diff --git a/CLAUDE.md b/CLAUDE.md
index 9b08a61640..b1bb8eb2a3 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -8,7 +8,7 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 Perry is a native TypeScript compiler written in Rust that compiles TypeScript source code directly to native executables. It uses SWC for TypeScript parsing and LLVM for code generation.
 
-**Current Version:** 0.5.1571
+**Current Version:** 0.5.1572
 
 
 ## TypeScript Parity Status
diff --git a/Cargo.lock b/Cargo.lock
index 7142aaaa5d..3e72f191c2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5583,7 +5583,7 @@ checksum = "1542e48011813fbdf3c075da4a4ed53ee93c816eef62e36eb5064a6fd2be10a5"
 
 [[package]]
 name = "perry"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "anyhow",
  "base64 0.22.1",
@@ -5647,7 +5647,7 @@ dependencies = [
 
 [[package]]
 name = "perry-api-manifest"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-dispatch",
  "serde",
@@ -5655,7 +5655,7 @@ dependencies = [
 
 [[package]]
 name = "perry-audio-miniaudio"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "cc",
  "libc",
@@ -5664,7 +5664,7 @@ dependencies = [
 
 [[package]]
 name = "perry-codegen"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "aho-corasick",
  "anyhow",
@@ -5681,7 +5681,7 @@ dependencies = [
 
 [[package]]
 name = "perry-codegen-arkts"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "anyhow",
  "perry-hir",
@@ -5689,7 +5689,7 @@ dependencies = [
 
 [[package]]
 name = "perry-codegen-glance"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "anyhow",
  "perry-hir",
@@ -5697,7 +5697,7 @@ dependencies = [
 
 [[package]]
 name = "perry-codegen-js"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "anyhow",
  "perry-dispatch",
@@ -5706,7 +5706,7 @@ dependencies = [
 
 [[package]]
 name = "perry-codegen-swiftui"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "anyhow",
  "perry-hir",
@@ -5714,7 +5714,7 @@ dependencies = [
 
 [[package]]
 name = "perry-codegen-wasm"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "anyhow",
  "base64 0.22.1",
@@ -5726,7 +5726,7 @@ dependencies = [
 
 [[package]]
 name = "perry-codegen-wear-tiles"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "anyhow",
  "perry-hir",
@@ -5734,7 +5734,7 @@ dependencies = [
 
 [[package]]
 name = "perry-container-compose"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "async-trait",
  "clap",
@@ -5758,14 +5758,14 @@ dependencies = [
 
 [[package]]
 name = "perry-container-e2e"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "anyhow",
 ]
 
 [[package]]
 name = "perry-diagnostics"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "serde",
  "serde_json",
@@ -5773,7 +5773,7 @@ dependencies = [
 
 [[package]]
 name = "perry-dispatch"
-version = "0.5.1571"
+version = "0.5.1572"
 
 [[package]]
 name = "perry-doc-fixture-my-bindings"
@@ -5784,7 +5784,7 @@ dependencies = [
 
 [[package]]
 name = "perry-doc-tests"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "anyhow",
  "clap",
@@ -5799,7 +5799,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-ads"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "block2",
  "objc2",
@@ -5809,7 +5809,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-argon2"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "argon2",
  "perry-ffi",
@@ -5818,7 +5818,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-axios"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-ffi",
  "reqwest",
@@ -5827,7 +5827,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-bcrypt"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "bcrypt",
  "perry-ffi",
@@ -5835,7 +5835,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-better-sqlite3"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-ffi",
  "rusqlite",
@@ -5843,7 +5843,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-cheerio"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-ffi",
  "scraper",
@@ -5851,7 +5851,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-commander"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-ffi",
  "perry-runtime",
@@ -5859,7 +5859,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-cron"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "chrono",
  "cron",
@@ -5869,7 +5869,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-dayjs"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "chrono",
  "perry-ffi",
@@ -5877,7 +5877,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-decimal"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-ffi",
  "rust_decimal",
@@ -5885,7 +5885,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-dotenv"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-ffi",
  "serde_json",
@@ -5893,7 +5893,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-ethers"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-ffi",
  "rand 0.10.2",
@@ -5901,7 +5901,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-events"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-ffi",
  "perry-runtime",
@@ -5909,14 +5909,14 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-exponential-backoff"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-ffi",
 ]
 
 [[package]]
 name = "perry-ext-fastify"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "bytes",
  "http-body-util",
@@ -5933,7 +5933,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-fetch"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "bytes",
  "lazy_static",
@@ -5946,7 +5946,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-http"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "base64 0.22.1",
  "bytes",
@@ -5978,7 +5978,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-ioredis"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "lazy_static",
  "perry-ffi",
@@ -5988,7 +5988,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-jsonwebtoken"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "base64 0.22.1",
  "jsonwebtoken",
@@ -5999,7 +5999,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-lru-cache"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "lru",
  "perry-ffi",
@@ -6008,7 +6008,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-moment"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "chrono",
  "perry-ffi",
@@ -6016,7 +6016,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-mongodb"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "bson",
  "futures-util",
@@ -6028,7 +6028,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-mysql2"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "chrono",
  "perry-ffi",
@@ -6040,7 +6040,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-nanoid"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "nanoid",
  "perry-ffi",
@@ -6049,7 +6049,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-net"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "bytes",
  "perry-ffi",
@@ -6064,7 +6064,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-node-forge"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "const-oid 0.10.2",
  "der 0.8.1",
@@ -6083,7 +6083,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-nodemailer"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "lettre",
  "perry-ffi",
@@ -6093,7 +6093,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-parcel-watcher"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "notify",
  "perry-ffi",
@@ -6105,7 +6105,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-pdf"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-ffi",
  "printpdf",
@@ -6113,7 +6113,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-pg"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-ffi",
  "sqlx",
@@ -6122,7 +6122,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-qs"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-ffi",
  "perry-runtime",
@@ -6131,7 +6131,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-ratelimit"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "governor",
  "perry-ffi",
@@ -6139,7 +6139,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-sharp"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "fast_image_resize",
  "image",
@@ -6150,7 +6150,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-streams"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "lazy_static",
  "perry-ffi",
@@ -6159,7 +6159,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-typescript"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "anyhow",
  "perry-ffi",
@@ -6179,7 +6179,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-undici"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-ffi",
  "perry-runtime",
@@ -6188,7 +6188,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-uuid"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-ffi",
  "uuid",
@@ -6196,7 +6196,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-validator"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-ffi",
  "perry-validation",
@@ -6205,7 +6205,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-ws"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "futures-util",
  "lazy_static",
@@ -6218,7 +6218,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-zlib"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "brotli",
  "flate2",
@@ -6228,7 +6228,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ffi"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "dashmap 6.2.1",
  "once_cell",
@@ -6238,7 +6238,7 @@ dependencies = [
 
 [[package]]
 name = "perry-hir"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "anyhow",
  "perry-api-manifest",
@@ -6258,11 +6258,11 @@ dependencies = [
 
 [[package]]
 name = "perry-native-registration"
-version = "0.5.1571"
+version = "0.5.1572"
 
 [[package]]
 name = "perry-parser"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "anyhow",
  "perry-diagnostics",
@@ -6275,7 +6275,7 @@ dependencies = [
 
 [[package]]
 name = "perry-perex"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perex",
  "regex",
@@ -6283,7 +6283,7 @@ dependencies = [
 
 [[package]]
 name = "perry-runtime"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "ahash",
  "base64 0.22.1",
@@ -6341,14 +6341,14 @@ dependencies = [
 
 [[package]]
 name = "perry-runtime-static"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-runtime",
 ]
 
