diff --git a/.agents/docs/2026-10-14-add-gsl-plan.md b/.agents/docs/2026-10-14-add-gsl-plan.md
new file mode 100644
index 00000000..458c7053
--- /dev/null
+++ b/.agents/docs/2026-10-14-add-gsl-plan.md
@@ -0,0 +1,46 @@
+# 新增 GSL 收录（compat，install() 构建）
+
+## 1. 来源与形态
+
+- 收录 GNU Scientific Library 2.8，官方站点列出的当前稳定版本。
+- 采用 GNU 源码归档 `gsl-2.8.tar.gz`，SHA-256 为
+  `6a99eeed15632c6354895b1dd542ed5a855c0f15d9ad1326c6fe2b2c9e423190`。
+- GSL 2.8 是 autotools 工程：`configure` 生成 `config.h`，顶层构建再通过 libtool
+  组合 `libgsl.a` 和 `libgslcblas.a`。其源码树包含大量相互依赖的子库和测试源，不能用
+  一个宽泛的 `sources` glob 安全表达生产库边界。
+- 描述符因此采用与 `compat.openblas`/`compat.openssl` 相同的 `install()` 触发方式：
+  构建期运行上游 `configure`、`make`、`make install`，然后由 hook 写入 anchor TU。
+
+## 2. 描述符设计
+
+- 身份为 `compat:gsl`，文件为 `pkgs/c/compat.gsl.lua`。
+- Linux 使用官方源码包和 `xim:make@latest`，macOS 使用系统自带的 GNU Make；
+  关闭 shared、启用 static，产物安装到包的 `include/` 与 `lib/`。
+- hook 显式使用 `CFLAGS=-std=c11`。GSL 2.8 的 configure 探测包含旧式 C
+  兼容性代码，在 GCC 16 的默认 C23 模式下会被拒绝；固定到 C11 同时符合
+  GSL 的 ANSI C 构建要求，并保持 Linux CI 与本地工具链一致。
+- Linux hook 显式选择 `/usr/bin/gcc`，而不是 PATH 中可能由 xlings 注入的
+  payload compiler。GSL configure 会编译并运行 ABI 探测程序，宿主编译器
+  保证这些探测程序能在 CI runner 上执行。
+- 消费侧公开 `include/gsl/*.h`，链接顺序为 `libgsl`、`libgslcblas`、`libm`。
+- GSL 自带 CBLAS 随包默认提供，不再声明或隐式绑定 `compat.openblas`，避免 BLAS ABI
+  和符号来源不明确。
+- Windows 暂不声明 xpm 版本：官方 2.8 归档没有原生 MSVC 构建路径，当前 index 也不
+  应凭空引入未经验证的预编译库。测试工程在非 Unix 平台编译 no-op。
+
+## 3. Feature 评估
+
+GSL 的各数值领域在上游构建中共同链接到 `libgsl`，不是可以由 mcpp `features`
+（只能可靠门控源码列表）独立切分的消费者组件，因此本版本不增加 feature。CBLAS
+同样作为完整 GSL 的默认组成部分。
+
+## 4. 测试与验证目标
+
+`tests/examples/gsl` 覆盖：
+
+- Bessel 特殊函数；
+- 自适应积分；
+- CBLAS `ddot` 的链接和结果。
+
+验证包括描述符 lint、`mcpp xpkg parse`、`mcpp test -p gsl`，以及一次清理缓存后的
+冷构建，确认头文件和两个静态归档来自该包而不是宿主系统。
diff --git a/mcpp.toml b/mcpp.toml
index 179e43c5..83ad9f21 100644
--- a/mcpp.toml
+++ b/mcpp.toml
@@ -62,6 +62,7 @@ members = [
     "tests/examples/gzip-hpp",
     "tests/examples/huxerui-module",
     "tests/examples/gmp-gmpxx",
+    "tests/examples/gsl",
     "tests/examples/godot-cpp",
     "tests/examples/godot-cpp-module",
     "tests/examples/godot-cpp-module-v10",
diff --git a/pkgs/c/compat.gsl.lua b/pkgs/c/compat.gsl.lua
new file mode 100644
index 00000000..60939aa2
--- /dev/null
+++ b/pkgs/c/compat.gsl.lua
@@ -0,0 +1,156 @@
+-- compat.gsl -- GNU Scientific Library 2.8, built from the official
+-- autotools release. GSL's configure step generates config.h and libtool
+-- assembles two archives, so the install hook is used instead of trying to
+-- approximate the upstream source graph with broad globs.
