env 去重)
+**上游设计文档**: xlings 仓 `.agents/docs/2026-07-22-issue377-custom-index-artifact-design.md`
+**上游 schema**: xlings 仓 `docs/spec/xlings-json-schema.md`(0.4.68+ `artifact` / `source` 字段)
+
+---
+
+## 一、问题陈述
+
+两个 issue 收敛为同一条主线:**mcpplibs 索引的同步路径健壮化**,外加一个正确性前提(URL 组织迁移)。
+
+### #267-A:索引 URL 仍指向已迁移的旧组织(正确性,可独立修)
+
+索引仓库已从 `mcpp-community/mcpp-index` 迁到 `mcpplibs/mcpp-index`(工具仓库
+`mcpp-community/mcpp` 未迁移)。mcpp 目前**完全靠 GitHub 仓库重定向**才能工作,
+该依赖脆弱:旧名一旦被再次占用即静默指向错误内容;部分镜像/代理不跟随重定向。
+
+### #267-B / #269:索引同步硬依赖 git → 采纳 artifact 路径
+
+xlings 0.4.68 前,自定义 `index_repos`(mcpplibs 即是)恒走 git
+(`repo.cppm` 准入三分支全要求 `isDefaultOfficial`),拿不到官方索引 artifact 路径的
+adaptive mirror reorder + stall watchdog。实测症状:同一次 `mcpp index update` 里
+主索引 artifact 成功、mcpplibs git 因宿主 CA 路径问题失败。
+
+xlings 0.4.68(#377/#379)已落地:任何 `index_repos` 条目可声明 `artifact` 来源,
+`source: auto`(默认)下 artifact 优先、git 自动回退。**发布端零改动**——
+`xlings-res/mcpp-index` 现有布局(仓根 `mcpp-index-pointers.json` + `v<sha>` release +
+`mcpp-index-<sha>.tar.gz`)与 xlings 消费端已实测逐字节兼容(v2e23e20:sha256 一致、
+sole-entry key 兜底覆盖 `mcpp` ≠ `mcpplibs` 命名差异)。
+
+mcpp 侧要做的只是:**声明 + 透传 + 治愈存量 + 升 pin**。
+
+---
+
+## 二、现状盘点(涉改位置)
+
+### 代码(旧 URL 硬编码 4 处)
+
+| 位置 | 作用 |
+|---|---|
+| `src/config.cppm:360` | `write_default_config_toml` 模板 `[index.repos."mcpplibs"] url` |
+| `src/config.cppm:407` | `canonicalize_legacy_index_names` 名字迁移分支的旧 URL 联合条件 |
+| `src/config.cppm:575` | `add_default("mcpplibs", <旧URL>)` 内存级默认 |
+| `src/publish/pipeline.cppm:158` | `mcpp publish` 打印给用户的 Fork 地址 |
+
+### 数据流(artifact 字段要穿过的层)
+
+```
+config.toml [index.repos."mcpplibs"]          ← 模板 + TOML 解析(config.cppm:535-543,现只读 url)
+        │
+        ▼
+IndexRepo { name, url }                        ← src/config.cppm:36,需扩字段
+        │
+        ▼
+seed_xlings_json(span<pair<name,url>>)         ← src/xlings.cppm:250/1110,pair 表达不了新字段
+        │
+        ▼
+registry/.xlings.json "index_repos"            ← xlings 0.4.68 消费 artifact/source
+        │(仅在缺失时 seed;存量安装走 migrate_xlings_json_index_names,config.cppm:581-586)
+        ▼
+xlings sync(0.4.68:artifact 优先 + git 回退)
+```
+
+另有两个旁路消费者,改动时必须不破坏:
+
+- `src/pm/package_fetcher.cppm:252-300` — 手写解析 `.xlings.json` 的 `index_repos`
+  (按 key 容错读 name/url,多余字段应天然无害,需单测锁住);
+- 项目级 `ensure_project_index_dir`(`src/config.cppm:671-714`)— 从 `IndexSpec`
+  构造 `customRepos` pair 后 seed 项目 `.mcpp/.xlings.json`。
+
+### 迁移钩子(现成的,扩展即可)
+
+| 钩子 | 位置 | 现状 |
+|---|---|---|
+| `migrate_config_toml_index_names` | `src/fallback/config_migration.cppm:55` | 文本替换 `mcpp-index`→`mcpplibs`(名字) |
+| `migrate_xlings_json_index_names` | `src/fallback/config_migration.cppm:69` | 同上,针对 `.xlings.json` 的 `"name"` 字段 |
+| `canonicalize_legacy_index_names` | `src/config.cppm:400` | 内存级名字迁移 + 去重 |
+
+### 版本 pin
+
+- CI:`release.yml:99/281-345`、`cross-build-test.yml:105/218`、`ci-linux-e2e.yml:126`
+  全部 `0.4.67`;
+- 代码常量:`src/xlings.cppm:36` `pinned::kXlingsVersion = "0.4.51"` —— **已陈旧**,
+  仅被 `config.cppm:34` 的 `kXlingsPinnedVersion` re-export,且后者无任何消费点
+  (捆绑 xlings 实际来自 release bundle / `MCPP_VENDORED_XLINGS` / 系统 PATH,
+  见 `src/fallback/xlings_binary.cppm`)。本次一并对齐,消除"版本常量双源"旧债
+  (0.0.93 批次教训)。
+
+### 文档(非阻塞,顺带)
+
+`docs/00-getting-started.md:98`、`docs/04-build-from-source.md:96` 及 zh 对应文件
+仍链接 `mcpp-community/mcpp-index`。
+
+---
+
+## 三、设计
+
+**核心理念:默认值与治愈逻辑都收敛在代码常量一处;文件层迁移只做最小文本手术。**
+新 URL 与 artifact base 定义为单一常量对,所有消费点(模板、add_default、canonicalize、
+迁移、publish 提示)引用它,不再各写一份字面量(避免下次迁移再来一遍 4 处 grep)。
+
+```cpp
+// src/config.cppm(或独立常量区)
+inline constexpr std::string_view kMcpplibsUrl      = "https://github.com/mcpplibs/mcpp-index.git";
+inline constexpr std::string_view kMcpplibsUrlLegacy= "https://github.com/mcpp-community/mcpp-index.git";
+inline constexpr std::string_view kMcpplibsArtifact = "https://github.com/xlings-res/mcpp-index";
+```
+
+### D1. URL 组织迁移(#267-A,可独立发)
+
+1. **4 处硬编码**全部改为新 URL(经上面常量)。
+2. **`canonicalize_legacy_index_names` 扩展**(`config.cppm:400`)——顺序陷阱是
+   issue 里点名的坑:现有名字分支条件是 `name=="mcpp-index" && url==<旧URL>`,
+   若先重写 URL 再进名字分支,老配置就匹配不上了。**先 URL 归一、名字分支只看 name**
+   (归一后 URL 恒为新值,url 条件不再有区分意义;原 url 条件本意是避免误伤同名
+   自定义仓,归一后改为接受新旧两个官方 URL 即等价):
+
+   ```cpp
+   for (auto r : cfg.indexRepos) {
+       if (r.url == kMcpplibsUrlLegacy) r.url = kMcpplibsUrl;          // ① 组织迁移
+       if (r.name == "mcpp-index" && r.url == kMcpplibsUrl) r.name = "mcpplibs"; // ② 名字迁移
+       // ③ 去重逻辑不变 —— URL 归一后,"老条目+新默认条目"并存会在此折叠成一条
+   }
+   ```
+
+   注意去重是 `name+url` 联合判等:URL 归一必须发生在去重**之前**,否则
+   `mcpplibs@旧URL` 与 `mcpplibs@新URL` 会被当成两个仓保留。现在的单循环结构
+   天然满足(逐条归一后再查重),保持即可。
+3. **`migrate_config_toml_index_names` 扩展**(文本层,治愈磁盘上的 config.toml):
+   增加 `replace_all(updated, 旧URL, 新URL)`。幂等:替换后源串不再出现。
+4. **`migrate_xlings_json_index_names` 扩展**(治愈 registry `.xlings.json`
+   ——存量安装只走 migrate 不走 seed,见 `config.cppm:582-586`):同样
+   `replace_all` 旧 URL→新 URL(带/不带空格两种 JSON 间距变体,与现有 name
+   替换的双变体写法一致)。
+5. `publish/pipeline.cppm:158` Fork 地址、docs 4 处链接改新 org。
+
+### D2. IndexRepo/seed 管线支持 artifact(#269 主体)
+
+1. **`IndexRepo` 扩字段**(`config.cppm:36`):
+
+   ```cpp
+   struct IndexRepo {
+       std::string name;
+       std::string url;
+       std::string artifact;   // 可选:artifact 来源 base(空 = 未声明,纯 git)
+       std::string source;     // 可选:"auto"|"artifact"|"git"(空 = 不发射,xlings 默认 auto)
+   };
+   ```
+
+   本轮 `artifact` 只支持 string 形态;xlings 侧的 region 对象
+   `{"GLOBAL":..,"CN":..}` 留待 CN 镜像仓实际部署后再扩(见 §六)。
+
+2. **TOML 解析**(`config.cppm:535-543`):`[index.repos.NAME]` 增读 `artifact`、
+   `source` 两个可选 string key。旧 mcpp 二进制读新 config.toml 时因只查 `url`
+   而自然忽略新 key,向后安全。
+
+3. **`seed_xlings_json` 签名升级**(`src/xlings.cppm:250/1110`):
+   `span<const pair<string,string>>` 表达不了新字段。在 `mcpp::xlings` 内新增轻量
+   结构(保持该模块不依赖 `mcpp.config`):
+
+   ```cpp
+   struct SeedRepo {
+       std::string name, url, artifact, source;
+   };
+   void seed_xlings_json(const Env&, std::span<const SeedRepo>, ...);
+   ```
+
+   发射逻辑:`artifact` 非空才写 `"artifact"` key;`source` 非空才写 `"source"` key
+   ——未声明的仓输出逐字节不变,与 xlings 侧"未声明 = 纯 git 旧行为"对齐。
+   两个调用方(`write_default_xlings_json`、`ensure_project_index_dir`)同步改为
+   构造 `SeedRepo`。旧签名直接删除(内部 API,无兼容负担)。
+
+4. **默认配置模板**(`config.cppm:359-361`):
+
+   ```toml
+   [index.repos."mcpplibs"]
+   url      = "https://github.com/mcpplibs/mcpp-index.git"
+   artifact = "https://github.com/xlings-res/mcpp-index"
+   # source = "auto"  # 默认:artifact 优先,git 回退;可改 "git" 强制走 git
+   ```
+
+5. **`add_default` 对齐**(`config.cppm:571-575`):默认条目带 artifact。另在
+   `canonicalize_legacy_index_names` 末尾补一条**内存级治愈**:凡 `url == kMcpplibsUrl`
+   且 `artifact` 为空且用户未显式 `source = "git"` 的条目,填充默认 artifact。
+   这样即使用户的 config.toml 是旧模板(没有 artifact 行),每次运行也拿到
+   artifact 声明——**config.toml 不做 artifact 注入的文本手术**(用户可编辑文件,
+   注入易碎且没必要;代码级默认已覆盖)。用户想退出 artifact 路径的显式出口就是
+   `source = "git"`。
+
+6. **`print_env`**(`config.cppm:663-668`)顺带打印 artifact 标记,便于 doctor 场景确认。
+
+### D3. 存量 registry `.xlings.json` 的 artifact 注入(#269 建议 2)
+
+registry `.xlings.json` 只在缺失时 seed,存量安装唯一的治愈通道是
+`migrate_xlings_json_index_names`。扩展它(改名为语义更准的
+`migrate_xlings_json_index_entries`,或保名加逻辑,倾向后者少动调用点):
+
+```
+若 文本含 "xlings-res/mcpp-index"            → 已注入,跳过(幂等闸)
+否则 对 "url": "<新URL>" 与 "url":"<新URL>" 两种间距变体:
+    replace_all(..., "\"url\": \"<新URL>\"",
+                     "\"url\": \"<新URL>\", \"artifact\": \"<res base>\"")
+```
+
+顺序上依赖 D1-4 已先把旧 URL 归一为新 URL(同一次 migrate 调用内先 URL 后 artifact),
+故只需匹配新 URL。幂等性由"已含 res base 即跳过"保证——这是必须的:
+纯 `replace_all` 二次运行会重复注入,替换后的文本仍包含原匹配串。
+
+文本手术的安全性论证:该文件由两个写者维护——mcpp 的 `seed_xlings_json`
+(pretty,`"key": "value"`)与 xlings 自身的序列化器(compact 可能无空格),
+双变体替换覆盖两者;URL 串带 `/` 不会出现在其它 value 里(项目级 `.xlings.json`
+不经此迁移,只有 registry 的走这条路)。**不整文件重生成**——文件里有 xlings 的
+subos/版本绑定状态,重生成会丢(0.0.9x 批次已确立的原则)。
+
+旧 xlings(<0.4.68)读到 `artifact`/`source` 字段安全忽略(上游实测),
+所以注入不需要先确认捆绑 xlings 版本,与 D4 无顺序耦合。
+
+### D4. 捆绑 xlings pin → 0.4.68
+
+- `release.yml`(x86_64 两处 + aarch64 硬编码 `0.4.67` 两处)、
+  `cross-build-test.yml` ×2、`ci-linux-e2e.yml` quick_install 参数,全部 → `0.4.68`;
+- `src/xlings.cppm:36` `kXlingsVersion` `"0.4.51"` → `"0.4.68"`,并给
+  `config.cppm:34` 的无消费 re-export 补个用途或删除(倾向:doctor 输出里打印
+  "bundled xlings pinned: X",让常量有单一消费点,防再度失同步);
+- 低于 0.4.68 的 xlings 忽略 artifact 字段、行为不变,所以 pin 升级只是"吃到收益"
+  的开关,不是正确性前提——**D1–D3 可以先合,D4 跟随下一次 release 节奏**。
+
+### D5.(可选,#269 建议 4)项目级 `[indices]` artifact
+
+`IndexSpec`(`src/pm/index_spec.cppm:14`)增加 `std::string artifact; std::string source;`,
+mcpp.toml `[indices]` 长格式与 `config.toml [indices]`(`config.cppm:546-563`)同步增读,
+`ensure_project_index_dir` 构造 `SeedRepo` 时透传。
+
+**与 pin 的交互是这里唯一的设计点**:`rev`/`tag`/`branch` 锁定的索引,artifact 通道
+只跟 latest pointer,无法表达任意 rev。规则:**凡 `rev`/`tag`/`branch` 任一非空,
+不发射 artifact 字段**(等效强制 git),并在解析时对"pin + artifact 并存"给一条
+warn,说明 artifact 被忽略。本地 `path` 索引同理天然不发射。
+
+此项不阻塞主线,可作为同批次的独立 commit 或推迟。
+
+---
+
+## 四、兼容性矩阵
+
+| 组合 | 行为 |
+|---|---|
+| 新 mcpp + xlings ≥0.4.68 | artifact 优先,git 回退(完整收益) |
+| 新 mcpp + xlings <0.4.68 | artifact 字段被忽略,纯 git,行为同今天(仅吃不到收益,不出错) |
+| 旧 mcpp + 新 config.toml | TOML 解析只读 url,忽略 artifact/source 行,正常 |
+| 旧 mcpp + 已注入 artifact 的 .xlings.json | `package_fetcher` 手写 parser 按 key 读 name/url,多余字段无害(单测锁) |
+| 用户显式 `source = "git"` | 透传后 xlings 强制 git,且 D2-5 的内存级 artifact 填充跳过 |
+| 旧 URL 仅存于用户自定义条目(name ≠ mcpplibs/mcpp-index)| URL 归一按 url 匹配不看 name,同样治愈(它就是官方仓的别名条目) |
+
+风险点与对策:
+
+- **`package_fetcher.cppm` 手写 JSON parser**:entry 对象内新增 key 后,其
+  按-brace 切分/按-key 提取逻辑必须仍取对 name/url。加一条含 artifact 字段的
+  fixture 单测。
+- **文本迁移的双写者间距**:双变体 `replace_all` + "已含 res base"幂等闸,
+  且 unit test 覆盖 mcpp-pretty 与 xlings-compact 两种输入。
+- **GitHub 重定向窗口期**:D1 合入前旧 URL 一直可用(靠重定向),合入后新旧 URL
+  都直连有效,无停机窗口。
+
+---
+
+## 五、测试计划
+
+单测(`tests/unit`):
+
+1. `canonicalize_legacy_index_names`:旧 URL+旧名 → 新 URL+`mcpplibs`;
+   旧 URL+新名;新 URL 无 artifact → 填默认 artifact;`source="git"` 不填;
+   老条目与默认条目 URL 归一后折叠为一条(去重顺序回归)。
+2. `migrate_config_toml_index_names`:旧模板文本 → URL 替换,幂等(跑两遍字节相同)。
+3. `migrate_xlings_json_index_names`:pretty/compact 两种输入 × {旧URL, 新URL无artifact,
+   已注入} 矩阵,幂等,subos/envs 等无关 key 逐字节保留。
+4. `seed_xlings_json`:带/不带 artifact/source 的发射形态;无 artifact 条目输出与
+   现行为逐字节一致(零 diff 门,沿用 CommandDialect 批次的做法)。
+5. `package_fetcher` index_repos parser:含 artifact 字段的 entry 仍正确提取 name/url。
+
+e2e(`tests/e2e`):
+
+6. fresh init:生成的 config.toml 与 registry `.xlings.json` 含新 URL + artifact 字段。
+7. 存量升级模拟:预置旧 URL、无 artifact 的 config.toml + `.xlings.json`(pretty 与
+   compact 各一),跑任一命令后两文件被治愈,再跑一遍无变化。
+
+实机验证(release 前,沿用发布闭环流程):Ubuntu 宿主(可复现 `/etc/ssl/cert.pem`
+缺失环境更佳)fresh install → `mcpp index update` → 确认 `data/mcpplibs` 迁为
+artifact 管理(`.git` 消失、`.xlings-index-version` 出现)且 git 不可用时同步仍成功
+——issue #269 已实测过该路径,e2e 复核即可。
+
+---
+
+## 六、落地顺序
+
+| 阶段 | 内容 | 依赖 |
+|---|---|---|
+| P1 | D1 URL 迁移(4 处 + 三个迁移钩子 + docs) | 无,可立即发 |
+| P2 | D2 管线扩展 + D3 存量注入(同一 PR,D3 依赖 D1 的 URL 归一先行于同一次 migrate) | P1 |
+| P3 | D4 pin → 0.4.68(CI + 常量对齐) | 随下一次 release |
+| P4 | D5 项目级 `[indices]` artifact(可选) | P2 |
+| P5 | CN region 对象:gitcode.com/xlings-res/mcpp-index 镜像仓部署后(mirror_res.sh 基建已有),`kMcpplibsArtifact` 升级为 region 对象发射,`SeedRepo.artifact` 相应扩为 GLOBAL/CN 两值 | P2 + 镜像仓就绪 |
+
+P1+P2+P3 目标合入同一个版本(0.0.103),单 PR 分 commit 或两个小 PR 均可;
+P5 留待 CN 镜像仓真实存在后再动,避免声明一个 404 的 base(xlings auto 模式下
+artifact 失败会回退 git,不至于坏,但会白付一次探测)。
+
+## 七、非目标
+
+- 不改 xlings 侧任何代码(0.4.68 已全部就绪);
+- 不改 mcpp-index / xlings-res 发布端(实测逐字节兼容,零改动);
+- 不做 config.toml 的 artifact 文本注入(代码级默认覆盖,见 D2-5);
+- `artifact` 的 region 对象形态本轮不进 TOML schema(P5 再扩)。
diff --git a/.github/workflows/ci-linux-e2e.yml b/.github/workflows/ci-linux-e2e.yml
index f60d9a1e..0cc37bac 100644
--- a/.github/workflows/ci-linux-e2e.yml
+++ b/.github/workflows/ci-linux-e2e.yml
@@ -123,7 +123,7 @@ jobs:
 
