diff --git a/Cargo.lock b/Cargo.lock
index 44ad79c98..999bf17b6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -486,7 +486,7 @@ dependencies = [
 name = "bashkit-cpython-wasm"
 version = "0.18.2"
 dependencies = [
- "flate2",
+ "lzma-rs",
  "wasmtime",
 ]
 
@@ -977,7 +977,7 @@ version = "3.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "faf9468729b8cbcea668e36183cb69d317348c2e08e994829fb56ebfdfbaac34"
 dependencies = [
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -1250,6 +1250,21 @@ version = "0.135.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2b73d7e686f3518831f88ffe88be02c6c92be09930fc5ab90a3dfd9a4de3815e"
 
+[[package]]
+name = "crc"
+version = "3.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5eb8a2a1cd12ab0d987a5d5e825195d372001a4094a0376319d5a0ad71c1ba0d"
+dependencies = [
+ "crc-catalog",
+]
+
+[[package]]
+name = "crc-catalog"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "217698eaf96b4a3f0bc4f3662aaa55bdf913cd54d7204591faa790070c6d0853"
+
 [[package]]
 name = "crc32c"
 version = "0.6.8"
@@ -1706,7 +1721,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
 dependencies = [
  "libc",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -2953,6 +2968,16 @@ dependencies = [
  "tracing-subscriber",
 ]
 
+[[package]]
+name = "lzma-rs"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "297e814c836ae64db86b36cf2a557ba54368d03f6afcd7d947c266692f71115e"
+dependencies = [
+ "byteorder",
+ "crc",
+]
+
 [[package]]
 name = "mach2"
 version = "0.6.0"
@@ -4774,7 +4799,7 @@ dependencies = [
  "errno",
  "libc",
  "linux-raw-sys",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -4832,7 +4857,7 @@ dependencies = [
  "security-framework",
  "security-framework-sys",
  "webpki-root-certs",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -5574,10 +5599,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "32497e9a4c7b38532efcdebeef879707aa9f794296a4f0244f6f69e9bc8574bd"
 dependencies = [
  "fastrand",
- "getrandom 0.3.4",
+ "getrandom 0.4.3",
  "once_cell",
  "rustix",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -6664,7 +6689,7 @@ version = "0.1.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c2a7b1c03c876122aa43f3020e6c3c3ee5c05081c9a00739faf7503aeba10d22"
 dependencies = [
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
diff --git a/crates/bashkit-cpython-wasm/Cargo.toml b/crates/bashkit-cpython-wasm/Cargo.toml
index feb385aaa..05c016222 100644
--- a/crates/bashkit-cpython-wasm/Cargo.toml
+++ b/crates/bashkit-cpython-wasm/Cargo.toml
@@ -41,5 +41,6 @@ native = []
 
 [build-dependencies]
 wasmtime = { workspace = true, features = ["cranelift", "parallel-compilation"] }
-flate2 = { workspace = true }
+# Decodes artifacts/python.wasm.xz (pure Rust, build time only).
+lzma-rs = "0.3"
 
diff --git a/crates/bashkit-cpython-wasm/THIRD_PARTY_LICENSES.md b/crates/bashkit-cpython-wasm/THIRD_PARTY_LICENSES.md
index e9ffefa80..ef1723bb9 100644
--- a/crates/bashkit-cpython-wasm/THIRD_PARTY_LICENSES.md
+++ b/crates/bashkit-cpython-wasm/THIRD_PARTY_LICENSES.md
@@ -7,14 +7,14 @@ libraries statically linked into it (see `guest/build.sh` and
 