 [[package]]
 name = "perry-stdlib"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "aes 0.8.4",
  "aes 0.9.1",
@@ -6437,21 +6437,21 @@ dependencies = [
 
 [[package]]
 name = "perry-stdlib-static"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-stdlib",
 ]
 
 [[package]]
 name = "perry-transform"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "perry-hir",
 ]
 
 [[package]]
 name = "perry-ui"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "dirs",
  "perry-ffi",
@@ -6461,7 +6461,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-android"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "base64 0.22.1",
  "jni",
@@ -6476,7 +6476,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-geisterhand"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "rand 0.10.2",
  "serde",
@@ -6486,7 +6486,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-gtk4"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "base64 0.22.1",
  "cairo-rs 0.22.9",
@@ -6509,7 +6509,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-ios"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "base64 0.22.1",
  "block2",
@@ -6526,7 +6526,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-macos"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "base64 0.22.1",
  "block2",
@@ -6543,7 +6543,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-model"
-version = "0.5.1571"
+version = "0.5.1572"
 
 [[package]]
 name = "perry-ui-test"
@@ -6554,11 +6554,11 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-testkit"
-version = "0.5.1571"
+version = "0.5.1572"
 
 [[package]]
 name = "perry-ui-tvos"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "base64 0.22.1",
  "block2",
@@ -6575,7 +6575,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-visionos"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "base64 0.22.1",
  "block2",
@@ -6592,7 +6592,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-watchos"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "block2",
  "libc",
@@ -6606,7 +6606,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-windows"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "base64 0.22.1",
  "libc",
@@ -6625,7 +6625,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-windows-winui"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "base64 0.22.1",
  "libc",
@@ -6638,7 +6638,7 @@ dependencies = [
 
 [[package]]
 name = "perry-updater"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "anyhow",
  "base64 0.22.1",
@@ -6653,7 +6653,7 @@ dependencies = [
 
 [[package]]
 name = "perry-validation"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "idna",
  "regex",
@@ -6663,7 +6663,7 @@ dependencies = [
 
 [[package]]
 name = "perry-wasm-host"
-version = "0.5.1571"
+version = "0.5.1572"
 dependencies = [
  "wasmi",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index 1703902254..3735806113 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -338,7 +338,7 @@ codegen-units = 1
 codegen-units = 1
 
 [workspace.package]
-version = "0.5.1571"
+version = "0.5.1572"
 edition = "2021"
 license = "MIT"
 repository = "https://github.com/PerryTS/perry"
diff --git a/changelog.d/10279-deferred-cycle-init.md b/changelog.d/10279-deferred-cycle-init.md
new file mode 100644
index 0000000000..a8aff81229
--- /dev/null
+++ b/changelog.d/10279-deferred-cycle-init.md
@@ -0,0 +1,11 @@
+Initialize the cycle partner of a module that is reached only through a dynamic
+`import()`. Perry drops init-call back-edges from a module's `__init` wrapper so
+that a cycle member the entry's eager init loop already ran is not re-entered
+early, but that loop skips Deferred modules, so dropping the edge to one left it
+with no caller at all: its body never ran and every export it assigns at run time
+stayed undefined, surfacing as `TypeError: value is not a function` on the first
+call through such a binding. The positional drop now applies only to Eager deps.
+An Eager module's static imports are themselves statically reachable from the
+entry and so are Eager, which is why the ordering this rule protects is
+unaffected, and the existing per-module init guard keeps the extra call
+idempotent and cycle-safe.
diff --git a/changelog.d/10280-proxy-value-shapes.md b/changelog.d/10280-proxy-value-shapes.md
new file mode 100644
index 0000000000..195cd7b323
--- /dev/null
+++ b/changelog.d/10280-proxy-value-shapes.md
@@ -0,0 +1,24 @@
+Fix Proxy values in `Array.from` and dynamic `RequestInit.headers` (#10270,
+#10274; OpenCode bring-up tracker #10107).
+
+- Route array proxies through iterator materialization before inspecting heap
+  headers, including mapped `Array.from`, Headers iterable pairs, call spread,
+  and collection constructors. Preserve the proxy receiver when a get trap
+  forwards the default iterator, and safely dispatch array-like proxy indices.
+  Keep concat on trapped indexed reads, preserving
+  holes and ignoring a custom iterator.
+- Convert dynamic Request header records/iterables with
+  `js_headers_init_from_value`; retain the existing inline literal-header path.
+- Keep proxy registry lookups behind the existing proxy-id band predicate;
+  Array.from checks only within its existing small-handle branch.
+- Add compiled regression probes for both issue reproductions, nested proxies,
+  get/ownKeys traps, custom iterators, mapped conversion, and sibling consumers.
+
+Read a Proxy source’s iterator method once before constructing the result, and
+cache the iterator’s next method. Keep the method, iterator, intermediate values,
+and pending mapping errors rooted across user callbacks and iterator closing.
+
+Pass an existing Headers handle straight to the Request constructor, which
+already clones its entries, instead of copying it into a temporary Headers
+store first. Records, iterables, Proxies, `undefined` and `null` still take the
+full conversion path.
diff --git a/crates/perry-codegen/src/lower_call/builtin.rs b/crates/perry-codegen/src/lower_call/builtin.rs
index 3996ef9dab..236b982c67 100644
--- a/crates/perry-codegen/src/lower_call/builtin.rs
+++ b/crates/perry-codegen/src/lower_call/builtin.rs
@@ -1374,7 +1374,8 @@ pub(super) fn lower_builtin_new<'a>(
                                 if let Some(hprops) = extract_options_fields(ctx, vexpr) {
                                     headers_handle = build_headers_from_object(ctx, &hprops)?;
                                 } else {
-                                    headers_handle = lower_expr(ctx, vexpr)?;
+                                    headers_handle =
+                                        super::options::build_headers_from_value(ctx, vexpr)?;
                                 }
                             }
                             "referrer" => {
diff --git a/crates/perry-codegen/src/lower_call/options/mod.rs b/crates/perry-codegen/src/lower_call/options/mod.rs
index 281d1d9fcb..4574cbaa12 100644
--- a/crates/perry-codegen/src/lower_call/options/mod.rs
+++ b/crates/perry-codegen/src/lower_call/options/mod.rs
@@ -67,6 +67,23 @@ pub(in crate::lower_call) fn build_headers_from_object(
     })
 }
 