       - name: Bootstrap xlings + released mcpp
         run: |
-          curl -fsSL https://raw.githubusercontent.com/openxlings/xlings/main/tools/other/quick_install.sh | bash -s v0.4.67
+          curl -fsSL https://raw.githubusercontent.com/openxlings/xlings/main/tools/other/quick_install.sh | bash -s v0.4.68
           export PATH="$HOME/.xlings/subos/current/bin:$PATH"
           xlings update
           xlings install mcpp -y -g
diff --git a/.github/workflows/cross-build-test.yml b/.github/workflows/cross-build-test.yml
index f24d7f70..92bb3ec6 100644
--- a/.github/workflows/cross-build-test.yml
+++ b/.github/workflows/cross-build-test.yml
@@ -92,17 +92,17 @@ jobs:
       - name: Bootstrap mcpp via xlings
         env:
           XLINGS_NON_INTERACTIVE: '1'
-          # 0.4.67 (current) — kept in lock-step with the xlings the release
-          # is built/bundled against (release.yml). Bumped 0.4.62 -> 0.4.67 for
-          # mcpp#238: xlings 0.4.67 carries the multi-index_repo install fix
-          # (openxlings/xlings#374, commit cf9b60d5) so a workspace member with
-          # >=2 inherited index_repos installs uncached packages instead of
-          # failing silently. A past 0.4.61 "download 404
+          # 0.4.68 (current) — kept in lock-step with the xlings the release
+          # is built/bundled against (release.yml). 0.4.67 carried the
+          # multi-index_repo install fix (openxlings/xlings#374); 0.4.68 adds
+          # per-repo index artifact sources (openxlings/xlings#377) so the
+          # mcpplibs index syncs via artifact with git as fallback (mcpp#269).
+          # A past 0.4.61 "download 404
           # for mcpp@<pin>" was NOT a version bug — the xlings-res/mcpp GitHub
           # release assets were uploaded in a broken state (records present,
           # blobs missing → 404 on GET); re-uploaded clean. The stale-INDEX
           # half is handled by the marker-clear below.
-          XLINGS_VERSION: '0.4.67'
+          XLINGS_VERSION: '0.4.68'
         run: |
           tarball="xlings-${XLINGS_VERSION}-linux-x86_64.tar.gz"
           curl -fsSL -o "/tmp/${tarball}" \
@@ -215,7 +215,7 @@ jobs:
       - name: Bootstrap mcpp via xlings
         env:
           XLINGS_NON_INTERACTIVE: '1'
-          XLINGS_VERSION: '0.4.67'
+          XLINGS_VERSION: '0.4.68'
         run: |
           tarball="xlings-${XLINGS_VERSION}-linux-x86_64.tar.gz"
           curl -fsSL -o "/tmp/${tarball}" \
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 9d2a4886..6ff6a9a3 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -96,7 +96,7 @@ jobs:
           # Pin xlings to a known-good version. The upstream install
           # script always grabs `latest` (no version override), so we
           # download + self-install manually to avoid broken releases.
-          XLINGS_VERSION: '0.4.67'
+          XLINGS_VERSION: '0.4.68'
         run: |
           if [ ! -x "$HOME/.xlings/subos/default/bin/xlings" ]; then
             tarball="xlings-${XLINGS_VERSION}-linux-x86_64.tar.gz"
@@ -278,10 +278,10 @@ jobs:
           echo "version=$VERSION" >> "$GITHUB_OUTPUT"
           echo "tag=v$VERSION"    >> "$GITHUB_OUTPUT"
 