 | Component | Version | License | Where |
 |-----------|---------|---------|-------|
-| CPython (interpreter and stdlib) | 3.14.8 | Python-2.0 (PSF License Agreement and predecessors) | `artifacts/python.wasm.gz`, `artifacts/python314.zip` |
-| libmpdec (`decimal`) | bundled with CPython | BSD-2-Clause | `artifacts/python.wasm.gz` |
-| Expat (`pyexpat`, `xml.etree`) | bundled with CPython | MIT | `artifacts/python.wasm.gz` |
-| HACL* (`hashlib` md5/sha1/sha2/sha3/blake2, `hmac`) | bundled with CPython | MIT | `artifacts/python.wasm.gz` |
-| zlib | 1.3.1 | Zlib | `artifacts/python.wasm.gz` |
-| SQLite | 3.50.4 | Public domain (blessing) | `artifacts/python.wasm.gz` |
-| wasi-libc (WASI SDK 24) | 24 | Apache-2.0 WITH LLVM-exception OR Apache-2.0 OR MIT; musl parts MIT | `artifacts/python.wasm.gz` |
-| compiler-rt builtins (WASI SDK 24) | 24 | Apache-2.0 WITH LLVM-exception | `artifacts/python.wasm.gz` |
+| CPython (interpreter and stdlib) | 3.14.8 | Python-2.0 (PSF License Agreement and predecessors) | `artifacts/python.wasm.xz`, `artifacts/python314.zip` |
+| libmpdec (`decimal`) | bundled with CPython | BSD-2-Clause | `artifacts/python.wasm.xz` |
+| Expat (`pyexpat`, `xml.etree`) | bundled with CPython | MIT | `artifacts/python.wasm.xz` |
+| HACL* (`hashlib` md5/sha1/sha2/sha3/blake2, `hmac`) | bundled with CPython | MIT | `artifacts/python.wasm.xz` |
+| zlib | 1.3.1 | Zlib | `artifacts/python.wasm.xz` |
+| SQLite | 3.50.4 | Public domain (blessing) | `artifacts/python.wasm.xz` |
+| wasi-libc (WASI SDK 24) | 24 | Apache-2.0 WITH LLVM-exception OR Apache-2.0 OR MIT; musl parts MIT | `artifacts/python.wasm.xz` |
+| compiler-rt builtins (WASI SDK 24) | 24 | Apache-2.0 WITH LLVM-exception | `artifacts/python.wasm.xz` |
 
 The full license texts that require reproduction follow.
 
diff --git a/crates/bashkit-cpython-wasm/artifacts/MANIFEST b/crates/bashkit-cpython-wasm/artifacts/MANIFEST
index 6e6c86e5b..449af0507 100644
--- a/crates/bashkit-cpython-wasm/artifacts/MANIFEST
+++ b/crates/bashkit-cpython-wasm/artifacts/MANIFEST
@@ -3,5 +3,5 @@ wasi_sdk=24
 wasmtime_wizer=49.0.1
 zlib=1.3.1
 sqlite=sqlite-amalgamation-3500400
-31c43d757812151582ff3e274f0d9c65cf210064a46646a5a73a68704b83329b  python.wasm.gz
-7c1fec908a3c250e0591a4892f3dfbaa73e5c81798dfa33b1dc80e18931dbb74  python314.zip
+77058ae157db6f10e3fe9e73745147627a05bca03ee6a6c50a0a5f04ea1c7fa6  python.wasm.xz
+bfe72099bf1ab706b9de9a8856f509ac5db4fb1c86c29a49c622d37490ce388e  python314.zip
diff --git a/crates/bashkit-cpython-wasm/artifacts/python.wasm.gz b/crates/bashkit-cpython-wasm/artifacts/python.wasm.gz
deleted file mode 100644
index 58fdb7823..000000000
Binary files a/crates/bashkit-cpython-wasm/artifacts/python.wasm.gz and /dev/null differ
diff --git a/crates/bashkit-cpython-wasm/artifacts/python.wasm.xz b/crates/bashkit-cpython-wasm/artifacts/python.wasm.xz
new file mode 100644
index 000000000..875554ba6
Binary files /dev/null and b/crates/bashkit-cpython-wasm/artifacts/python.wasm.xz differ
diff --git a/crates/bashkit-cpython-wasm/artifacts/python314.zip b/crates/bashkit-cpython-wasm/artifacts/python314.zip
index 81abd3bb9..bda9a819d 100644
Binary files a/crates/bashkit-cpython-wasm/artifacts/python314.zip and b/crates/bashkit-cpython-wasm/artifacts/python314.zip differ
diff --git a/crates/bashkit-cpython-wasm/build.rs b/crates/bashkit-cpython-wasm/build.rs
index e117231bd..e1b2d539b 100644
--- a/crates/bashkit-cpython-wasm/build.rs
+++ b/crates/bashkit-cpython-wasm/build.rs
@@ -5,7 +5,6 @@
 //! product feature). Set `BASHKIT_CPYTHON_CWASM=/path/python.cwasm` to reuse a
 //! module precompiled by the same wasmtime version and configuration.
 