+/// Convert a dynamic HeadersInit with the same helper as `new Headers(init)`.
+/// The literal path stays in `build_headers_from_object`; a runtime value is
+/// not necessarily a Headers registry handle (it may be a record or iterable).
+pub(in crate::lower_call) fn build_headers_from_value(
+    ctx: &mut FnCtx<'_>,
+    init: &Expr,
+) -> Result<String> {
+    with_rooted_group(ctx, 1, |ctx, group| {
+        let value = lower_expr(ctx, init)?;
+        let h = ctx
+            .block()
+            .call(DOUBLE, "js_headers_from_value", &[(DOUBLE, &value)]);
+        let h_root = group.adopt_emitted(ctx, Repr::Boxed, &h, true);
+        Ok(group.reread_emitted(ctx, h_root))
+    })
+}
+
 /// Phase 3 compat: extract `{key: value, ...}` pairs from an options
 /// argument in a form that works whether the options literal reached us
 /// as a plain `Expr::Object(props)` (pre-Phase-3 / spread/dynamic shapes)
diff --git a/crates/perry-codegen/src/runtime_decls/strings_part2.rs b/crates/perry-codegen/src/runtime_decls/strings_part2.rs
index 14d9ac9516..0316269426 100644
--- a/crates/perry-codegen/src/runtime_decls/strings_part2.rs
+++ b/crates/perry-codegen/src/runtime_decls/strings_part2.rs
@@ -970,6 +970,7 @@ pub(crate) fn declare_phase_b_strings_part2(module: &mut LlModule) {
     module.declare_function("js_response_body_init_ptr", I64, &[DOUBLE]);
     // new Headers() -> f64
     module.declare_function("js_headers_new", DOUBLE, &[]);
+    module.declare_function("js_headers_from_value", DOUBLE, &[DOUBLE]);
     // headers.set(handle_f64, key_ptr, val_ptr) -> f64 (undefined-tag)
     module.declare_function("js_headers_set", DOUBLE, &[DOUBLE, I64, I64]);
     // headers.append(handle_f64, key_ptr, val_ptr) -> f64 (undefined-tag)
diff --git a/crates/perry-runtime/src/array/flat_clone.rs b/crates/perry-runtime/src/array/flat_clone.rs
index c69be29769..2365a2c250 100644
--- a/crates/perry-runtime/src/array/flat_clone.rs
+++ b/crates/perry-runtime/src/array/flat_clone.rs
@@ -458,7 +458,7 @@ pub extern "C" fn js_array_clone(src: *const ArrayHeader) -> *mut ArrayHeader {
         let top16 = (src as u64) >> 48;
         if top16 == 0x7FFF {
             true
-        } else if raw_addr >= crate::gc::GC_HEADER_SIZE + 0x1000 {
+        } else if crate::value::addr_class::is_above_handle_band(raw_addr) {
             unsafe {
                 let hdr = (raw_addr as *const u8).sub(crate::gc::GC_HEADER_SIZE)
                     as *const crate::gc::GcHeader;
@@ -478,6 +478,15 @@ pub extern "C" fn js_array_clone(src: *const ArrayHeader) -> *mut ArrayHeader {
     // helper after codegen strips the tag, so ask the generic iterator resolver
     // before treating the id as a non-array and returning [].
     if crate::value::addr_class::is_small_handle(raw_addr) {
+        // #10270: a Proxy id has no GC/ArrayHeader. Only the existing handle
+        // arm probes the registry; plain arrays keep their classification and
+        // copy path. Array.from permits array-like proxies as well as iterables.
+        if let Some(proxy) = array_ptr_as_proxy(raw_addr as *const ArrayHeader) {
+            let undefined = f64::from_bits(crate::value::TAG_UNDEFINED);
+            let result =
+                super::from_concat::array_from_full(undefined, proxy, undefined, undefined);
+            return crate::value::js_nanbox_get_pointer(result) as *mut ArrayHeader;
+        }
         if let Some(dispatch) = crate::object::handle_property_dispatch() {
             let method = b"@@iterator";
             let iter_fn = unsafe { dispatch(raw_addr as i64, method.as_ptr(), method.len()) };
diff --git a/crates/perry-runtime/src/array/from_concat.rs b/crates/perry-runtime/src/array/from_concat.rs
index 0903c98cd0..a2c5ae57b7 100644
--- a/crates/perry-runtime/src/array/from_concat.rs
+++ b/crates/perry-runtime/src/array/from_concat.rs
@@ -12,6 +12,8 @@ use super::{
 use crate::closure::ClosureHeader;
 use crate::value::JSValue;
 
+mod proxy_from;
+
 const TAG_UNDEFINED: u64 = 0x7FFC_0000_0000_0001;
 const TAG_NULL: u64 = 0x7FFC_0000_0000_0002;
 
@@ -720,6 +722,13 @@ pub fn array_from_full(c: f64, items: f64, mapfn: f64, this_arg: f64) -> f64 {
         throw_not_iterable("object null");
     }
 
+    // Proxy GetMethod is observable. Resolve it once, retain it across
+    // construction, and root iterator state across callbacks that can collect.
+    if let Some(proxy) = crate::array::array_ptr_as_proxy(
+        crate::value::js_nanbox_get_pointer(items) as *const ArrayHeader,
+    ) {
+        return proxy_from::array_from_proxy(c, proxy, mapfn, this_arg, mapping);
+    }
     let is_ctor = is_constructor_value(c);
 
     if items_is_iterable(items) {
@@ -1037,8 +1046,10 @@ unsafe fn try_append_spread_array_dense(
     src: *const ArrayHeader,
 ) -> Option<*mut ArrayHeader> {
     // A masked proxy id is not a dereferenceable ArrayHeader.
-    if crate::array::array_ptr_as_proxy(src).is_some() {
-        return None;
+    if let Some(proxy) = crate::array::array_ptr_as_proxy(src) {
+        // Concat uses HasProperty/Get, never @@iterator. Resolve this inside
+        // the existing proxy guard so the ordinary bulk-copy path is unchanged.
+        return Some(append_concat_proxy(result, proxy));
     }
     let src = clean_arr_ptr(src);
     if src.is_null() {
@@ -1131,6 +1142,32 @@ unsafe fn try_append_spread_array_dense(
     Some(result)
 }
 