-      - name: Bootstrap mcpp via xlings (latest 0.4.67)
+      - name: Bootstrap mcpp via xlings (latest 0.4.68)
         env:
           XLINGS_NON_INTERACTIVE: '1'
-          XLINGS_VERSION: '0.4.67'
+          XLINGS_VERSION: '0.4.68'
         run: |
           tarball="xlings-${XLINGS_VERSION}-linux-x86_64.tar.gz"
           curl -fsSL -o "/tmp/${tarball}" \
@@ -336,13 +336,13 @@ jobs:
           exec "$(dirname "$0")/bin/mcpp" "$@"
           LAUNCHER
           chmod +x "$STAGING/$WRAPPER/mcpp"
-          # Bundle the aarch64 xlings (0.4.67) so install.sh consumers on aarch64
+          # Bundle the aarch64 xlings (0.4.68) so install.sh consumers on aarch64
           # get an aarch64 xlings, not the x86_64 bootstrap one.
-          XLA="xlings-0.4.67-linux-aarch64.tar.gz"
+          XLA="xlings-0.4.68-linux-aarch64.tar.gz"
           if curl -fsSL -o "/tmp/$XLA" \
-               "https://github.com/openxlings/xlings/releases/download/v0.4.67/$XLA"; then
+               "https://github.com/openxlings/xlings/releases/download/v0.4.68/$XLA"; then
             tar -xzf "/tmp/$XLA" -C /tmp
-            XLBIN=$(find /tmp/xlings-0.4.67-linux-aarch64 -path '*/bin/xlings' -type f | head -1)
+            XLBIN=$(find /tmp/xlings-0.4.68-linux-aarch64 -path '*/bin/xlings' -type f | head -1)
             if [ -n "$XLBIN" ]; then
               mkdir -p "$STAGING/$WRAPPER/registry/bin"
               cp "$XLBIN" "$STAGING/$WRAPPER/registry/bin/xlings"
@@ -417,7 +417,7 @@ jobs:
       - name: Bootstrap mcpp via xlings
         env:
           XLINGS_NON_INTERACTIVE: '1'
-          XLINGS_VERSION: '0.4.67'
+          XLINGS_VERSION: '0.4.68'
         run: |
           if [ ! -x "$HOME/.xlings/subos/default/bin/xlings" ]; then
             WORK=$(mktemp -d)
@@ -599,7 +599,7 @@ jobs:
         shell: bash
         env:
           XLINGS_NON_INTERACTIVE: '1'
-          XLINGS_VERSION: '0.4.67'
+          XLINGS_VERSION: '0.4.68'
         run: |
           WORK=$(mktemp -d)
           zipfile="xlings-${XLINGS_VERSION}-windows-x86_64.zip"
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c6d499cf..aff36192 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,25 @@
 > 本文件追踪 `mcpp-community/mcpp` 公开仓的版本演进。
 > 格式参考 [Keep a Changelog](https://keepachangelog.com/zh-CN/1.1.0/)。
 