-use std::io::Read;
 use std::path::PathBuf;
 
 include!("src/config.rs");
@@ -13,7 +12,7 @@ include!("src/config.rs");
 fn main() {
     let manifest = PathBuf::from(std::env::var_os("CARGO_MANIFEST_DIR").unwrap());
     let out = PathBuf::from(std::env::var_os("OUT_DIR").unwrap()).join("python.cwasm");
-    let snapshot = manifest.join("artifacts/python.wasm.gz");
+    let snapshot = manifest.join("artifacts/python.wasm.xz");
     println!("cargo:rerun-if-changed={}", snapshot.display());
     println!("cargo:rerun-if-changed=src/config.rs");
     println!("cargo:rerun-if-env-changed=BASHKIT_CPYTHON_CWASM");
@@ -23,9 +22,11 @@ fn main() {
         return;
     }
 
+    // xz, not gzip: ~30% smaller, which keeps the crate under crates.io's
+    // 10 MiB cap with more modules preloaded. Decoded here only.
     let mut wasm = Vec::new();
-    flate2::read::GzDecoder::new(std::fs::File::open(&snapshot).expect("open snapshot"))
-        .read_to_end(&mut wasm)
+    let file = std::fs::File::open(&snapshot).expect("open snapshot");
+    lzma_rs::xz_decompress(&mut std::io::BufReader::new(file), &mut wasm)
         .expect("decompress snapshot");
     // The build script's own cfg is the host's; read the crate feature and
     // the cross-compilation target from Cargo instead.
diff --git a/crates/bashkit-cpython-wasm/guest/_bashkit_boot.py b/crates/bashkit-cpython-wasm/guest/_bashkit_boot.py
index 484b30ec6..70832f952 100644
--- a/crates/bashkit-cpython-wasm/guest/_bashkit_boot.py
+++ b/crates/bashkit-cpython-wasm/guest/_bashkit_boot.py
@@ -47,6 +47,8 @@
     # bashkit's own HTTP clients over the host bridge: preloaded so
     # `import requests` / `import httpx` cost nothing per call.
     "requests", "requests.utils", "httpx", "httpx2",
+    # Common in agent scripts and 0.1-0.5 s each to import on Pulley.
+    "urllib.request", "tomllib", "configparser", "xml.etree.ElementTree",
 )
 
 _USAGE = """\
diff --git a/crates/bashkit-cpython-wasm/guest/build.sh b/crates/bashkit-cpython-wasm/guest/build.sh
index ba1d9aab2..96688dca2 100755
--- a/crates/bashkit-cpython-wasm/guest/build.sh
+++ b/crates/bashkit-cpython-wasm/guest/build.sh
@@ -11,11 +11,12 @@
 # - The stdlib ships as one deflate-compressed zip of .py sources. The
 #   snapshot caches the zip directory, so the runtime must serve the exact
 #   same zip bytes; both artifacts are produced together by this script.
-# - Output is a gzip of the stripped snapshot plus the zip. The crate's
+# - Output is an xz of the stripped snapshot plus the zip (xz, not gzip:
+#   ~30% smaller, which keeps the crate under the crates.io 10 MiB cap). The crate's
 #   build.rs compiles the snapshot to Pulley bytecode ahead of time.
 #
 # Usage: guest/build.sh [WORK_DIR]
-# Requires: curl, tar, unzip, python3 (>=3.11), make, a C compiler for the
+# Requires: curl, tar, unzip, xz, python3 (>=3.11), make, a C compiler for the
 # native build Python. Everything else is downloaded into WORK_DIR.
 set -euo pipefail
 
@@ -130,11 +131,13 @@ cp -r "$HERE/requests" "$WORK/stdlib/requests"
     cd "$WORK/stdlib"
     # Not usable or not useful in a sandboxed, single-threaded, headless guest.
     rm -rf test idlelib tkinter turtledemo ensurepip venv pydoc_data turtle.py \
-        _pyrepl/__pycache__ curses dbm/gnu.py dbm/ndbm.py multiprocessing concurrent/futures/process.py
+        _pyrepl/__pycache__ curses mailbox.py dbm/gnu.py dbm/ndbm.py multiprocessing concurrent/futures/process.py
     # No FFI, TLS, sockets or TTY in the guest: these can never work.
     rm -rf ctypes ssl.py ftplib.py imaplib.py poplib.py smtplib.py socketserver.py \
         http/server.py wsgiref xmlrpc webbrowser.py _pyrepl pdb.py bdb.py pydoc.py \
         _aix_support.py _android_support.py _ios_support.py _osx_support.py
+    # Debugger stand-in: doctest imports pdb; breakpoint() prints a notice.
+    cp "$HERE/pdb.py" pdb.py
     # HTTP goes through the host's egress pipeline, not sockets
     # (_bashkit_http.py); http.client patches itself when first imported.
     printf '\n# bashkit: connections go through the host (see _bashkit_http).\nimport _bashkit_http\n_bashkit_http.patch_http_client(globals())\ndel _bashkit_http\n' >>http/client.py
@@ -185,7 +188,8 @@ case "$out" in
 esac
 