+--
+-- The package exposes both libgsl and the GSL CBLAS implementation. Windows
+-- is intentionally not declared: the official release has no native MSVC
+-- build system, and silently using a host or third-party binary would break
+-- the index's source-build and ABI guarantees.
+package = {
+    spec        = "1",
+    namespace   = "compat",
+    name        = "gsl",
+    description = "GNU Scientific Library with its CBLAS implementation (static, source-built)",
+    licenses    = {"GPL-3.0-or-later"},
+    repo        = "https://www.gnu.org/software/gsl/",
+    type        = "package",
+
+    xpm = {
+        linux = {
+            deps = { "xim:make@latest" },
+            ["2.8"] = {
+                url = "https://ftp.gnu.org/gnu/gsl/gsl-2.8.tar.gz",
+                sha256 = "6a99eeed15632c6354895b1dd542ed5a855c0f15d9ad1326c6fe2b2c9e423190",
+            },
+        },
+        macosx = {
+            ["2.8"] = {
+                url = "https://ftp.gnu.org/gnu/gsl/gsl-2.8.tar.gz",
+                sha256 = "6a99eeed15632c6354895b1dd542ed5a855c0f15d9ad1326c6fe2b2c9e423190",
+            },
+        },
+    },
+
+    mcpp = {
+        language     = "c++23",
+        import_std   = false,
+        c_standard   = "c11",
+        sources      = { "mcpp_gsl_anchor.c" },
+        include_dirs = { "include" },
+        targets      = { ["gsl"] = { kind = "lib" } },
+        linux = {
+            ldflags = { "-Llib", "-lgsl", "-lgslcblas", "-lm" },
+        },
+        macosx = {
+            ldflags = { "-Llib", "-lgsl", "-lgslcblas", "-lm" },
+        },
+    },
+}
+
+import("xim.libxpkg.pkginfo")
+import("xim.libxpkg.log")
+
+local function sh_quote(value)
+    return "'" .. tostring(value):gsub("'", "'\\''") .. "'"
+end
+
+local function resolve_make()
+    local dep = pkginfo.build_dep("xim:make") or pkginfo.build_dep("make")
+    if dep and dep.bin then
+        local candidate = path.join(dep.bin, "make")
+        if os.isfile(candidate) then return candidate end
+    end
+    return "make"
+end
+
+local function resolve_cc()
+    if os.host() == "linux" and os.isfile("/usr/bin/gcc") then
+        return "/usr/bin/gcc"
+    end
+    if os.host() == "macosx" and os.isfile("/usr/bin/cc") then
+        return "/usr/bin/cc"
+    end
+    return "cc"
+end
+
+local function tail_lines(file, count)
+    local ok, content = pcall(io.readfile, file)
+    if not ok or not content then return "<log unavailable>" end
+    local lines = {}
+    for line in (tostring(content) .. "\n"):gmatch("(.-)\n") do
+        lines[#lines + 1] = line
+    end
+    local first = math.max(1, #lines - count + 1)
+    return table.concat(lines, "\n", first, #lines)
+end
+
+local function run(command, logf)
+    local ok, result = pcall(os.exec, string.format(
+        "bash -c %s", sh_quote(command .. " >> " .. sh_quote(logf) .. " 2>&1")))
+    if not ok or not result then
+        log.error("compat.gsl: build command failed; see %s\n%s",
+                  logf, tail_lines(logf, 80))
+        return false
+    end
+    return true
+end
+
+local function install_gsl()
+    local archive = pkginfo.install_file()
+    local source = archive and tostring(archive):replace(".tar.gz", "")
+                 or ("gsl-" .. pkginfo.version())
+    if not os.isdir(source) then
+        source = "gsl-" .. pkginfo.version()
+    end
+
+    local prefix = pkginfo.install_dir()
+    os.tryrm(prefix)
+    os.mv(source, prefix)