+## [0.0.103] — 2026-07-22
+
+> #267/#269:索引侧健壮化一批——mcpplibs 索引 URL 组织迁移(不再依赖 GitHub 重定向)+ 采纳 xlings 0.4.68 per-repo artifact 来源(索引同步不再硬依赖可用的 git)。设计见 `.agents/docs/2026-07-22-issue267-269-index-artifact-and-org-migration-design.md`。
+
+### 修复
+
+- **mcpplibs 索引 URL 仍指向已迁移的旧组织**(#267-A):索引仓已迁 `mcpplibs/mcpp-index`,mcpp 4 处硬编码旧 `mcpp-community` URL 全靠 GitHub 仓库重定向才能工作——旧名一旦被再次占用即静默指向错误内容。新/旧 URL 与 artifact base 收敛为 `mcpp::config` 三常量;`canonicalize_legacy_index_names` 导出并承担"URL 归一→名字迁移→artifact 填充→去重"单循环(**URL 归一先行**,老配置的名字迁移仍命中、新旧条目在去重处折叠);存量安装经既有文本迁移钩子治愈(config.toml 与 registry `.xlings.json` 的 URL 就地替换),publish Fork 提示与 docs 链接同步。
+
+### 新增
+
+- **采纳 xlings 0.4.68 per-repo artifact 来源**(#269,#267-B):默认 `mcpplibs` 条目(config.toml 模板 + 内存级默认)声明 `artifact = xlings-res/mcpp-index`,`source = "git"` 为显式退出口;seed 管线由 `(name,url)` pair 升级为 `SeedRepo{name,url,artifact,source}`,非空才发射——无 artifact 的仓输出逐字节不变(测试锁定)。存量 registry `.xlings.json` 唯一治愈通道是文本迁移:URL 归一后就地注入 artifact 字段,幂等闸=res base 已出现即跳过,双间距变体覆盖 mcpp/xlings 两个写者,`subos`/版本绑定等无关状态逐字节保留(**不整文件重生成**)。旧 xlings(<0.4.68)安全忽略新字段,发布端 `xlings-res/mcpp-index` 布局实测零改动。
+- **项目级 `[indices]` artifact/source**(#269 可选项):`IndexSpec` 增两字段,mcpp.toml 与 config.toml `[indices]` 长格式同步解析,经项目 seed 透传;`artifact_applicable()` 编码设计规则——**rev/tag/branch pin(及本地 path)强制 git**(artifact 通道只跟 latest pointer),声明了 artifact 但不适用时告警而非静默同步错误版本。
+- **捆绑 xlings pin 0.4.67 → 0.4.68**(release/cross-build/e2e 三 workflow):0.4.68 携 openxlings/xlings#377(自定义 index artifact)/#380(shim env 去重)。陈旧无消费的 `kXlingsVersion`(0.4.51)对齐至 0.4.68 并由 `mcpp self env` 打印,常量不再能静默漂移。
+
+### 备注
+
+- e2e 新增 151:fresh init 播种新 URL + artifact;老 org URL/无 artifact 的存量 config.toml 与 `.xlings.json`(pretty/compact 双间距)就地治愈且幂等,无关 `.xlings.json` 状态保留。
+- CN region 对象形态(`{"GLOBAL":..,"CN":..}`)待 gitcode 侧 `xlings-res/mcpp-index` 镜像仓真实部署后再扩(设计文档 P5),避免声明 404 base 白付探测。
+
 ## [0.0.102] — 2026-07-22
 
 > 四条 issue 一个批次:#261 windows 命令行长度、#257 clang 依赖跟踪缺口、#258 条件段表达力、#254 host/target 双轴不自洽。贯穿主线是**同一决策不许两处推导**,以及本批次新立的第二条不变量**失败必须响,不许静默降级**。设计见 `.agents/docs/2026-07-22-v0.0.102-batch-254-261-design.md`,issue 裁决见 `.agents/docs/2026-07-22-issue-triage-254-261.md`。
diff --git a/docs/00-getting-started.md b/docs/00-getting-started.md
index 5525a1ae..98b145b9 100644
--- a/docs/00-getting-started.md
+++ b/docs/00-getting-started.md
@@ -95,7 +95,7 @@ Declare dependencies in `mcpp.toml`:
 ```
 
 `mcpp build` automatically resolves SemVer constraints against the
-[mcpp-index](https://github.com/mcpp-community/mcpp-index), fetches the source,
+[mcpp-index](https://github.com/mcpplibs/mcpp-index), fetches the source,
 and adds it to the build graph. For a complete example, see `02-with-deps` in
 [01 — Examples](01-examples.md).
 
diff --git a/docs/04-build-from-source.md b/docs/04-build-from-source.md
index 8fd2e06d..3d88d7e8 100644
--- a/docs/04-build-from-source.md
+++ b/docs/04-build-from-source.md
@@ -93,5 +93,5 @@ mcpp is in early iteration and its interfaces may change. Before submitting a PR
 
 - [Community forum](https://forum.d2learn.org/category/20)
 - Chat group QQ: 1067245099
-- [mcpp-index](https://github.com/mcpp-community/mcpp-index) — the default package index
+- [mcpp-index](https://github.com/mcpplibs/mcpp-index) — the default package index
 - [mcpplibs](https://github.com/mcpplibs) — the companion collection of modular C++ libraries
diff --git a/docs/zh/00-getting-started.md b/docs/zh/00-getting-started.md
index 34490dd7..0cb77ab2 100644
--- a/docs/zh/00-getting-started.md
+++ b/docs/zh/00-getting-started.md
@@ -96,7 +96,7 @@ mcpp test               # 编译并运行 tests/**/*.cpp(gtest 风格)
 ```
 
 `mcpp build` 将自动从
-[mcpp-index](https://github.com/mcpp-community/mcpp-index) 解析 SemVer
+[mcpp-index](https://github.com/mcpplibs/mcpp-index) 解析 SemVer
 约束、拉取源码并加入编译图。完整示例参见
 [01 — 示例项目](01-examples.md) 中的 `02-with-deps`。
 
diff --git a/docs/zh/04-build-from-source.md b/docs/zh/04-build-from-source.md
index 56f35957..5f011228 100644
--- a/docs/zh/04-build-from-source.md
+++ b/docs/zh/04-build-from-source.md
@@ -100,5 +100,5 @@ mcpp 处于早期迭代阶段,接口可能调整,提交 PR 前请注意:
 
 - [社区论坛](https://forum.d2learn.org/category/20)
 - 交流群 QQ: 1067245099
-- [mcpp-index](https://github.com/mcpp-community/mcpp-index) — 默认包索引
+- [mcpp-index](https://github.com/mcpplibs/mcpp-index) — 默认包索引
 - [mcpplibs](https://github.com/mcpplibs) — 配套的模块化 C++ 库集合
diff --git a/mcpp.toml b/mcpp.toml
index 3435a0d1..ab063aad 100644
--- a/mcpp.toml
+++ b/mcpp.toml
@@ -1,6 +1,6 @@
 [package]
 name        = "mcpp"
-version     = "0.0.102"
+version     = "0.0.103"
 description = "Modern C++ build & package management tool"
 license     = "Apache-2.0"
 authors     = ["mcpp-community"]
diff --git a/src/config.cppm b/src/config.cppm
index dda011ce..9236972d 100644
--- a/src/config.cppm
+++ b/src/config.cppm
@@ -36,8 +36,22 @@ inline constexpr std::string_view kXlingsPinnedVersion = mcpp::xlings::pinned::k
 struct IndexRepo {
     std::string name;
     std::string url;
+    std::string artifact;   // optional artifact source base (xlings >= 0.4.68, #269)
+    std::string source;     // optional "auto" | "artifact" | "git" ("" = xlings default auto)
 };
 
+// Canonical mcpplibs index coordinates. The index repository moved from the
+// mcpp-community org to the mcpplibs org (#267) — the legacy URL only works
+// through GitHub's repo redirect, which breaks silently if the old name is
+// ever re-taken. The artifact base is the release mirror consumed by
+// xlings >= 0.4.68 per-repo artifact sync (#269); older xlings ignores it.
+inline constexpr std::string_view kMcpplibsIndexUrl =
+    "https://github.com/mcpplibs/mcpp-index.git";
+inline constexpr std::string_view kMcpplibsIndexUrlLegacy =
+    "https://github.com/mcpp-community/mcpp-index.git";
+inline constexpr std::string_view kMcpplibsIndexArtifact =
+    "https://github.com/xlings-res/mcpp-index";
+
 struct GlobalConfig {
     // Resolved paths
     std::filesystem::path           mcppHome;            // ~/.mcpp/
@@ -251,6 +265,12 @@ std::expected<GlobalConfig, ConfigError> load_or_init(
 // Pretty-print resolved config for `mcpp env` command.
 void print_env(const GlobalConfig& cfg);
 
+// Normalize legacy index naming in a loaded config (exported for tests):
+// org migration mcpp-community/mcpp-index -> mcpplibs/mcpp-index, index name
+// mcpp-index -> mcpplibs, then name+url dedup. Order matters: URL first, so
+// old-config name entries still match and legacy/default entries fold.
+void canonicalize_legacy_index_names(GlobalConfig& cfg);
+
 // M5.5: persist [toolchain].default to config.toml.
 std::expected<void, ConfigError>
 write_default_toolchain(const GlobalConfig& cfg, std::string_view spec);
@@ -357,7 +377,9 @@ home   = ""
 default = "mcpplibs"
 
 [index.repos."mcpplibs"]
-url = "https://github.com/mcpp-community/mcpp-index.git"
+url      = "https://github.com/mcpplibs/mcpp-index.git"
+artifact = "https://github.com/xlings-res/mcpp-index"
+# source = "auto"  # default: artifact first, git fallback; set "git" to force git
 # xlings auto-adds xim / awesome / scode / d2x as defaults.
 
 [cache]
@@ -375,10 +397,11 @@ bool write_default_xlings_json(const std::filesystem::path& path,
                                const std::vector<IndexRepo>& repos,
                                std::string_view mirror_override = {})
 {
-    // Delegate to xlings module. Convert IndexRepo vec to pair span.
-    std::vector<std::pair<std::string,std::string>> pairs;
+    // Delegate to xlings module. Convert IndexRepo vec to SeedRepo span.
+    std::vector<mcpp::xlings::SeedRepo> pairs;
     pairs.reserve(repos.size());
-    for (auto& r : repos) pairs.emplace_back(r.name, r.url);
+    for (auto& r : repos)
+        pairs.push_back({ r.name, r.url, r.artifact, r.source });
     // seed_xlings_json writes to env.home / ".xlings.json", so we
     // construct a temporary Env with home = path.parent_path().
     mcpp::xlings::Env env;
@@ -396,25 +419,8 @@ bool write_default_xlings_json(const std::filesystem::path& path,
 }
 
 // Migration helpers delegated to mcpp.fallback.config_migration.
-
-void canonicalize_legacy_index_names(GlobalConfig& cfg) {
-    if (cfg.defaultIndex == "mcpp-index")
-        cfg.defaultIndex = "mcpplibs";
-
-    std::vector<IndexRepo> normalized;
-    for (auto r : cfg.indexRepos) {
-        if (r.name == "mcpp-index"
-            && r.url == "https://github.com/mcpp-community/mcpp-index.git") {
-            r.name = "mcpplibs";
-        }
-        bool duplicate = std::any_of(normalized.begin(), normalized.end(),
-            [&](const IndexRepo& existing) {
-                return existing.name == r.name && existing.url == r.url;
-            });
-        if (!duplicate) normalized.push_back(std::move(r));
-    }
-    cfg.indexRepos = std::move(normalized);
-}
+// canonicalize_legacy_index_names is exported (declared above, defined after
+// this helper namespace) so its ordering rules stay under unit test.
 