 mkdir -p "$CRATE/artifacts"
-gzip -9 -n -c "$WORK/python.wasm" >"$CRATE/artifacts/python.wasm.gz"
+rm -f "$CRATE/artifacts/python.wasm.gz"
+xz -9e -T1 -c "$WORK/python.wasm" >"$CRATE/artifacts/python.wasm.xz"
 cp "$ROOT/usr/local/lib/python314.zip" "$CRATE/artifacts/python314.zip"
 (
     cd "$CRATE/artifacts"
@@ -195,7 +199,7 @@ cp "$ROOT/usr/local/lib/python314.zip" "$CRATE/artifacts/python314.zip"
         echo "wasmtime_wizer=${WASMTIME_VERSION}"
         echo "zlib=${ZLIB_VERSION}"
         echo "sqlite=${SQLITE_AMALGAMATION}"
-        sha256sum python.wasm.gz python314.zip
+        sha256sum python.wasm.xz python314.zip
     } >MANIFEST
 )
 ls -la "$CRATE/artifacts"
diff --git a/crates/bashkit-cpython-wasm/guest/pdb.py b/crates/bashkit-cpython-wasm/guest/pdb.py
new file mode 100644
index 000000000..f3c980073
--- /dev/null
+++ b/crates/bashkit-cpython-wasm/guest/pdb.py
@@ -0,0 +1,46 @@
+"""pdb stand-in for bashkit's CPython guest.
+
+There is no interactive terminal in the sandbox, so the real debugger is
+not shipped. This stub keeps modules that import pdb (doctest, unittest
+helpers) working: `breakpoint()` / `pdb.set_trace()` print a notice and
+continue; `pdb.run*` raise RuntimeError.
+"""
+
+import sys
+
+_MSG = "pdb: debugger not available in the bashkit sandbox; continuing"
+
+
+class Pdb:
+    """Constructible (doctest creates one per run); debugging is a no-op."""
+
+    def __init__(self, *args, **kwargs):
+        pass
+
+    def set_trace(self, *args, **kwargs):
+        print(_MSG, file=sys.stderr)
+
+    def reset(self):
+        pass
+
+    def set_continue(self):
+        pass
+
+
+def set_trace(*args, header=None, **kwargs):
+    print(_MSG, file=sys.stderr)
+
+
+def post_mortem(*args, **kwargs):
+    print(_MSG, file=sys.stderr)
+
+
+def pm():
+    post_mortem()
+
+
+def run(*args, **kwargs):
+    raise RuntimeError("pdb is not available in the bashkit sandbox")
+
+
+runeval = runcall = runctx = run
diff --git a/crates/bashkit/docs/cpython.md b/crates/bashkit/docs/cpython.md
index 8043c7d23..a3f171b5f 100644
--- a/crates/bashkit/docs/cpython.md
+++ b/crates/bashkit/docs/cpython.md
@@ -203,7 +203,8 @@ with httpx.Client(base_url="https://api.example.com", headers={"X-Key": "..."})
   `_hashlib` (OpenSSL), `tkinter`, `curses`, `readline`, `dbm.gnu` are not
   built. `hashlib` still provides md5, sha1, sha2, sha3 and blake2.
 - **No interactive mode**: `python3` with no program reads one from stdin;
-  there is no REPL, and `pdb` and `pydoc` (`help()`) are not shipped.
+  there is no REPL, `pydoc` (`help()`) is not shipped, and `breakpoint()`
+  prints a notice and continues (no debugger).
 - **Stdlib is bytecode only**: tracebacks through stdlib code show no source
   line, and `inspect.getsource()` fails on stdlib objects. Your own code
   keeps full tracebacks. Non-HTTP network clients and servers (`smtplib`,
diff --git a/crates/bashkit/fuzz/Cargo.lock b/crates/bashkit/fuzz/Cargo.lock
index 7b20e20ff..25aa40eb6 100644
--- a/crates/bashkit/fuzz/Cargo.lock
+++ b/crates/bashkit/fuzz/Cargo.lock
@@ -141,7 +141,7 @@ dependencies = [
 name = "bashkit-cpython-wasm"
 version = "0.18.2"
 dependencies = [
- "flate2",
+ "lzma-rs",
  "wasmtime",
 ]
 