+/// Indexed concat of a proxy, preserving holes and observing its traps.
+unsafe fn append_concat_proxy(result: *mut ArrayHeader, proxy: f64) -> *mut ArrayHeader {
+    let scope = crate::gc::RuntimeHandleScope::new();
+    let result = scope.root_raw_mut_ptr(result);
+    let proxy = scope.root_nanbox_f64(proxy);
+    let (_, result) = result.across_mut(|| {
+        let len = array_like_length(proxy.get_nanbox_f64());
+        for index in 0..len {
+            let entry_scope = crate::gc::RuntimeHandleScope::new();
+            let name = index.to_string();
+            let key = crate::string::js_string_from_bytes(name.as_ptr(), name.len() as u32);
+            let key = entry_scope.root_nanbox_f64(crate::value::js_nanbox_string(key as i64));
+            let present =
+                crate::object::js_object_has_property(proxy.get_nanbox_f64(), key.get_nanbox_f64());
+            let value = if crate::value::js_is_truthy(present) != 0 {
+                crate::proxy::js_proxy_get(proxy.get_nanbox_f64(), key.get_nanbox_f64())
+            } else {
+                f64::from_bits(crate::value::TAG_HOLE)
+            };
+            let grown = result.with_mut_ptr(|ptr| js_array_push_f64(ptr, value));
+            result.set_raw_mut_ptr(grown);
+        }
+    });
+    result
+}
+
 /// Append every element of the (already-materializable) source array `src`
 /// into `result`, returning the (possibly reallocated) result. `src` is
 /// materialized via `js_array_clone` so sets/maps/typed-arrays/buffers spread
diff --git a/crates/perry-runtime/src/array/from_concat/proxy_from.rs b/crates/perry-runtime/src/array/from_concat/proxy_from.rs
new file mode 100644
index 0000000000..a65cfab5b3
--- /dev/null
+++ b/crates/perry-runtime/src/array/from_concat/proxy_from.rs
@@ -0,0 +1,181 @@
+//! Proxy-only Array.from: one GetMethod, with roots across user callbacks.
+use super::*;
+use crate::gc::{RuntimeHandle, RuntimeHandleScope};
+
+fn get(value: &RuntimeHandle<'_>, name: &[u8]) -> f64 {
+    let key = crate::string::js_string_from_bytes(name.as_ptr(), name.len() as u32);
+    let raw = crate::value::js_nanbox_get_pointer(value.get_nanbox_f64());
+    crate::object::js_object_get_field_by_name_f64(raw as *const crate::ObjectHeader, key)
+}
+
+fn invoke(method: &RuntimeHandle<'_>, receiver: &RuntimeHandle<'_>) -> Result<f64, f64> {
+    let scope = RuntimeHandleScope::new();
+    let rebound = crate::closure::clone_closure_rebind_this(
+        method.get_nanbox_f64().to_bits(),
+        receiver.get_nanbox_f64(),
+    );
+    let rebound = scope.root_nanbox_f64(f64::from_bits(rebound));
+    crate::collection_iter::call_with_this_capturing_throw(
+        rebound.get_nanbox_f64(),
+        receiver.get_nanbox_f64(),
+        &[],
+    )
+}
+
+fn define(result: &RuntimeHandle<'_>, index: usize, value: f64, fresh_array: bool) {
+    if fresh_array {
+        let raw = crate::value::js_nanbox_get_pointer(result.get_nanbox_f64());
+        let grown = js_array_set_f64_extend(raw as *mut ArrayHeader, index as u32, value);
+        result.set_nanbox_f64(crate::value::js_nanbox_pointer(grown as i64));
+        return;
+    }
+    let scope = RuntimeHandleScope::new();
+    let value = scope.root_nanbox_f64(value);
+    let desc = scope.root_raw_mut_ptr(crate::object::js_object_alloc(0, 4));
+    for name in [
+        b"value".as_slice(),
+        b"writable",
+        b"enumerable",
+        b"configurable",
+    ] {
+        let key = crate::string::js_string_from_bytes(name.as_ptr(), name.len() as u32);
+        let field = if name == b"value" {
+            value.get_nanbox_f64()
+        } else {
+            f64::from_bits(TAG_TRUE)
+        };
+        desc.with_mut_ptr(|ptr| crate::object::js_object_set_field_by_name(ptr, key, field));
+    }
+    let name = index.to_string();
+    let key = crate::string::js_string_from_bytes(name.as_ptr(), name.len() as u32);
+    let key = scope.root_nanbox_f64(crate::value::js_nanbox_string(key as i64));
+    let descriptor = desc.with_const_ptr::<crate::ObjectHeader, _>(|ptr| {
+        crate::value::js_nanbox_pointer(ptr as i64)
+    });
+    if crate::proxy::js_reflect_define_property(
+        result.get_nanbox_f64(),
+        key.get_nanbox_f64(),
+        descriptor,
+    )
+    .to_bits()
+        != TAG_TRUE
+    {
+        throw_cannot_define_property(index);
+    }
+}
+
+fn finish(result: &RuntimeHandle<'_>, len: usize, fresh_array: bool) -> f64 {
+    if fresh_array {
+        let raw = crate::value::js_nanbox_get_pointer(result.get_nanbox_f64());
+        crate::array::js_array_set_length(raw as *mut ArrayHeader, len as f64);
+    } else {
+        let key = crate::string::js_string_from_bytes(b"length".as_ptr(), 6);
+        let key = crate::value::js_nanbox_string(key as i64);
+        let current = result.get_nanbox_f64();
+        crate::proxy::js_put_value_set(current, key, len as f64, current, 1);
+    }
+    result.get_nanbox_f64()
+}
+
+pub(super) fn array_from_proxy(
+    c: f64,
+    items: f64,
+    mapfn: f64,
+    this_arg: f64,
+    mapping: bool,
+) -> f64 {
+    let scope = RuntimeHandleScope::new();
+    let constructor = scope.root_nanbox_f64(c);
+    let items = scope.root_nanbox_f64(items);
+    let mapfn = scope.root_nanbox_f64(mapfn);
+    let this_arg = scope.root_nanbox_f64(this_arg);
+    let symbol = crate::symbol::well_known_symbol("iterator");
+    let method = unsafe {
+        crate::symbol::js_object_get_symbol_property(
+            items.get_nanbox_f64(),
+            crate::value::js_nanbox_pointer(symbol as i64),
+        )
+    };
+    let method = scope.root_nanbox_f64(method);
+    let iterable = !matches!(method.get_nanbox_f64().to_bits(), TAG_UNDEFINED | TAG_NULL);
+    if iterable {
+        resolve_callable(method.get_nanbox_f64());
+    }
+    let fresh_array = !is_constructor_value(constructor.get_nanbox_f64());
+    let len = if iterable {
+        0
+    } else {
+        array_like_length(items.get_nanbox_f64())
+    };
+    let result = if fresh_array {
+        crate::value::js_nanbox_pointer(js_array_alloc(0) as i64)
+    } else {
+        let args = [len as f64];
+        unsafe {
+            crate::object::js_new_function_construct(
+                constructor.get_nanbox_f64(),
+                args.as_ptr(),
+                if iterable { 0 } else { 1 },
+            )
+        }
+    };
+    let result = scope.root_nanbox_f64(result);
+    if !iterable {
+        for index in 0..len {
+            let value = crate::object::js_object_get_index_polymorphic(
+                items.get_nanbox_f64().to_bits() as i64,
+                index as f64,
+            );
+            let value = if mapping {
+                call_map_fn(
+                    mapfn.get_nanbox_f64(),
+                    this_arg.get_nanbox_f64(),
+                    value,
+                    index,
+                )
+            } else {
+                value
+            };
+            define(&result, index, value, fresh_array);
+        }
+        return finish(&result, len, fresh_array);
+    }
+    // GetIteratorFromMethod uses the saved method even if construction mutates
+    // @@iterator. The iterator record likewise reads its next method only once.
+    let iter = invoke(&method, &items).unwrap_or_else(|error| crate::exception::js_throw(error));
+    crate::symbol::js_iterator_result_validate(iter);
+    let iter = scope.root_nanbox_f64(iter);
+    let next = scope.root_nanbox_f64(get(&iter, b"next"));
+    let mut index = 0;
+    loop {
+        let step_scope = RuntimeHandleScope::new();
+        let step = invoke(&next, &iter).unwrap_or_else(|error| crate::exception::js_throw(error));
+        crate::symbol::js_iterator_result_validate(step);
+        let step = step_scope.root_nanbox_f64(step);
+        if crate::value::js_is_truthy(get(&step, b"done")) != 0 {
+            break;
+        }
+        let value = step_scope.root_nanbox_f64(get(&step, b"value"));
+        let completion = crate::collection_iter::call_capturing_throw(|| {
+            let mapped = if mapping {
+                call_map_fn(
+                    mapfn.get_nanbox_f64(),
+                    this_arg.get_nanbox_f64(),
+                    value.get_nanbox_f64(),
+                    index,
+                )
+            } else {
+                value.get_nanbox_f64()
+            };
+            define(&result, index, mapped, fresh_array);
+            f64::from_bits(TAG_UNDEFINED)
+        });
+        if let Err(error) = completion {
+            let error = step_scope.root_nanbox_f64(error);
+            crate::collection_iter::iterator_close(iter.get_nanbox_f64());
+            crate::exception::js_throw(error.get_nanbox_f64());
+        }
+        index += 1;
+    }
+    finish(&result, index, fresh_array)
+}
diff --git a/crates/perry-runtime/src/array/iterator.rs b/crates/perry-runtime/src/array/iterator.rs
index bc277d6b8d..79ed386779 100644
--- a/crates/perry-runtime/src/array/iterator.rs
+++ b/crates/perry-runtime/src/array/iterator.rs
@@ -102,6 +102,13 @@ pub extern "C" fn js_for_of_to_array(val_f64: f64) -> f64 {
         throw_not_iterable(val_f64);
     }
 