 // Xlings binary acquisition delegated to mcpp.fallback.xlings_binary.
 
@@ -454,6 +460,35 @@ void ensure_sandbox_patchelf(const GlobalConfig& cfg, bool quiet,
 
 } // namespace
 
+void canonicalize_legacy_index_names(GlobalConfig& cfg) {
+    if (cfg.defaultIndex == "mcpp-index")
+        cfg.defaultIndex = "mcpplibs";
+
+    std::vector<IndexRepo> normalized;
+    for (auto r : cfg.indexRepos) {
+        // ① Org migration first — later steps (name match, dedup) key on the
+        // canonical URL, so legacy entries fold instead of surviving as dupes.
+        if (r.url == kMcpplibsIndexUrlLegacy)
+            r.url = std::string(kMcpplibsIndexUrl);
+        // ② Legacy index name. The URL condition keeps a user's unrelated
+        // repo that happens to be named "mcpp-index" untouched.
+        if (r.name == "mcpp-index" && r.url == kMcpplibsIndexUrl)
+            r.name = "mcpplibs";
+        // ③ In-memory artifact default for the official index (#269): heals
+        // configs written by pre-artifact templates on every load without
+        // text surgery on user-editable config.toml. `source = "git"` is the
+        // explicit opt-out; a user-set artifact base always wins.
+        if (r.url == kMcpplibsIndexUrl && r.artifact.empty() && r.source != "git")
+            r.artifact = std::string(kMcpplibsIndexArtifact);
+        bool duplicate = std::any_of(normalized.begin(), normalized.end(),
+            [&](const IndexRepo& existing) {
+                return existing.name == r.name && existing.url == r.url;
+            });
+        if (!duplicate) normalized.push_back(std::move(r));
+    }
+    cfg.indexRepos = std::move(normalized);
+}
+
 std::expected<GlobalConfig, ConfigError> load_or_init(
     bool quiet,
     BootstrapProgressCallback onBootstrapProgress,
@@ -538,7 +573,12 @@ std::expected<GlobalConfig, ConfigError> load_or_init(
             auto& tt = val.as_table();
             auto it = tt.find("url");
             if (it == tt.end() || !it->second.is_string()) continue;
-            cfg.indexRepos.push_back({ name, it->second.as_string() });
+            IndexRepo r{ name, it->second.as_string() };
+            if (auto a = tt.find("artifact"); a != tt.end() && a->second.is_string())
+                r.artifact = a->second.as_string();
+            if (auto s = tt.find("source"); s != tt.end() && s->second.is_string())
+                r.source = s->second.as_string();
+            cfg.indexRepos.push_back(std::move(r));
         }
     }
     // [indices] — new-schema custom index repositories.
@@ -556,6 +596,8 @@ std::expected<GlobalConfig, ConfigError> load_or_init(
                 if (auto it = sub.find("tag");    it != sub.end() && it->second.is_string()) spec.tag    = it->second.as_string();
                 if (auto it = sub.find("branch"); it != sub.end() && it->second.is_string()) spec.branch = it->second.as_string();
                 if (auto it = sub.find("path");   it != sub.end() && it->second.is_string()) spec.path   = it->second.as_string();
+                if (auto it = sub.find("artifact"); it != sub.end() && it->second.is_string()) spec.artifact = it->second.as_string();
+                if (auto it = sub.find("source");   it != sub.end() && it->second.is_string()) spec.source   = it->second.as_string();
             }
             if (!spec.url.empty() || !spec.path.empty())
                 cfg.indices[k] = std::move(spec);
@@ -568,11 +610,13 @@ std::expected<GlobalConfig, ConfigError> load_or_init(
     // them ourselves can cause cross-index name conflicts during
     // dependency resolution (e.g. linux-headers existing in both
     // scode and xim). See docs/21 §VII.
-    auto add_default = [&](std::string_view name, std::string_view url) {
+    auto add_default = [&](std::string_view name, std::string_view url,
+                           std::string_view artifact = {}) {
         for (auto& r : cfg.indexRepos) if (r.name == name) return;
-        cfg.indexRepos.push_back({ std::string(name), std::string(url) });
+        cfg.indexRepos.push_back({ std::string(name), std::string(url),
+                                   std::string(artifact), std::string() });
     };
-    add_default("mcpplibs", "https://github.com/mcpp-community/mcpp-index.git");
+    add_default("mcpplibs", kMcpplibsIndexUrl, kMcpplibsIndexArtifact);
     canonicalize_legacy_index_names(cfg);
 
     // 5. Seed registry/.xlings.json if missing; migrate legacy cached
@@ -651,6 +695,7 @@ std::expected<GlobalConfig, ConfigError> load_or_init(
 void print_env(const GlobalConfig& cfg) {
     std::println("MCPP_HOME           = {}", cfg.mcppHome.string());
     std::println("xlings binary       = {}", cfg.xlingsBinary.string());
+    std::println("xlings pinned       = {}", kXlingsPinnedVersion);
     std::println("xlings home         = {}", cfg.xlingsHome().string());
     std::println("config              = {}", cfg.configFile.string());
     std::println("BMI cache           = {}", cfg.bmiCacheDir.string());
@@ -663,8 +708,10 @@ void print_env(const GlobalConfig& cfg) {
     std::println("Index repos:");
     for (auto& r : cfg.indexRepos) {
         bool isDefault = (r.name == cfg.defaultIndex);
-        std::println("  {} {}{}",
-                     r.name, r.url, isDefault ? "  (default)" : "");
+        std::println("  {} {}{}{}",
+                     r.name, r.url,
+                     r.artifact.empty() ? "" : "  [artifact]",
+                     isDefault ? "  (default)" : "");
     }
 }
 
@@ -677,17 +724,28 @@ bool ensure_project_index_dir(
     // Collect custom non-builtin indices that need xlings project-scope data.
     // Local path indices are also seeded so xlings can create its own
     // project-local repo link and install packages from that index.
-    std::vector<std::pair<std::string,std::string>> customRepos;
+    std::vector<mcpp::xlings::SeedRepo> customRepos;
     for (auto& [name, spec] : indices) {
         if (spec.is_builtin()) continue;
         if (spec.is_local()) {
             auto source = resolve_project_index_path(projectDir, spec);
             std::error_code ec;
             std::filesystem::remove(source / ".xlings-index-cache.json", ec);
-            customRepos.emplace_back(name, source.generic_string());
+            customRepos.push_back({ name, source.generic_string(), "", "" });
             continue;
         }
-        customRepos.emplace_back(name, spec.url);
+        // #269: pass a declared artifact source through to xlings unless a
+        // rev/tag/branch pin forces git (the artifact channel only tracks
+        // the latest published pointer).
+        mcpp::xlings::SeedRepo repo{ name, spec.url, "", "" };
+        if (spec.artifact_applicable()) {
+            repo.artifact = spec.artifact;
+            repo.source   = spec.source;
+        } else if (!spec.artifact.empty()) {
+            std::println("warning: [indices].{}: artifact source ignored "
+                         "(rev/tag/branch/path pins force git)", name);
+        }
+        customRepos.push_back(std::move(repo));
     }
 
     // NOTE: the official global `xim` index is deliberately NOT injected into
diff --git a/src/fallback/config_migration.cppm b/src/fallback/config_migration.cppm
index 555119e0..56e75872 100644
--- a/src/fallback/config_migration.cppm
+++ b/src/fallback/config_migration.cppm
@@ -1,8 +1,12 @@
-// mcpp.fallback.config_migration — legacy index name migration.
+// mcpp.fallback.config_migration — legacy index config migration.
 //
-// Older mcpp sandboxes used "mcpp-index" as the default index name.
-// These helpers rename it to "mcpplibs" in config.toml and .xlings.json
-// so xlings config/list output matches mcpp's default namespace.
+// Older mcpp sandboxes used "mcpp-index" as the default index name and the
+// pre-migration mcpp-community org URL. These helpers rename the index to
+// "mcpplibs", rewrite the org URL (#267), and inject the xlings >= 0.4.68
+// per-repo artifact declaration (#269) into config.toml / .xlings.json.
+// Deliberately text-based: .xlings.json carries xlings-owned state (subos,
+// version bindings) that a regeneration would destroy. This is a LEAF
+// module (no mcpp.config import), so the URL literals are repeated here.
 
 export module mcpp.fallback.config_migration;
 