@@ -241,6 +241,12 @@ dependencies = [
  "allocator-api2",
 ]
 
+[[package]]
+name = "byteorder"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1fd0f2584146f6f2ef48085050886acf353beff7305ebd1ae69500e27c67f64b"
+
 [[package]]
 name = "bytes"
 version = "1.12.1"
@@ -533,6 +539,21 @@ version = "0.135.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2b73d7e686f3518831f88ffe88be02c6c92be09930fc5ab90a3dfd9a4de3815e"
 
+[[package]]
+name = "crc"
+version = "3.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5eb8a2a1cd12ab0d987a5d5e825195d372001a4094a0376319d5a0ad71c1ba0d"
+dependencies = [
+ "crc-catalog",
+]
+
+[[package]]
+name = "crc-catalog"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "217698eaf96b4a3f0bc4f3662aaa55bdf913cd54d7204591faa790070c6d0853"
+
 [[package]]
 name = "crc32fast"
 version = "1.5.0"
@@ -1217,6 +1238,16 @@ version = "0.4.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0ceec5bc11778974d1bcb055b18002eba7f4b3518b6a0081b3af5f21666da9ad"
 
+[[package]]
+name = "lzma-rs"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "297e814c836ae64db86b36cf2a557ba54368d03f6afcd7d947c266692f71115e"
+dependencies = [
+ "byteorder",
+ "crc",
+]
+
 [[package]]
 name = "mach2"
 version = "0.6.0"
diff --git a/crates/bashkit/tests/integration/cpython_http_tests.rs b/crates/bashkit/tests/integration/cpython_http_tests.rs
index 48dbf83ec..fba67a246 100644
--- a/crates/bashkit/tests/integration/cpython_http_tests.rs
+++ b/crates/bashkit/tests/integration/cpython_http_tests.rs
@@ -743,7 +743,7 @@ except requests.ConnectionError as e:
 import sys
 before = set(sys.modules)
 import requests, httpx, httpx2
-heavy = {"http.client", "email", "urllib3", "ssl", "http.cookiejar"}
+heavy = {"urllib3", "ssl", "http.cookiejar", "charset_normalizer"}
 print(sorted(set(sys.modules) - before), sorted(heavy & set(sys.modules)))
 "#,
         )
diff --git a/crates/bashkit/tests/integration/cpython_integration_tests.rs b/crates/bashkit/tests/integration/cpython_integration_tests.rs
index e77c8b7ac..5377549c4 100644
--- a/crates/bashkit/tests/integration/cpython_integration_tests.rs
+++ b/crates/bashkit/tests/integration/cpython_integration_tests.rs
@@ -535,7 +535,7 @@ async fn stdlib_is_bytecode_only() {
     let out = ok("python3 -c '
 import email.message, http.client, xml.dom.minidom, json
 print(json.__file__.endswith(\".pyc\"), email.message.__file__.endswith(\".pyc\"))
-for m in (\"ctypes\", \"ssl\", \"smtplib\", \"pdb\", \"pydoc\", \"_pydecimal\"):
+for m in (\"ctypes\", \"ssl\", \"smtplib\", \"bdb\", \"pydoc\", \"_pydecimal\", \"mailbox\"):
     try:
         __import__(m)
         print(m, \"present\")
@@ -548,6 +548,34 @@ print(decimal.Decimal(\"1.10\") + 1, datetime.datetime.strptime(\"2020\", \"%Y\"
     assert_eq!(out, "True True\n2.10 2020\n");
 }
 