+    // Proxy ids are not heap headers. Use the same trapped iterator as spread.
+    if let Some(proxy) = array_ptr_as_proxy(raw_ptr as *const ArrayHeader) {
+        return js_nanbox_pointer(
+            js_iterator_to_array(crate::symbol::js_get_iterator(proxy)) as i64
+        );
+    }
+
     // Inspect the GC header's object kind to dispatch Array / Map / Set
     // without consulting any static type.
     let obj_type = unsafe {
diff --git a/crates/perry-runtime/src/collection_iter.rs b/crates/perry-runtime/src/collection_iter.rs
index 44d5c801b4..1e64d79e15 100644
--- a/crates/perry-runtime/src/collection_iter.rs
+++ b/crates/perry-runtime/src/collection_iter.rs
@@ -254,6 +254,13 @@ pub(crate) fn constructor_iter(value: f64) -> ConstructorIter {
     let jsv = JSValue::from_bits(value.to_bits());
     let is_array = crate::array::js_array_is_array(value).to_bits() == crate::value::TAG_TRUE;
     if is_array {
+        if crate::array::array_ptr_as_proxy(
+            js_nanbox_get_pointer(value) as *const crate::array::ArrayHeader
+        )
+        .is_some()
+        {
+            return ConstructorIter::Iterator(crate::symbol::js_get_iterator(value));
+        }
         return ConstructorIter::Array(value);
     }
     if jsv.is_any_string() {
diff --git a/crates/perry-runtime/src/object/arguments.rs b/crates/perry-runtime/src/object/arguments.rs
index cf1ad044f6..41cf23d17f 100644
--- a/crates/perry-runtime/src/object/arguments.rs
+++ b/crates/perry-runtime/src/object/arguments.rs
@@ -717,7 +717,9 @@ pub extern "C" fn js_array_like_to_array(value: f64) -> *mut ArrayHeader {
         // sticky flag that is false until user code writes the prototype slot,
         // so the fast path is untouched in every ordinary program.
         if crate::array::js_array_is_array(value).to_bits() == crate::value::TAG_TRUE {
-            if crate::array::array_proto_iterator_modified() {
+            if crate::array::array_proto_iterator_modified()
+                || crate::array::array_ptr_as_proxy(raw as *const ArrayHeader).is_some()
+            {
                 return crate::array::js_array_clone_for_spread(value);
             }
             return crate::array::clean_arr_ptr(raw as *const ArrayHeader) as *mut ArrayHeader;
diff --git a/crates/perry-runtime/src/object/polymorphic_index.rs b/crates/perry-runtime/src/object/polymorphic_index.rs
index 0468240fe0..bbb7daa4aa 100644
--- a/crates/perry-runtime/src/object/polymorphic_index.rs
+++ b/crates/perry-runtime/src/object/polymorphic_index.rs
@@ -174,7 +174,15 @@ pub extern "C" fn js_object_get_index_polymorphic(obj_handle: i64, idx: f64) ->
     } else {
         obj_handle as u64
     };
-    if raw < 0x1000 {
+    // Array.from's array-like fallback can receive a Proxy record. Its id is
+    // not a heap header; route it inside the existing low-address guard so
+    // ordinary heap receivers do not perform a proxy registry lookup.
+    if crate::value::addr_class::is_handle_band(raw as usize) {
+        if let Some(proxy) =
+            crate::array::array_ptr_as_proxy(raw as *const crate::array::ArrayHeader)
+        {
+            return crate::proxy::js_proxy_get(proxy, idx);
+        }
         return f64::from_bits(crate::value::TAG_UNDEFINED);
     }
     // Symbols share GC_TYPE_STRING storage for tracing, but they are primitive
diff --git a/crates/perry-runtime/src/stdlib_stubs.rs b/crates/perry-runtime/src/stdlib_stubs.rs
index dd9fa2fa3e..7779a1ab34 100644
--- a/crates/perry-runtime/src/stdlib_stubs.rs
+++ b/crates/perry-runtime/src/stdlib_stubs.rs
@@ -192,6 +192,13 @@ pub extern "C" fn js_headers_new() -> f64 {
     f64::from_bits(crate::value::TAG_UNDEFINED)
 }
 
+#[cfg(not(feature = "external-fetch-symbols"))]
+#[no_mangle]
+pub extern "C" fn js_headers_from_value(_init: f64) -> f64 {
+    perry_stub_warn("js_headers_from_value", FETCH_REASON, None);
+    f64::from_bits(crate::value::TAG_UNDEFINED)
+}
+
 #[cfg(not(feature = "external-fetch-symbols"))]
 #[no_mangle]
 pub extern "C" fn js_headers_init_from_value(_handle: f64, _init: f64) -> f64 {
diff --git a/crates/perry-runtime/src/symbol/get.rs b/crates/perry-runtime/src/symbol/get.rs
index 326f73dee6..ed72157767 100644
--- a/crates/perry-runtime/src/symbol/get.rs
+++ b/crates/perry-runtime/src/symbol/get.rs
@@ -1141,22 +1141,19 @@ pub unsafe extern "C" fn js_object_get_symbol_property(obj_f64: f64, sym_f64: f6
             }
         }
     }
-    // #321: arrays expose `Symbol.iterator`. perry has no standalone array
-    // iterator object (for-of is special-cased), but `arr[Symbol.iterator]`
-    // must resolve to a callable so `Symbol.iterator in arr` is true
-    // (effect's `Predicate.isIterable`) and `typeof arr[Symbol.iterator]` is
-    // "function". Bind the array's `values` method as that callable. Pre-fix
-    // the symbol key fell through to the numeric/string paths and read back a
-    // number, so `isIterable([...])` was false and `Effect.all`'s
-    // predicate-`dual` `forEach` went data-last (returned a function).
+    // Return the actual prototype iterator, whose thunk reads call-time this.
+    // Binding `values` to this array makes a Proxy get trap returning
+    // target[Symbol.iterator] iterate the target, bypassing length/index traps
+    // even when GetIterator calls the method with the Proxy receiver (#10270).
     if crate::array::js_array_is_array(obj_f64).to_bits() == crate::value::TAG_TRUE {
         let iter_wk = well_known_symbol("iterator");
         if !iter_wk.is_null() {
             let iter_f64 =
                 f64::from_bits(crate::value::JSValue::pointer(iter_wk as *const u8).bits());
             if sym_key_from_f64(sym_f64) == sym_key_from_f64(iter_f64) {
-                let mname = b"values";
-                return crate::object::js_class_method_bind(obj_f64, mname.as_ptr(), mname.len());
+                let proto = crate::object::builtin_prototype_value("Array");
+                return own_symbol_property(proto, sym_f64)
+                    .unwrap_or(f64::from_bits(crate::value::TAG_UNDEFINED));
             }
         }
     }
diff --git a/crates/perry-stdlib/src/fetch/headers.rs b/crates/perry-stdlib/src/fetch/headers.rs
index eab946c46c..1192b2dcc4 100644
--- a/crates/perry-stdlib/src/fetch/headers.rs
+++ b/crates/perry-stdlib/src/fetch/headers.rs
@@ -21,6 +21,31 @@ pub extern "C" fn js_headers_new() -> f64 {
     handle_to_f64(alloc_headers(HeadersStore::default()))
 }
 