+    os.cd(prefix)
+
+    local logf = path.join(prefix, "mcpp_gsl_build.log")
+    local make = resolve_make()
+    local cc = resolve_cc()
+    local jobs = (os.default_njob and os.default_njob()) or 4
+    local configure = string.format(
+        "CC=%s CFLAGS='-std=c11' %s --disable-shared --enable-static "
+        .. "--disable-dependency-tracking "
+        .. "--prefix=%s --libdir=%s",
+        sh_quote(cc), "./configure", sh_quote(prefix),
+        sh_quote(path.join(prefix, "lib")))
+    if not run(configure, logf) then return false end
+    if not run(string.format("%s -j%d", sh_quote(make), jobs), logf) then
+        return false
+    end
+    if not run(string.format("%s install", sh_quote(make)), logf) then
+        return false
+    end
+
+    local required = {
+        path.join(prefix, "include", "gsl", "gsl_math.h"),
+        path.join(prefix, "include", "gsl", "gsl_cblas.h"),
+        path.join(prefix, "lib", "libgsl.a"),
+        path.join(prefix, "lib", "libgslcblas.a"),
+    }
+    for _, file in ipairs(required) do
+        if not os.isfile(file) then
+            log.error("compat.gsl: build did not produce %s; see %s", file, logf)
+            return false
+        end
+    end
+
+    io.writefile(path.join(prefix, "mcpp_gsl_anchor.c"),
+                 "int mcpp_compat_gsl_anchor(void) { return 0; }\n")
+    return true
+end
+
+function install()
+    if os.host() == "windows" then return true end
+    local ok, result = pcall(install_gsl)
+    if not ok then
+        log.error("compat.gsl install() failed: %s", tostring(result))
+        return false
+    end
+    return result
+end
diff --git a/tests/examples/gsl/mcpp.toml b/tests/examples/gsl/mcpp.toml
new file mode 100644
index 00000000..073e5a4a
--- /dev/null
+++ b/tests/examples/gsl/mcpp.toml
@@ -0,0 +1,12 @@
+[package]
+name    = "gsl-tests"
+version = "0.1.0"
+
+[indices]
+compat = { path = "../../.." }
+
+[target.'cfg(unix)'.dependencies.compat]
+gsl = "2.8"
+
+[target.'cfg(unix)'.build]
+cxxflags = ["-DHAVE_GSL=1"]
diff --git a/tests/examples/gsl/tests/gsl.cpp b/tests/examples/gsl/tests/gsl.cpp
new file mode 100644
index 00000000..fe72bd8f
--- /dev/null
+++ b/tests/examples/gsl/tests/gsl.cpp
@@ -0,0 +1,49 @@
+#ifdef HAVE_GSL
+
+#include <cmath>
+#include <cstdio>
+
+#include <gsl/gsl_blas.h>
+#include <gsl/gsl_cblas.h>
+#include <gsl/gsl_integration.h>
+#include <gsl/gsl_sf_bessel.h>
+
+namespace {
+
+double square(double x, void*) {
+    return x * x;
+}
+
+} // namespace
+
+int main() {
+    if (std::abs(gsl_sf_bessel_J0(0.0) - 1.0) > 1e-12) return 1;
+
+    double result = 0.0;
+    double error = 0.0;
+    gsl_function function;
+    function.function = &square;
+    function.params = nullptr;
+    gsl_integration_workspace* workspace = gsl_integration_workspace_alloc(100);
+    if (!workspace) return 2;
+    gsl_integration_qags(&function, 0.0, 1.0, 0.0, 1e-10, 100,
+                         workspace, &result, &error);
+    gsl_integration_workspace_free(workspace);
+    if (std::abs(result - 1.0 / 3.0) > 1e-8 || error > 1e-8) return 2;
+
+    const double left[2] = {1.0, 2.0};
+    const double right[2] = {3.0, 4.0};
+    const double product = cblas_ddot(2, left, 1, right, 1);
+    if (std::abs(product - 11.0) > 1e-12) return 3;
+
+    std::printf("compat.gsl: special functions, integration, and CBLAS ok\n");
+    return 0;
+}
+
+#else
+
+int main() {
+    return 0;
+}
+
+#endif