+/// The real debugger is not shipped; a stand-in keeps doctest importable and
+/// makes `breakpoint()` print a notice and continue.
+#[tokio::test]
+async fn doctest_works_and_breakpoint_continues() {
+    let r = Bash::builder()
+        .cpython()
+        .build()
+        .exec(
+            "cat > /m.py <<'EOF'
+def add(a, b):
+    \"\"\"
+    >>> add(1, 2)
+    3
+    \"\"\"
+    return a + b
+EOF
+cd / && python3 -c 'import doctest, m; print(doctest.testmod(m)); breakpoint(); print(\"after\")'",
+        )
+        .await
+        .unwrap();
+    assert_eq!(
+        r.stdout, "TestResults(failed=0, attempted=1)\nafter\n",
+        "{}",
+        r.stderr
+    );
+    assert!(r.stderr.contains("debugger not available"), "{}", r.stderr);
+}
+
 #[tokio::test]
 async fn local_modules_are_reimported_each_call() {
     let out = ok(
diff --git a/knowledge/log.md b/knowledge/log.md
index a7a311d0a..49db29071 100644
--- a/knowledge/log.md
+++ b/knowledge/log.md
@@ -4,6 +4,7 @@
 
 * **Fix**: `${x#pat}`/`${x%pat}` follow the glob grammar. A lone `*` matches empty for the short forms (`${x#*}` and `${x%*}` keep `x`; they dropped a character), and patterns with `?` or several `*` (`${x%?}`, `${p#*/*/}`, `${p##*.*.}`) now match instead of being compared as literal text. Single-`*` patterns keep their linear fast path.
 * **Fix**: Quoted or escaped glob characters are literal everywhere. `echo a\*`, `a"*"` and `a'?'` no longer glob; `case`/`[[ == ]]` patterns match `"$x"`, `'a*'`, `a\*` and `\[s\]` literally; `"*"zz*` with no match prints `*zz*` (escapes no longer leak); `"$x"zz*` no longer reads `$xzz`; `'a'$x` expands and `'a'*` globs; `a{1,2}"*"` still brace-expands. The lexer escapes quoted glob characters in mixed words (the existing `QuotedGlobWord` convention, now with quote markers); `expand_word` returns unescaped text for non-glob uses; patterns use `expand_pattern_word`. Known gap: data from an unquoted expansion inside such a word loses `\` before glob characters when nothing matches.
+* **Perf**: The CPython snapshot ships as xz (4.99 MB, was ~6.7 MB as gzip; decoded by `lzma-rs` in build.rs). The room went to preloading `urllib.request` (http.client, email), `tomllib`, `configparser` and `xml.etree.ElementTree`: their imports went from 0.1-0.47 s per call to ~0; `print(1)` unchanged at ~4.1 ms, first call ~20 ms. `doctest` works again (a `pdb` stand-in; `breakpoint()` prints a notice), `mailbox` dropped. See [CPython WebAssembly Runtime](runtimes/cpython-wasm.md#startup-is-the-product-constraint).
 * **Feature**: `import requests`, `import httpx` and `import httpx2` work in CPython. They are bashkit's own compact implementations of the common API over the HTTP bridge, preloaded in the snapshot (import cost ~0 vs ~3.1 s for vendored upstream requests). http.client read timeouts now surface from `getresponse()`. L-CPY-003 updated, L-CPY-010 added. See [CPython WebAssembly Runtime](runtimes/cpython-wasm.md#requests-and-httpx-bashkits-own-modules).
 * **Fix**: A backslash outside quotes keeps `$` and `` ` `` literal. `echo \$HOME` printed the home directory; it now prints `$HOME`, as do `a\$x`, `\${x}` and `x=\$y` (the lexer emits the same NUL literal marker as quoted `"\$"`). Found while working gap telemetry.
 * **Fix**: `$'\x1e'` and `$'\x1f'` bytes (record/unit separators) are kept as data. They collided with the lexer's quote-boundary markers and were silently dropped, which broke the common `SEP=$'\x1f'` composite-key idiom for associative arrays (`v["$section"$'\x1f'"$key"]`). Decoded ANSI-C content now NUL-escapes those bytes like `$`. Found by gap telemetry (`config_ini_merge` replay printed nothing).
diff --git a/knowledge/operations/dependencies.md b/knowledge/operations/dependencies.md
index bb37605fd..f31bca772 100644
--- a/knowledge/operations/dependencies.md
+++ b/knowledge/operations/dependencies.md
@@ -160,6 +160,13 @@ worth keeping so the question does not get re-litigated from scratch.
   of `Quotable`), but they are imported by *generated* coreutils-port files, so
   removal means carrying rewrite rules in the porter. Low return.
 