+/// Normalize a runtime `HeadersInit` value to a Headers handle.
+///
+/// A genuine Headers handle is already in the representation consumed by the
+/// Request constructor, which clones its entries into the Request record. Keep
+/// that handle instead of allocating and filling a redundant intermediate
+/// store. Records, iterables, and Proxies still take the full constructor path.
+#[no_mangle]
+pub extern "C" fn js_headers_from_value(init: f64) -> f64 {
+    let scope = perry_runtime::gc::RuntimeHandleScope::new();
+    let init = scope.root_nanbox_f64(init);
+    let current = init.get_nanbox_f64();
+    if perry_runtime::proxy::js_proxy_is_proxy(current) == 0 {
+        let id = handle_id(current);
+        if HEADERS_REGISTRY.lock().unwrap().contains_key(&id) {
+            return current;
+        }
+    }
+
+    let handle = js_headers_new();
+    unsafe {
+        js_headers_init_from_value(handle, init.get_nanbox_f64());
+    }
+    handle
+}
+
 unsafe fn header_init_string(value: f64) -> String {
     let ptr = perry_runtime::value::js_jsvalue_to_string(value);
     string_from_header(ptr as *const StringHeader).unwrap_or_default()
@@ -293,7 +318,13 @@ unsafe fn materialize_header_pair(
     if !is_headers_init_iterable(pair_value) {
         headers_init_type_error("Headers constructor: expected name/value pair");
     }
-    let pair_array_value = if perry_runtime::js_array_is_array(pair_value).to_bits() == TAG_TRUE {
+    // IsArray also accepts proxy ids and object-backed Array subclasses; only
+    // a real array header may bypass iterable materialization (#10270).
+    let raw = perry_runtime::js_nanbox_get_pointer(pair_value);
+    let pair_array_value = if matches!(
+        gc_type_for_raw_ptr(raw),
+        Some(perry_runtime::gc::GC_TYPE_ARRAY | perry_runtime::gc::GC_TYPE_LAZY_ARRAY)
+    ) {
         pair_value
     } else {
         perry_runtime::array::js_for_of_to_array(pair_value)
diff --git a/crates/perry/src/commands/compile/run_pipeline.rs b/crates/perry/src/commands/compile/run_pipeline.rs
index f751ace6dc..e25bd6ea3f 100644
--- a/crates/perry/src/commands/compile/run_pipeline.rs
+++ b/crates/perry/src/commands/compile/run_pipeline.rs
@@ -3319,8 +3319,29 @@ pub fn run_with_parse_cache(
                 .enumerate()
                 .map(|(i, name)| (sanitize_name(name), i))
                 .collect();
+            //
+            // A Deferred dep is the exception (#10278). The back-edge drop is
+            // sound only because the entry's eager init loop runs every Eager
+            // module in `init_pos` order, so a dep positioned before this
+            // module has already initialized by the time this wrapper runs.
+            // Deferred modules are filtered OUT of that loop — nothing runs
+            // them but a dynamic-import dispatch site or another wrapper — so
+            // dropping the edge to one strands it: its body never runs and
+            // every export the body assigns at runtime stays undefined. A
+            // static `import()` entry into a Deferred cycle reproduced it
+            // (`useAssigned()` returned undefined, `obj.method` threw). Keep
+            // the edge whenever the dep is Deferred; the `__init` guard
+            // already makes the call idempotent and cycle-safe, and it
+            // reproduces ESM's order (the partner body runs first, the
+            // re-entrant call returns immediately). This cannot perturb the
+            // Eager ordering #6463 fixed: a module statically imported by an
+            // Eager module is itself statically reachable from the entry, so
+            // it is Eager, so this arm never fires for it.
             if let Some(&self_pos) = init_pos.get(&sanitize_name(&hir_module.name)) {
-                deps.retain(|dep| init_pos.get(dep).map_or(true, |&p| p < self_pos));
+                deps.retain(|dep| {
+                    deferred_module_prefixes.contains(dep)
+                        || init_pos.get(dep).map_or(true, |&p| p < self_pos)
+                });
             }
             deps
         };
diff --git a/crates/perry/src/commands/compile/strip_dedup/stub_symbols.rs b/crates/perry/src/commands/compile/strip_dedup/stub_symbols.rs
index 35b22442f6..762f0d5376 100644
--- a/crates/perry/src/commands/compile/strip_dedup/stub_symbols.rs
+++ b/crates/perry/src/commands/compile/strip_dedup/stub_symbols.rs
@@ -23,6 +23,7 @@ const STDLIB_STUB_SYMBOLS: &[&str] = &[
     "js_fetch_with_options",
     "js_blob_new",
     "js_headers_new",
+    "js_headers_from_value",
     "js_headers_init_from_value",
     "js_request_new",
     "js_response_new",
diff --git a/crates/perry/tests/issue_10270_proxy_array_from.rs b/crates/perry/tests/issue_10270_proxy_array_from.rs
new file mode 100644
index 0000000000..25de2c03da
--- /dev/null
+++ b/crates/perry/tests/issue_10270_proxy_array_from.rs
@@ -0,0 +1,88 @@
+//! #10270: IsArray is not proof that a Proxy id is an ArrayHeader.
+
+mod support;
+
+const SOURCE: &str = r#"
+const t = (name: string, f: () => any) => { try { console.log(name, JSON.stringify(f())) } catch (e: any) { console.log(name, "THROW", e.message) } }
+const pa = () => new Proxy([["x-a", "1"]], {})
+t("Q1 [...proxyOverArray]", () => [...(pa() as any)].length)
+t("Q2 for..of proxyOverArray", () => { let n = 0; for (const _ of pa() as any) n++; return n })
+t("Q3 Array.isArray(proxyOverArray)", () => Array.isArray(pa()))
+t("Q4 proxy[Symbol.iterator] typeof", () => typeof (pa() as any)[Symbol.iterator])
+t("Q5 Array.from(proxyOverArray)", () => Array.from(pa() as any).length)
+t("nested", () => Array.from(new Proxy(new Proxy([1, 2], {}), {})))
+t("trapped indices", () => Array.from(new Proxy([1, 2], { get(t: any, k: any) { return k === "0" ? 9 : t[k]; } })))
+t("custom iterator", () => Array.from(new Proxy([1, 2], { get(t: any, k: any) { return k === Symbol.iterator ? () => [7, 8, 9].values() : t[k]; } })))
+t("mapped", () => Array.from(new Proxy([1, 2], {}), (v: number, i: number) => v + i))
+t("mapped custom iterator", () => Array.from(new Proxy([1, 2], { get(t: any, k: any) { return k === Symbol.iterator ? () => [7, 8, 9].values() : t[k]; } }), (v: number) => v * 2))
+t("arraylike", () => Array.from(new Proxy({ 0: "a", 1: "b", length: 2 }, {})))
+t("removed iterator", () => Array.from(new Proxy([1, 2], { get(t: any, k: any) { return k === Symbol.iterator ? undefined : t[k]; } })))
+t("record iterator", () => Array.from(new Proxy({}, { get(t: any, k: any) { return k === Symbol.iterator ? () => [5, 6].values() : t[k]; } })))
+t("headers outer", () => new Headers(new Proxy([["x-a", "1"]], {}) as any).get("x-a"))
+t("headers pair", () => new Headers([new Proxy(["x-a", "1"], {})] as any).get("x-a"))
+t("plain array", () => Array.from([3, 4]))
+t("of preserves proxy", () => { const p = new Proxy([1, 2], {}); return Array.of(p)[0] === p; })
+t("concat indices", () => [0].concat(new Proxy([1, 2], { get(t: any, k: any) { return k === Symbol.iterator ? () => [9].values() : k === "0" ? 7 : t[k]; } })))