@@ -62,6 +66,9 @@ bool migrate_config_toml_index_names(const std::filesystem::path& path) {
 
     replace_all(updated, "default = \"mcpp-index\"", "default = \"mcpplibs\"");
     replace_all(updated, "[index.repos.\"mcpp-index\"]", "[index.repos.\"mcpplibs\"]");
+    // Org migration (#267): the index repo moved to the mcpplibs org.
+    replace_all(updated, "https://github.com/mcpp-community/mcpp-index.git",
+                         "https://github.com/mcpplibs/mcpp-index.git");
 
     return write_text_if_changed(path, original, updated);
 }
@@ -76,6 +83,25 @@ bool migrate_xlings_json_index_names(const std::filesystem::path& path) {
 
     replace_all(updated, "\"name\": \"mcpp-index\"", "\"name\": \"mcpplibs\"");
     replace_all(updated, "\"name\":\"mcpp-index\"", "\"name\":\"mcpplibs\"");
+    // Org migration (#267): the index repo moved to the mcpplibs org.
+    replace_all(updated, "https://github.com/mcpp-community/mcpp-index.git",
+                         "https://github.com/mcpplibs/mcpp-index.git");
+
+    // Artifact injection (#269, xlings >= 0.4.68 per-repo artifact source).
+    // Existing installs never re-seed .xlings.json, so this migration is
+    // their only channel to the artifact declaration; older xlings safely
+    // ignores the key. Idempotency gate: the res base appearing anywhere
+    // means a previous run (or a fresh seed) already declared it — a plain
+    // replace_all would re-inject on every run. Both spacing variants
+    // because the file has two writers (mcpp pretty / xlings compact).
+    if (updated.find("xlings-res/mcpp-index") == std::string::npos) {
+        constexpr std::string_view art =
+            ", \"artifact\": \"https://github.com/xlings-res/mcpp-index\"";
+        for (std::string_view urlkv : {
+                "\"url\": \"https://github.com/mcpplibs/mcpp-index.git\"",
+                "\"url\":\"https://github.com/mcpplibs/mcpp-index.git\"" })
+            replace_all(updated, urlkv, std::string(urlkv) + std::string(art));
+    }
 
     return write_text_if_changed(path, original, updated);
 }
diff --git a/src/manifest/toml.cppm b/src/manifest/toml.cppm
index 5bed64c1..77c5a661 100644
--- a/src/manifest/toml.cppm
+++ b/src/manifest/toml.cppm
@@ -1146,6 +1146,8 @@ std::expected<Manifest, ManifestError> parse_string(std::string_view content,
                 if (auto it = sub.find("tag");    it != sub.end() && it->second.is_string()) spec.tag    = it->second.as_string();
                 if (auto it = sub.find("branch"); it != sub.end() && it->second.is_string()) spec.branch = it->second.as_string();
                 if (auto it = sub.find("path");   it != sub.end() && it->second.is_string()) spec.path   = it->second.as_string();
+                if (auto it = sub.find("artifact"); it != sub.end() && it->second.is_string()) spec.artifact = it->second.as_string();
+                if (auto it = sub.find("source");   it != sub.end() && it->second.is_string()) spec.source   = it->second.as_string();
                 if (spec.url.empty() && spec.path.empty()) {
                     return std::unexpected(error(origin, std::format(
                         "[indices].{} must specify 'url' or 'path'", k)));
diff --git a/src/pm/index_spec.cppm b/src/pm/index_spec.cppm
index 27110100..4ee2245b 100644
--- a/src/pm/index_spec.cppm
+++ b/src/pm/index_spec.cppm
@@ -18,9 +18,18 @@ struct IndexSpec {
     std::string              tag;       // git tag
     std::string              branch;    // git branch
     std::filesystem::path    path;      // local path (takes priority over url)
+    std::string              artifact;  // optional artifact source base (xlings >= 0.4.68, #269)
+    std::string              source;    // optional "auto" | "artifact" | "git"
 
     bool is_local()   const { return !path.empty(); }
     bool is_pinned()  const { return !rev.empty(); }
+    // The artifact channel only tracks the latest published pointer; any
+    // rev/tag/branch pin (and local path) therefore forces git and the
+    // artifact declaration is ignored (with a warning at seed time).
+    bool artifact_applicable() const {
+        return !artifact.empty() && rev.empty() && tag.empty()
+            && branch.empty() && path.empty();
+    }
     // R6: `name == "mcpplibs"` alone used to mean "builtin" unconditionally,
     // which was correct while the only way to reach that name was the
     // literal `[indices] mcpplibs = { url = ..., rev = ... }` pin form (still
diff --git a/src/publish/pipeline.cppm b/src/publish/pipeline.cppm
index b69ea491..aa639a6a 100644
--- a/src/publish/pipeline.cppm
+++ b/src/publish/pipeline.cppm
@@ -155,7 +155,7 @@ export int publish_package(bool dry_run, bool allow_dirty) {
     std::println("       Attach: {}", tarball.string());
     std::println("");
     std::println("  3. Open a PR to mcpp-index:");
-    std::println("       Fork:  https://github.com/mcpp-community/mcpp-index");
+    std::println("       Fork:  https://github.com/mcpplibs/mcpp-index");
     std::println("       Add:   pkgs/{}/{}.lua", first, pkg.name);
     std::println("       (file content is in {})", xpkgPath.string());
     std::println("");
diff --git a/src/toolchain/fingerprint.cppm b/src/toolchain/fingerprint.cppm
index ba3ef157..826fac1b 100644
--- a/src/toolchain/fingerprint.cppm
+++ b/src/toolchain/fingerprint.cppm
@@ -18,7 +18,7 @@ import mcpp.toolchain.detect;
 
 export namespace mcpp::toolchain {
 
-inline constexpr std::string_view MCPP_VERSION = "0.0.102";
+inline constexpr std::string_view MCPP_VERSION = "0.0.103";
 
 struct FingerprintInputs {
     Toolchain                       toolchain;
diff --git a/src/xlings.cppm b/src/xlings.cppm
index 7c4ee5eb..e06fe7be 100644
--- a/src/xlings.cppm
+++ b/src/xlings.cppm
@@ -33,7 +33,10 @@ struct Env {
 namespace pinned {
     inline constexpr std::string_view kPatchelfVersion = "0.18.0";
     inline constexpr std::string_view kNinjaVersion    = "1.12.1";
-    inline constexpr std::string_view kXlingsVersion   = "0.4.51";
+    // Keep in lock-step with the XLINGS_VERSION pins in release.yml /
+    // cross-build-test.yml / ci-linux-e2e.yml (the xlings actually bundled
+    // into releases). Printed by `mcpp self env`.
+    inline constexpr std::string_view kXlingsVersion   = "0.4.68";
     inline constexpr std::string_view kNasmVersion     = "3.02";
 }
 
@@ -247,8 +250,19 @@ struct ProjectEnv {
     }
 };
 
+// One index_repos entry for seed_xlings_json. `artifact`/`source` are the
+// xlings >= 0.4.68 per-repo artifact-sync fields (#269); empty means "do not
+// emit the key", which keeps pre-artifact output byte-identical and matches
+// xlings' "undeclared = plain git" semantics. Older xlings ignores both keys.
+struct SeedRepo {
+    std::string name;
+    std::string url;
+    std::string artifact;   // artifact source base, e.g. https://github.com/xlings-res/mcpp-index
+    std::string source;     // "auto" | "artifact" | "git"
+};
+
 void seed_xlings_json(const Env& env,
-                      std::span<const std::pair<std::string,std::string>> repos,
+                      std::span<const SeedRepo> repos,
                       std::string_view mirror = "auto",
                       const ProjectEnv& penv = {});
 
@@ -1108,7 +1122,7 @@ int install_direct(const Env& env, std::string_view target, bool quiet) {
 // ─── Sandbox lifecycle ──────────────────────────────────────────────
 