+## Build-only dependencies of `bashkit-cpython-wasm`
+
+- `lzma-rs` (pure Rust, MIT) decodes the xz-compressed CPython snapshot in
+  `build.rs`. Never linked into a binary. xz keeps the crate under the
+  crates.io 10 MiB cap with more modules preloaded (see
+  [CPython WebAssembly Runtime](../runtimes/cpython-wasm.md)).
+
 ## Vendored crates
 
 - **`jaq-json`** is vendored into the jq builtin so its value operations can
diff --git a/knowledge/operations/limitations.md b/knowledge/operations/limitations.md
index 9dc6fcac8..758eb2771 100644
--- a/knowledge/operations/limitations.md
+++ b/knowledge/operations/limitations.md
@@ -134,7 +134,7 @@ Boundaries of the WebAssembly CPython guest; see
 | L-CPY-007 | No interactive REPL; `python3` with no program reads one from stdin | No TTY inside the sandbox | stance |
 | L-CPY-008 | Guest memory per call is capped at 1 GiB even if `max_memory` is higher | Pooled instance slots have a fixed maximum size | [CPython WebAssembly Runtime](../runtimes/cpython-wasm.md) |
 | L-CPY-010 | `requests` and `httpx` are subsets: no retries, proxies, client certificates, HTTP/2, digest auth, streaming uploads or OPTIONS; bodies are buffered; `AsyncClient` requests run sequentially | Upstream packages cost ~3 s per call to import on Pulley; the subset is preloaded in the snapshot and costs nothing | `requests_lib`, `httpx_lib` in `cpython_http_tests` |
-| L-CPY-009 | Stdlib ships as bytecode only: tracebacks show no source line for stdlib frames, `inspect.getsource()` fails on stdlib objects. Modules that cannot work in the guest are not shipped: `ctypes`, `ssl`, `ftplib`, `imaplib`, `poplib`, `smtplib`, `socketserver`, `http.server`, `wsgiref`, `xmlrpc`, `webbrowser`, `pdb`, `bdb`, `pydoc` (so `help()`), `_pyrepl` | Compiling source on Pulley costs seconds per import; sources would push the crate past the crates.io 10 MiB cap. No FFI, TLS, sockets or TTY exist | `stdlib_is_bytecode_only` (cpython_integration_tests) |
+| L-CPY-009 | Stdlib ships as bytecode only: tracebacks show no source line for stdlib frames, `inspect.getsource()` fails on stdlib objects. Modules that cannot work in the guest are not shipped: `ctypes`, `ssl`, `ftplib`, `imaplib`, `poplib`, `smtplib`, `socketserver`, `http.server`, `wsgiref`, `xmlrpc`, `webbrowser`, `bdb`, `pydoc` (so `help()`), `_pyrepl`, `mailbox`; `pdb` is a stand-in (`breakpoint()` prints a notice and continues, doctest works) | Compiling source on Pulley costs seconds per import; sources would push the crate past the crates.io 10 MiB cap. No FFI, TLS, sockets or TTY exist | `stdlib_is_bytecode_only` (cpython_integration_tests) |
 