+t("concat holes", () => { const a = [0].concat(new Proxy([, 2], {})); return [a.length, 1 in a, a[2]]; })
+t("call spread", () => { const count = (...xs: any[]) => xs.length; return count(...new Proxy([1, 2], {})); })
+t("set iterator", () => Array.from(new Set(new Proxy([1, 2], { get(t: any, k: any) { return k === Symbol.iterator ? () => [7, 8].values() : t[k]; } }))))
+Promise.all(new Proxy([Promise.resolve(1), Promise.resolve(2)], {})).then(v => console.log("all", JSON.stringify(v)))
+"#;
+
+#[test]
+fn proxy_array_from_and_headers_iterables() {
+    assert_eq!(
+        support::compile_and_run(SOURCE),
+        concat!(
+            "Q1 [...proxyOverArray] 1\n",
+            "Q2 for..of proxyOverArray 1\n",
+            "Q3 Array.isArray(proxyOverArray) true\n",
+            "Q4 proxy[Symbol.iterator] typeof \"function\"\n",
+            "Q5 Array.from(proxyOverArray) 1\n",
+            "nested [1,2]\n",
+            "trapped indices [9,2]\n",
+            "custom iterator [7,8,9]\n",
+            "mapped [1,3]\n",
+            "mapped custom iterator [14,16,18]\n",
+            "arraylike [\"a\",\"b\"]\n",
+            "removed iterator [1,2]\n",
+            "record iterator [5,6]\n",
+            "headers outer \"1\"\n",
+            "headers pair \"1\"\n",
+            "plain array [3,4]\n",
+            "of preserves proxy true\n",
+            "concat indices [0,7,2]\n",
+            "concat holes [3,false,2]\n",
+            "call spread 2\n",
+            "set iterator [7,8]\n",
+            "all [1,2]\n",
+        )
+    );
+}
+
+#[test]
+fn proxy_array_from_reads_iterator_methods_once_and_closes_on_mapping_throw() {
+    let source = r#"
+let reads = 0;
+const p = new Proxy([1, 2], { get(t: any, k: any) {
+  if (k === Symbol.iterator) { reads++; return reads === 1 ? function() { return [4, 5].values(); } : undefined; }
+  return t[k];
+}});
+console.log("method", JSON.stringify(Array.from(p)), reads);
+let nextReads = 0, steps = 0, closed = 0;
+const it = { get next() { nextReads++; return function() { return steps++ < 2 ? {done:false, value:7} : {done:true}; }; }, return() { closed++; return {done:true}; } };
+const q = new Proxy({}, {get(t:any,k:any) { return k === Symbol.iterator ? () => it : undefined; }});
+console.log("next", JSON.stringify(Array.from(q)), nextReads);
+steps = 0;
+try { Array.from(q, () => { throw new Error("mapped"); }); } catch(e:any) { console.log("close",e.message,closed); }
+let selected = false;
+const r = new Proxy([1], {get(t:any,k:any) { if(k === Symbol.iterator) { selected = true; return function() { return [8].values(); }; } return t[k]; }});
+function C() { console.log("constructor", selected); }
+const result:any = Array.from.call(C, r);
+console.log("constructed", result[0], result.length);
+"#;
+    assert_eq!(
+        support::compile_and_run(source),
+        "method [4,5] 1\nnext [7,7] 1\nclose mapped 1\nconstructor true\nconstructed 8 1\n"
+    );
+}
diff --git a/crates/perry/tests/issue_10274_request_proxy_headers.rs b/crates/perry/tests/issue_10274_request_proxy_headers.rs
new file mode 100644
index 0000000000..de3c09438d
--- /dev/null
+++ b/crates/perry/tests/issue_10274_request_proxy_headers.rs
@@ -0,0 +1,51 @@
+//! #10274: a dynamic HeadersInit in a literal RequestInit needs conversion.
+
+mod support;
+
+const SOURCE: &str = r#"
+const dump = (h: any) => { const out: string[] = []; h.forEach((v: string, k: string) => out.push(k + "=" + v)); return out.sort() }
+const proxy = new Proxy({ "x-a": "1" }, {})
+console.log("direct", JSON.stringify(dump(new Headers(proxy as any))))
+console.log("request", JSON.stringify(dump(new Request("https://x.dev", { headers: proxy as any }).headers)))
+function make(headers: any) { return new Request("https://x.dev", { headers }).headers; }
+function init(headers: any): any { return { headers }; }
+console.log("parameter", JSON.stringify(dump(make(proxy))))
+console.log("runtime init", JSON.stringify(dump(new Request("https://x.dev", init(proxy)).headers)))
+const trapped = new Proxy({ "authorization": "secret", "x-hidden": "hidden" }, {
+  ownKeys() { return ["authorization"]; },
+  get(t: any, k: any) { return k === "authorization" ? "Bearer token" : t[k]; }
+});
+console.log("traps", JSON.stringify(dump(make(trapped))))
+console.log("record", JSON.stringify(dump(make({ "x-a": "1" }))))
+console.log("pairs", JSON.stringify(dump(make([["x-a", "1"], ["x-a", "2"]]))))
+console.log("handle", JSON.stringify(dump(make(new Headers({ "x-a": "1" })))))
+console.log("literal", JSON.stringify(dump(new Request("https://x.dev", { headers: { "x-a": "1" } }).headers)))
+const source = new Headers({ "x-a": "1" })
+const copied = make(source)
+source.set("x-b", "2")
+copied.set("x-c", "3")
+console.log("independent", JSON.stringify(dump(source)), JSON.stringify(dump(copied)), copied !== source)
+console.log("absent", JSON.stringify(dump(make(undefined))))
+try { make(null); console.log("null accepted") } catch (e) { console.log("null", e instanceof TypeError) }
+"#;
+
+#[test]
+fn request_converts_dynamic_headers_init() {
+    assert_eq!(
+        support::compile_and_run(SOURCE),
+        concat!(
+            "direct [\"x-a=1\"]\n",
+            "request [\"x-a=1\"]\n",
+            "parameter [\"x-a=1\"]\n",
+            "runtime init [\"x-a=1\"]\n",
+            "traps [\"authorization=Bearer token\"]\n",
+            "record [\"x-a=1\"]\n",
+            "pairs [\"x-a=1, 2\"]\n",
+            "handle [\"x-a=1\"]\n",
+            "literal [\"x-a=1\"]\n",
+            "independent [\"x-a=1\",\"x-b=2\"] [\"x-a=1\",\"x-c=3\"] true\n",
+            "absent []\n",
+            "null true\n",
+        )
+    );
+}
diff --git a/crates/perry/tests/issue_10278_dynamic_import_cycle_init.rs b/crates/perry/tests/issue_10278_dynamic_import_cycle_init.rs
new file mode 100644
index 0000000000..f56e39ed8e
--- /dev/null
+++ b/crates/perry/tests/issue_10278_dynamic_import_cycle_init.rs
@@ -0,0 +1,145 @@
+//! Regression test for #10278: a module reached only through a dynamic
+//! `import()` (`ModuleInitKind::Deferred`) that takes part in an import cycle
+//! must still initialize its cycle partner.
+//!
+//! `module_init_deps` (run_pipeline) drops init-call back-edges so that an
+//! Eager module's `__init` wrapper never re-enters a cycle member the entry's
+//! eager init loop has already run — that is #6463, and dropping the edge is
+//! only sound *because* that loop exists. Deferred modules are filtered out of
+//! it (`codegen/entry.rs`), so nothing else runs them: dropping a wrapper's
+//! edge to a Deferred dep strands the dep forever. Its body never runs and
+//! every export the body assigns at runtime stays undefined, which surfaces as
+//! `TypeError: value is not a function` on the first call through such a slot.
+//!
+//! The two tests are deliberately a pair. `dynamic` is the defect: it fails on
+//! the pre-fix compiler with `assigned-UNDEFINED`. `static_control` pins the
+//! #6463 ordering it must not disturb — the same cycle entered statically,