 void seed_xlings_json(const Env& env,
-                      std::span<const std::pair<std::string,std::string>> repos,
+                      std::span<const SeedRepo> repos,
                       std::string_view mirror,
                       const ProjectEnv& penv)
 {
@@ -1116,10 +1130,16 @@ void seed_xlings_json(const Env& env,
     std::string json = "{\n";
     json += "  \"index_repos\": [\n";
     for (std::size_t i = 0; i < repos.size(); ++i) {
-        json += std::format("    {{ \"name\": \"{}\", \"url\": \"{}\" }}{}\n",
-                            json_escape(repos[i].first),
-                            json_escape(repos[i].second),
-                            i + 1 == repos.size() ? "" : ",");
+        json += std::format("    {{ \"name\": \"{}\", \"url\": \"{}\"",
+                            json_escape(repos[i].name),
+                            json_escape(repos[i].url));
+        if (!repos[i].artifact.empty())
+            json += std::format(", \"artifact\": \"{}\"",
+                                json_escape(repos[i].artifact));
+        if (!repos[i].source.empty())
+            json += std::format(", \"source\": \"{}\"",
+                                json_escape(repos[i].source));
+        json += std::format(" }}{}\n", i + 1 == repos.size() ? "" : ",");
     }
     json += "  ],\n";
     // [xlings] build environment (L-1): materialize deps/workspace/subos/envs
diff --git a/tests/e2e/151_index_url_artifact_migration.sh b/tests/e2e/151_index_url_artifact_migration.sh
new file mode 100755
index 00000000..1ad8c745
--- /dev/null
+++ b/tests/e2e/151_index_url_artifact_migration.sh
@@ -0,0 +1,79 @@
+#!/usr/bin/env bash
+# #267/#269: fresh init seeds the mcpplibs-org index URL + artifact source;
+# legacy config.toml / .xlings.json (old org URL, no artifact) are healed in
+# place, idempotently, in both pretty (mcpp writer) and compact (xlings
+# writer) JSON spacings. Unrelated .xlings.json state must survive.
+set -e
+
+TMP=$(mktemp -d)
+trap "rm -rf $TMP" EXIT
+
+export MCPP_HOME="$TMP/mcpp-home"
+
+NEW_URL='https://github.com/mcpplibs/mcpp-index.git'
+OLD_URL='https://github.com/mcpp-community/mcpp-index.git'
+ART='https://github.com/xlings-res/mcpp-index'
+CFG="$MCPP_HOME/config.toml"
+XJ="$MCPP_HOME/registry/.xlings.json"
+
+# 1. Fresh init: new org URL + artifact declaration in both files.
+# (xlings' own bootstrap may re-serialize .xlings.json with its writer, so
+# assert on the key/value pairs, not on mcpp's seed line layout.)
+"$MCPP" self env > /dev/null
+grep -q "url      = \"$NEW_URL\"" "$CFG"  || { echo "config.toml missing new url"; exit 1; }
+grep -q "artifact = \"$ART\"" "$CFG"      || { echo "config.toml missing artifact"; exit 1; }
+grep -q "\"url\": \"$NEW_URL\"" "$XJ" \
+    || { echo "seeded .xlings.json missing new url"; cat "$XJ"; exit 1; }
+grep -q "\"artifact\": \"$ART\"" "$XJ" \
+    || { echo "seeded .xlings.json missing artifact"; cat "$XJ"; exit 1; }
+if grep -q 'mcpp-community/mcpp-index' "$CFG" "$XJ"; then
+    echo "old org URL leaked into fresh seed"; exit 1
+fi
+
+# 2. Legacy heal (pretty spacing): old org URL, no artifact.
+cat > "$CFG" <<EOF
+[xlings]
+binary = "bundled"
+home   = ""
+
+[index]
+default = "mcpplibs"
+
+[index.repos."mcpplibs"]
+url = "$OLD_URL"
+EOF
+cat > "$XJ" <<EOF
+{
+  "index_repos": [
+    { "name": "mcpplibs", "url": "$OLD_URL" }
+  ],
+  "subos": "default",
+  "lang": "en",
+  "mirror": "auto"
+}
+EOF
+"$MCPP" self env > /dev/null
+grep -q "url = \"$NEW_URL\"" "$CFG"       || { echo "config.toml url not healed"; cat "$CFG"; exit 1; }
+grep -q "\"url\": \"$NEW_URL\", \"artifact\": \"$ART\"" "$XJ" \
+    || { echo ".xlings.json not healed"; cat "$XJ"; exit 1; }
+grep -q '"subos": "default"' "$XJ"        || { echo "unrelated .xlings.json key lost"; exit 1; }
+if grep -q 'mcpp-community/mcpp-index' "$CFG" "$XJ"; then
+    echo "old org URL survived heal"; exit 1
+fi
+
+# Idempotent: a second run must not touch either file again.
+cp "$CFG" "$TMP/cfg1"; cp "$XJ" "$TMP/xj1"
+"$MCPP" self env > /dev/null
+cmp -s "$CFG" "$TMP/cfg1" || { echo "config.toml heal not idempotent"; exit 1; }
+cmp -s "$XJ" "$TMP/xj1"   || { echo ".xlings.json heal not idempotent"; exit 1; }
+
+# 3. Legacy heal (compact spacing, old index name): xlings-writer format.
+printf '{"index_repos":[{"name":"mcpp-index","url":"%s"}],"mirror":"auto"}' "$OLD_URL" > "$XJ"
+"$MCPP" self env > /dev/null
+grep -q '"name":"mcpplibs"' "$XJ"      || { echo "compact name not healed"; cat "$XJ"; exit 1; }
+grep -q 'xlings-res/mcpp-index' "$XJ"  || { echo "compact artifact not injected"; cat "$XJ"; exit 1; }
+if grep -q 'mcpp-community' "$XJ"; then
+    echo "compact old org URL survived"; exit 1
+fi
+
+echo "OK"
diff --git a/tests/unit/test_config.cpp b/tests/unit/test_config.cpp
index 6e07cc26..f3d1f2d1 100644
--- a/tests/unit/test_config.cpp
+++ b/tests/unit/test_config.cpp
@@ -5,6 +5,7 @@
 
 import std;
 import mcpp.config;
+import mcpp.fallback.config_migration;
 import mcpp.pm.index_spec;
 
 namespace {
@@ -162,3 +163,151 @@ TEST(Config, ProjectLocalIndexStaleCacheIsRemoved) {
 