 ## Text Processing
 
diff --git a/knowledge/operations/release-process.md b/knowledge/operations/release-process.md
index 5b3c8739b..5c75357a5 100644
--- a/knowledge/operations/release-process.md
+++ b/knowledge/operations/release-process.md
@@ -82,7 +82,7 @@ silently failed.
    `cargo publish` packaging step, missing files, version drift):
    - `cargo publish --dry-run -p bashkit-cpython-wasm` must succeed and the
      `.crate` must stay under crates.io's 10 MiB limit (it embeds the CPython
-     snapshot; ~9.8 MiB after the requests/httpx modules, 236 KB under the cap). `bashkit` depends on the same version
+     snapshot as xz; ~8.2 MiB with requests/httpx and urllib.request preloaded). `bashkit` depends on the same version
      of it, so `publish.yml` publishes it first and the `bashkit` dry-run only
      resolves once that version is live.
    - `cargo publish --dry-run -p bashkit` must succeed. Package
diff --git a/knowledge/runtimes/cpython-wasm.md b/knowledge/runtimes/cpython-wasm.md
index 8d7403bb0..6f0d3fe61 100644
--- a/knowledge/runtimes/cpython-wasm.md
+++ b/knowledge/runtimes/cpython-wasm.md
@@ -71,7 +71,20 @@ call:
    (`import http.client` 7.2 s, now ~0.5 s); sources plus bytecode would
    exceed the crates.io 10 MiB crate cap. Modules that cannot work in the
    guest (FFI, TLS, sockets, TTY) and pure-Python twins of C modules are
-   not shipped (L-CPY-009).
+   not shipped (L-CPY-009). `pdb` is a stand-in (`guest/pdb.py`): doctest
+   imports it, `breakpoint()` prints a notice and continues.
+9. **xz snapshot artifact**: `artifacts/python.wasm.xz` (xz -9e) instead of
+   gzip: 4.99 MB vs ~6.7 MB for the same snapshot. `build.rs` decodes it
+   with `lzma-rs` (pure Rust build-dependency; ~2.5 s in a debug build
+   script, nothing at run time). Rejected: zstd/brotli (C or no pure-Rust
+   encoder parity) and splitting the stdlib into a second crate (single
+   companion crate is a product decision).
+10. **Preload budget**: what the snapshot imports is chosen by per-call
+   import cost on Pulley against crate size. Preloaded beyond the core set:
+   bashkit's requests/httpx, `urllib.request` (with http.client and email,
+   0.47 s per call before), `tomllib`, `configparser`,
+   `xml.etree.ElementTree` (0.1-0.12 s each). Each costs snapshot bytes,
+   not per-call time (`print(1)` stayed ~4.1 ms). `mailbox` is not shipped.
 
 Measured on a 4-vCPU x86-64 VM (see `criterion-python-*` results under
 `crates/bashkit/benches/results/`): first `python3` in a fresh process
@@ -80,7 +93,9 @@ Measured on a 4-vCPU x86-64 VM (see `criterion-python-*` results under
 CPU-bound Python is ~4-30x slower than Monty. 1024 concurrent tenants × 4
 calls: 0 failures, ~165 calls/s on 4 vCPUs, 3.0 GB peak RSS (2026-10-07,
 after immortal objects; was ~90 calls/s, 4.7 GB). Importing a module outside
-the snapshot costs ~0.27 s (`email.message`) to ~0.46 s (`http.client`).
+the snapshot costs ~0.1-0.2 s (`unittest` 0.2 s, `zoneinfo` 0.11 s,
+`tarfile` 0.1 s); `email`, `http.client` and `urllib.request` are preloaded
+(~0 per call, was 0.27-0.47 s).
 
 ### Native code (opt-in, `cpython-native`)
 
@@ -262,7 +277,7 @@ CI: the Test job runs `cargo test -p bashkit --features cpython,http_client
 `crates/bashkit-cpython-wasm/guest/build.sh [WORK_DIR]` downloads pinned
 sources (CPython, WASI SDK, wasmtime CLI for `wizer`, zlib, sqlite), builds,
 snapshots, smoke-tests with the reference runtime and rewrites `artifacts/`
-(`python.wasm.gz`, `python314.zip`, `MANIFEST` with checksums). Commit all
+(`python.wasm.xz`, `python314.zip`, `MANIFEST` with checksums). Commit all
 three together. Changing `engine_config()` or the wasmtime version requires
 no guest rebuild; `build.rs` recompiles the `.cwasm`.
 
diff --git a/supply-chain/config.toml b/supply-chain/config.toml
index a7b15539c..85b1cc318 100644
--- a/supply-chain/config.toml
+++ b/supply-chain/config.toml
@@ -388,6 +388,14 @@ criteria = "safe-to-deploy"
 version = "0.3.0"
 criteria = "safe-to-deploy"
 
+[[exemptions.crc]]
+version = "3.4.0"
+criteria = "safe-to-deploy"
+
+[[exemptions.crc-catalog]]
+version = "2.5.0"
+criteria = "safe-to-deploy"
+
 [[exemptions.crc32c]]
 version = "0.6.8"
 criteria = "safe-to-deploy"
@@ -1017,6 +1025,10 @@ criteria = "safe-to-deploy"
 version = "0.7.2"
 criteria = "safe-to-deploy"
 
+[[exemptions.lzma-rs]]
+version = "0.3.0"
+criteria = "safe-to-deploy"
+
 [[exemptions.mach2]]
 version = "0.6.0"
 criteria = "safe-to-deploy"