+//! where the eager loop is what initializes both members.
+
+use std::path::PathBuf;
+use std::process::Command;
+
+fn perry_bin() -> PathBuf {
+    PathBuf::from(env!("CARGO_BIN_EXE_perry"))
+}
+
+fn runtime_dir() -> PathBuf {
+    std::env::var_os("PERRY_RUNTIME_DIR")
+        .map(PathBuf::from)
+        .unwrap_or_else(|| {
+            perry_bin()
+                .parent()
+                .expect("compiler directory")
+                .to_path_buf()
+        })
+}
+
+/// Cycle member whose body assigns two exports at run time. A function
+/// declaration alone would not witness the bug: those are reachable without the
+/// body ever running.
+const CYCLE_A: &str = "\
+console.log(\"[init] a body start\");
+import { bFn } from \"./b.js\";
+export let assigned;
+assigned = () => \"a-assigned-ok\";
+export const obj = {};
+obj.method = () => \"a-obj-method-ok\";
+export function aFn() { return \"a:\" + bFn(); }
+console.log(\"[init] a body end\");
+";
+
+const CYCLE_B: &str = "\
+console.log(\"[init] b body start\");
+import { aFn, assigned, obj } from \"./a.js\";
+export function bFn() { return \"b\"; }
+export function useA() { return aFn(); }
+export function useAssigned() { return assigned ? assigned() : \"assigned-UNDEFINED\"; }
+export function useObj() {
+  return typeof obj.method === \"function\" ? obj.method() : \"obj-method-NOT-A-FUNCTION\";
+}
+console.log(\"[init] b body end\");
+";
+
+const DYNAMIC_ENTRY: &str = "\
+const m = await import(\"./b.js\");
+console.log(m.bFn(), m.useA(), m.useAssigned(), m.useObj());
+";
+
+const STATIC_ENTRY: &str = "\
+import { bFn, useA, useAssigned, useObj } from \"./b.js\";
+console.log(bFn(), useA(), useAssigned(), useObj());
+";
+
+/// Node and bun print the cycle partner's body first in both entry shapes.
+const EXPECTED: &str = "\
+[init] a body start
+[init] a body end
+[init] b body start
+[init] b body end
+b a:b a-assigned-ok a-obj-method-ok
+";
+
+fn compile_and_run(entry_src: &str) -> String {
+    let dir = tempfile::tempdir().expect("tempdir");
+    let root = dir.path();
+    std::fs::write(root.join("a.js"), CYCLE_A).unwrap();
+    std::fs::write(root.join("b.js"), CYCLE_B).unwrap();
+    std::fs::write(root.join("entry.js"), entry_src).unwrap();
+
+    let entry = root.join("entry.js");
+    let output = root.join("entry_bin");
+    let out = Command::new(perry_bin())
+        .current_dir(root)
+        .arg("compile")
+        .arg(&entry)
+        .arg("-o")
+        .arg(&output)
+        .arg("--no-cache")
+        .arg("--no-codegen")
+        .env("PERRY_NO_AUTO_OPTIMIZE", "1")
+        .env("PERRY_RUNTIME_DIR", runtime_dir())
+        .output()
+        .expect("run perry compile");
+    assert!(
+        out.status.success(),
+        "import cycle must compile; stdout:\n{}\nstderr:\n{}",
+        String::from_utf8_lossy(&out.stdout),
+        String::from_utf8_lossy(&out.stderr)
+    );
+
+    let run = Command::new(&output).output().expect("run compiled binary");
+    assert!(
+        run.status.success(),
+        "compiled cycle binary must run; stdout:\n{}\nstderr:\n{}",
+        String::from_utf8_lossy(&run.stdout),
+        String::from_utf8_lossy(&run.stderr)
+    );
+    String::from_utf8(run.stdout).expect("UTF-8 stdout")
+}
+
+#[test]
+fn dynamic_import_into_cycle_initializes_the_partner() {
+    let stdout = compile_and_run(DYNAMIC_ENTRY);
+    assert!(
+        stdout.contains("[init] a body start"),
+        "the cycle partner's body must run when the cycle is entered through \
+         a dynamic import; stdout:\n{stdout}"
+    );
+    assert!(
+        !stdout.contains("assigned-UNDEFINED") && !stdout.contains("obj-method-NOT-A-FUNCTION"),
+        "run-time-assigned exports of the cycle partner must be live; stdout:\n{stdout}"
+    );
+    assert_eq!(
+        stdout, EXPECTED,
+        "dynamic-import cycle output must match node/bun byte-for-byte"
+    );
+}
+
+#[test]
+fn static_import_into_cycle_keeps_the_6463_order() {
+    let stdout = compile_and_run(STATIC_ENTRY);
+    assert_eq!(
+        stdout, EXPECTED,
+        "static-import cycle output must match node/bun byte-for-byte"
+    );
+}
diff --git a/crates/perry/tests/support/mod.rs b/crates/perry/tests/support/mod.rs
new file mode 100644
index 0000000000..b3bdd36e36
--- /dev/null
+++ b/crates/perry/tests/support/mod.rs
@@ -0,0 +1,2 @@
+mod proxy_value_probe;
+pub use proxy_value_probe::compile_and_run;
diff --git a/crates/perry/tests/support/proxy_value_probe.rs b/crates/perry/tests/support/proxy_value_probe.rs
new file mode 100644
index 0000000000..c3d913c277
--- /dev/null
+++ b/crates/perry/tests/support/proxy_value_probe.rs
@@ -0,0 +1,44 @@
+use std::path::PathBuf;
+use std::process::Command;
+
+pub fn compile_and_run(source: &str) -> String {
+    let compiler = PathBuf::from(env!("CARGO_BIN_EXE_perry"));
+    let runtime = std::env::var_os("PERRY_RUNTIME_DIR")
+        .map(PathBuf::from)
+        .unwrap_or_else(|| compiler.parent().expect("compiler directory").to_path_buf());
+    let dir = tempfile::tempdir().expect("tempdir");
+    let entry = dir.path().join("main.ts");
+    let output = dir.path().join("main_bin");
+    std::fs::write(&entry, source).expect("write entry");
+    let compile = Command::new(compiler)
+        .current_dir(dir.path())
+        .arg("compile")
+        .arg(&entry)
+        .arg("-o")
+        .arg(&output)
+        .arg("--no-cache")
+        .arg("--no-codegen")
+        .env("PERRY_NO_AUTO_OPTIMIZE", "1")
+        .env("PERRY_RUNTIME_DIR", runtime)
+        .output()
+        .expect("compile probe");
+    assert!(
+        compile.status.success(),
+        "compile failed: {:?}\n{}\n{}",
+        compile.status,
+        String::from_utf8_lossy(&compile.stdout),
+        String::from_utf8_lossy(&compile.stderr)
+    );
+    let run = Command::new(output)
+        .current_dir(dir.path())
+        .output()
+        .expect("run compiled probe");
+    assert!(
+        run.status.success(),
+        "probe failed: {:?}\n{}\n{}",
+        run.status,
+        String::from_utf8_lossy(&run.stdout),
+        String::from_utf8_lossy(&run.stderr)
+    );
+    String::from_utf8(run.stdout).expect("UTF-8 output")
+}
diff --git a/scripts/addr_class_ratchet_baseline.txt b/scripts/addr_class_ratchet_baseline.txt
index 0562872ae5..32642c62a4 100644
--- a/scripts/addr_class_ratchet_baseline.txt
+++ b/scripts/addr_class_ratchet_baseline.txt
@@ -29,7 +29,7 @@ handle-floor | crates/perry-ext-http/src/agent.rs | 3
 handle-floor | crates/perry-ext-http/src/lib.rs | 2
 handle-floor | crates/perry-runtime/src/array/alloc.rs | 2
 handle-floor | crates/perry-runtime/src/array/concat_reverse.rs | 1
-handle-floor | crates/perry-runtime/src/array/flat_clone.rs | 4
+handle-floor | crates/perry-runtime/src/array/flat_clone.rs | 3
 handle-floor | crates/perry-runtime/src/array/generic.rs | 4
 handle-floor | crates/perry-runtime/src/array/header.rs | 3
 handle-floor | crates/perry-runtime/src/array/indexing.rs | 2