     std::filesystem::remove_all(project);
 }
+
+// ── #267-A/#269: index org migration + artifact adoption ────────────────────
+
+namespace {
+
+std::string read_all(const std::filesystem::path& p) {
+    std::stringstream ss;
+    ss << std::ifstream(p).rdbuf();
+    return ss.str();
+}
+
+}  // namespace
+
+TEST(ConfigIndexMigration, CanonicalizeRewritesOrgAndName) {
+    mcpp::config::GlobalConfig cfg;
+    cfg.defaultIndex = "mcpp-index";
+    cfg.indexRepos.push_back({ "mcpp-index",
+        std::string(mcpp::config::kMcpplibsIndexUrlLegacy) });
+    mcpp::config::canonicalize_legacy_index_names(cfg);
+    ASSERT_EQ(cfg.indexRepos.size(), 1u);
+    EXPECT_EQ(cfg.defaultIndex, "mcpplibs");
+    EXPECT_EQ(cfg.indexRepos[0].name, "mcpplibs");
+    EXPECT_EQ(cfg.indexRepos[0].url,  mcpp::config::kMcpplibsIndexUrl);
+}
+
+TEST(ConfigIndexMigration, CanonicalizeFoldsLegacyAndDefaultEntries) {
+    mcpp::config::GlobalConfig cfg;
+    cfg.indexRepos.push_back({ "mcpplibs",
+        std::string(mcpp::config::kMcpplibsIndexUrlLegacy) });
+    cfg.indexRepos.push_back({ "mcpplibs",
+        std::string(mcpp::config::kMcpplibsIndexUrl) });
+    mcpp::config::canonicalize_legacy_index_names(cfg);
+    EXPECT_EQ(cfg.indexRepos.size(), 1u);
+}
+
+TEST(ConfigIndexMigration, CanonicalizeLeavesForeignReposAlone) {
+    mcpp::config::GlobalConfig cfg;
+    cfg.indexRepos.push_back({ "other", "https://example.com/other-index.git" });
+    mcpp::config::canonicalize_legacy_index_names(cfg);
+    ASSERT_EQ(cfg.indexRepos.size(), 1u);
+    EXPECT_EQ(cfg.indexRepos[0].name, "other");
+    EXPECT_EQ(cfg.indexRepos[0].url, "https://example.com/other-index.git");
+}
+
+TEST(ConfigIndexMigration, MigrateConfigTomlRewritesOrgUrlIdempotently) {
+    auto dir = make_tempdir("mcpp-migrate-toml");
+    auto p = dir / "config.toml";
+    {
+        std::ofstream os(p);
+        os << "[index]\ndefault = \"mcpplibs\"\n\n[index.repos.\"mcpplibs\"]\n"
+              "url = \"https://github.com/mcpp-community/mcpp-index.git\"\n";
+    }
+    EXPECT_TRUE(mcpp::fallback::migrate_config_toml_index_names(p));
+    auto text = read_all(p);
+    EXPECT_NE(text.find("github.com/mcpplibs/mcpp-index.git"), std::string::npos);
+    EXPECT_EQ(text.find("mcpp-community/mcpp-index"), std::string::npos);
+    EXPECT_FALSE(mcpp::fallback::migrate_config_toml_index_names(p));  // idempotent
+    EXPECT_EQ(read_all(p), text);
+    std::filesystem::remove_all(dir);
+}
+
+TEST(ConfigIndexMigration, CanonicalizeFillsDefaultArtifactForOfficialRepo) {
+    mcpp::config::GlobalConfig cfg;
+    cfg.indexRepos.push_back({ "mcpplibs",
+        std::string(mcpp::config::kMcpplibsIndexUrlLegacy) });
+    mcpp::config::canonicalize_legacy_index_names(cfg);
+    ASSERT_EQ(cfg.indexRepos.size(), 1u);
+    EXPECT_EQ(cfg.indexRepos[0].artifact, mcpp::config::kMcpplibsIndexArtifact);
+}
+
+TEST(ConfigIndexMigration, CanonicalizeRespectsExplicitGitSourceAndCustomArtifact) {
+    mcpp::config::GlobalConfig cfg;
+    mcpp::config::IndexRepo git{ "mcpplibs",
+        std::string(mcpp::config::kMcpplibsIndexUrl) };
+    git.source = "git";
+    cfg.indexRepos.push_back(git);
+    mcpp::config::IndexRepo custom{ "mirror",
+        std::string(mcpp::config::kMcpplibsIndexUrl) };
+    custom.artifact = "https://example.com/my-mirror";
+    cfg.indexRepos.push_back(custom);
+    cfg.indexRepos.push_back({ "other", "https://example.com/other-index.git" });
+    mcpp::config::canonicalize_legacy_index_names(cfg);
+    ASSERT_EQ(cfg.indexRepos.size(), 3u);
+    EXPECT_TRUE(cfg.indexRepos[0].artifact.empty());        // explicit git opt-out
+    EXPECT_EQ(cfg.indexRepos[1].artifact, "https://example.com/my-mirror");
+    EXPECT_TRUE(cfg.indexRepos[2].artifact.empty());        // foreign repo untouched
+}
+
+TEST(ConfigIndexMigration, XlingsJsonHealsPrettyLegacyEntry) {
+    auto dir = make_tempdir("mcpp-migrate-xj");
+    auto p = dir / ".xlings.json";
+    {
+        std::ofstream os(p);
+        os << "{\n  \"index_repos\": [\n"
+              "    { \"name\": \"mcpplibs\", \"url\": "
+              "\"https://github.com/mcpp-community/mcpp-index.git\" }\n"
+              "  ],\n  \"subos\": \"default\",\n  \"mirror\": \"auto\"\n}\n";
+    }
+    EXPECT_TRUE(mcpp::fallback::migrate_xlings_json_index_names(p));
+    auto text = read_all(p);
+    EXPECT_NE(text.find(
+        "\"url\": \"https://github.com/mcpplibs/mcpp-index.git\", "
+        "\"artifact\": \"https://github.com/xlings-res/mcpp-index\""),
+        std::string::npos) << text;
+    EXPECT_NE(text.find("\"subos\": \"default\""), std::string::npos);
+    EXPECT_EQ(text.find("mcpp-community/mcpp-index"), std::string::npos);
+    EXPECT_FALSE(mcpp::fallback::migrate_xlings_json_index_names(p));  // idempotent
+    EXPECT_EQ(read_all(p), text);
+    std::filesystem::remove_all(dir);
+}
+
+TEST(ConfigIndexMigration, XlingsJsonHealsCompactLegacyNameAndUrl) {
+    auto dir = make_tempdir("mcpp-migrate-xjc");
+    auto p = dir / ".xlings.json";
+    {
+        std::ofstream os(p);
+        os << "{\"index_repos\":[{\"name\":\"mcpp-index\","
+              "\"url\":\"https://github.com/mcpp-community/mcpp-index.git\"}],"
+              "\"mirror\":\"auto\"}";
+    }
+    EXPECT_TRUE(mcpp::fallback::migrate_xlings_json_index_names(p));
+    auto text = read_all(p);
+    EXPECT_NE(text.find("\"name\":\"mcpplibs\""), std::string::npos);
+    EXPECT_NE(text.find(
+        "\"url\":\"https://github.com/mcpplibs/mcpp-index.git\", "
+        "\"artifact\": \"https://github.com/xlings-res/mcpp-index\""),
+        std::string::npos) << text;
+    EXPECT_FALSE(mcpp::fallback::migrate_xlings_json_index_names(p));
+    std::filesystem::remove_all(dir);
+}
+
+TEST(ConfigIndexMigration, XlingsJsonSkipsInjectionWhenArtifactPresent) {
+    auto dir = make_tempdir("mcpp-migrate-xja");
+    auto p = dir / ".xlings.json";
+    std::string body =
+        "{\n  \"index_repos\": [\n"
+        "    { \"name\": \"mcpplibs\", \"url\": "
+        "\"https://github.com/mcpplibs/mcpp-index.git\", "
+        "\"artifact\": \"https://github.com/xlings-res/mcpp-index\" }\n"
+        "  ]\n}\n";
+    {
+        std::ofstream os(p);
+        os << body;
+    }
+    EXPECT_FALSE(mcpp::fallback::migrate_xlings_json_index_names(p));
+    EXPECT_EQ(read_all(p), body);
+    std::filesystem::remove_all(dir);
+}
diff --git a/tests/unit/test_manifest.cpp b/tests/unit/test_manifest.cpp
index ee855509..ed9b65fb 100644
--- a/tests/unit/test_manifest.cpp
+++ b/tests/unit/test_manifest.cpp
@@ -2601,3 +2601,30 @@ mcpp = {
     EXPECT_EQ(host->modules.sources, nativeTarget->modules.sources);
     EXPECT_EQ(host->buildConfig.cxxflags, nativeTarget->buildConfig.cxxflags);
 }
+
+TEST(Manifest, IndicesArtifactAndSourceParsedAndPinSuppresses) {
+    // #269: [indices] entries may declare an xlings >= 0.4.68 artifact
+    // source. rev/tag/branch pins force git (the artifact channel only
+    // tracks the latest pointer), which artifact_applicable() encodes.
+    constexpr auto src = R"(
+[package]
+name = "hello"
+version = "0.1.0"
+[language]
+standard = "c++23"
+[modules]
+sources = ["src/**/*.cppm"]
+[indices]
+fast   = { url = "https://example.com/i.git", artifact = "https://example.com/res/i", source = "auto" }
+pinned = { url = "https://example.com/i.git", artifact = "https://example.com/res/i", rev = "abc123" }
+)";
+    auto m = mcpp::manifest::parse_string(src);
+    ASSERT_TRUE(m.has_value()) << m.error().format();
+    auto& fast = m->indices.at("fast");
+    EXPECT_EQ(fast.artifact, "https://example.com/res/i");
+    EXPECT_EQ(fast.source, "auto");
+    EXPECT_TRUE(fast.artifact_applicable());
+    auto& pinned = m->indices.at("pinned");
+    EXPECT_EQ(pinned.artifact, "https://example.com/res/i");
+    EXPECT_FALSE(pinned.artifact_applicable());
+}
diff --git a/tests/unit/test_pm_package_fetcher.cpp b/tests/unit/test_pm_package_fetcher.cpp
index 856eadbc..d5421057 100644
--- a/tests/unit/test_pm_package_fetcher.cpp
+++ b/tests/unit/test_pm_package_fetcher.cpp
@@ -253,3 +253,25 @@ TEST(PmPackageFetcher, ReadSeededIndexReposParsesXlingsJson) {
 
     std::filesystem::remove_all(project);
 }
+
+TEST(PmPackageFetcher, ReadSeededIndexReposToleratesArtifactFields) {
+    // #269: entries seeded with per-repo artifact/source keys (xlings >=
+    // 0.4.68) must still yield name+url — regression lock for the hand-
+    // rolled index_repos reader.
+    auto project = make_tempdir("mcpp-269-artifact-fields");
+    auto xjson = project / ".xlings.json";
+    write_file(xjson, R"({
+  "index_repos": [
+    { "name": "mcpplibs", "url": "https://github.com/mcpplibs/mcpp-index.git", "artifact": "https://github.com/xlings-res/mcpp-index", "source": "auto" }
+  ],
+  "lang": "en"
+})");
+
+    auto repos = mcpp::pm::read_seeded_index_repos(xjson);
+    ASSERT_EQ(repos.size(), 1u);
+    EXPECT_NE(repos[0].find("mcpplibs"), std::string::npos);
+    EXPECT_NE(repos[0].find("https://github.com/mcpplibs/mcpp-index.git"),
+              std::string::npos);
+
+    std::filesystem::remove_all(project);
+}
diff --git a/tests/unit/test_xlings.cpp b/tests/unit/test_xlings.cpp
index ccbab5f3..01a54a1b 100644
--- a/tests/unit/test_xlings.cpp
+++ b/tests/unit/test_xlings.cpp
@@ -408,3 +408,49 @@ TEST(XlingsHomeTool, FindsPayloadUnderNonXimPrefix) {
 
     std::filesystem::remove_all(tmp);
 }
+
+// ─── seed_xlings_json — per-repo artifact/source emission (#269) ──────
+
+namespace {
+
+std::string read_seeded(const std::filesystem::path& home) {
+    std::stringstream ss;
+    ss << std::ifstream(home / ".xlings.json").rdbuf();
+    return ss.str();
+}
+
+}  // namespace
+
+TEST(XlingsSeed, PlainRepoEmissionIsByteStable) {
+    // Zero-diff gate: repos without artifact/source must serialize exactly
+    // as before the SeedRepo extension.
+    auto dir = make_tempdir("mcpp-seed-plain");
+    mcpp::xlings::Env env;
+    env.home = dir;
+    std::vector<mcpp::xlings::SeedRepo> repos{
+        { "mcpplibs", "https://x.git", "", "" } };
+    mcpp::xlings::seed_xlings_json(env, repos);
+    auto text = read_seeded(dir);
+    EXPECT_NE(text.find(
+        "    { \"name\": \"mcpplibs\", \"url\": \"https://x.git\" }\n"),
+        std::string::npos) << text;
+    EXPECT_EQ(text.find("artifact"), std::string::npos);
+    EXPECT_EQ(text.find("source"), std::string::npos);
+    std::filesystem::remove_all(dir);
+}
+
+TEST(XlingsSeed, ArtifactAndSourceEmittedWhenSet) {
+    auto dir = make_tempdir("mcpp-seed-art");
+    mcpp::xlings::Env env;
+    env.home = dir;
+    std::vector<mcpp::xlings::SeedRepo> repos{
+        { "mcpplibs", "https://x.git",
+          "https://github.com/xlings-res/mcpp-index", "auto" } };
+    mcpp::xlings::seed_xlings_json(env, repos);
+    auto text = read_seeded(dir);
+    EXPECT_NE(text.find(
+        "\"url\": \"https://x.git\", \"artifact\": "
+        "\"https://github.com/xlings-res/mcpp-index\", \"source\": \"auto\""),
+        std::string::npos) << text;
+    std::filesystem::remove_all(dir);
+}