diff --git a/moli-renderer-v8/src/context_bootstrap/constructors/text_codecs.rs b/moli-renderer-v8/src/context_bootstrap/constructors/text_codecs.rs
index 68eb022a0c..0de07f7d80 100644
--- a/moli-renderer-v8/src/context_bootstrap/constructors/text_codecs.rs
+++ b/moli-renderer-v8/src/context_bootstrap/constructors/text_codecs.rs
@@ -124,9 +124,9 @@ struct TextDecoderOptions {
 
 #[derive(webidl::WebIdlArgs)]
 #[webidl(prefix = "TextDecoder.decode")]
-struct TextDecoderDecodeArgs {
-    #[webidl(converter = "buffer_source")]
-    input: Option<webidl::BufferSource>,
+struct TextDecoderDecodeArgs<'s> {
+    #[webidl(converter = "raw")]
+    input: Option<webidl::AllowSharedBufferSource<'s>>,
     #[webidl(index = 1, dictionary)]
     options: TextDecodeOptions,
 }
@@ -327,7 +327,7 @@ fn text_decoder_decode_callback<'s>(
     args: v8::FunctionCallbackArguments<'s>,
     mut rv: v8::ReturnValue<'s, v8::Value>,
 ) {
-    let Some(parsed) = webidl::parse_args::<TextDecoderDecodeArgs>(scope, &args) else {
+    let Some(parsed) = webidl::parse_args::<TextDecoderDecodeArgs<'s>>(scope, &args) else {
         rv.set_undefined();
         return;
     };
@@ -339,7 +339,7 @@ fn text_decoder_decode_callback<'s>(
     let stream = parsed.options.stream;
     let bytes = parsed
         .input
-        .map(webidl::BufferSource::into_bytes)
+        .map(|input| input.to_vec(scope))
         .unwrap_or_default();
 
     let Some(decode_result) = decode_text_decoder_state(scope, decoder_id, &bytes, stream) else {
diff --git a/moli-renderer-v8/src/script_vm/tests/webidl_fetch/webidl_and_transform_streams.rs b/moli-renderer-v8/src/script_vm/tests/webidl_fetch/webidl_and_transform_streams.rs
index 5a67c99794..852a73355a 100644
--- a/moli-renderer-v8/src/script_vm/tests/webidl_fetch/webidl_and_transform_streams.rs
+++ b/moli-renderer-v8/src/script_vm/tests/webidl_fetch/webidl_and_transform_streams.rs
@@ -1634,3 +1634,26 @@ fn transform_stream_caught_enqueue_strategy_error_errors_stream_but_resolves_wri
         r#"["closed:RangeError","enqueue:RangeError","readable:RangeError","ready:RangeError","write:resolved"]"#
     );
 }
+
+#[test]
+fn text_decoder_snapshots_input_after_options_conversion() {
+    let mut vm = new_storage_test_vm("https://text-decoder-input-snapshot.test/");
+    vm.eval(include_str!(
+        "../../../../tests/fixtures/text-decoder-input-snapshot.js"
+    ))
+    .expect("text decoder input snapshot contract should load");
+    vm.eval("runTextDecoderInputSnapshotContract().then(result => globalThis.__textDecoderInputSnapshotResults = result)")
+        .expect("text decoder input snapshot contract should execute");
+    let facts: serde_json::Value = serde_json::from_str(
+        &vm.eval("JSON.stringify(__textDecoderInputSnapshotResults)")
+            .expect("text decoder input snapshot results should serialize"),
+    )
+    .expect("text decoder input snapshot results should be valid JSON");
+    let checks = facts["checks"].as_array().expect("input snapshot checks");
+    let failures = checks
+        .iter()
+        .filter(|check| check["passed"] != true)
+        .collect::<Vec<_>>();
+    assert!(failures.is_empty(), "{failures:#?}");
+    assert_eq!(checks.len(), 33);
+}
diff --git a/moli-renderer-v8/src/worker/thread/tests/lifecycle/background_apis_and_worker_events.rs b/moli-renderer-v8/src/worker/thread/tests/lifecycle/background_apis_and_worker_events.rs
index 4300000245..9cf1b74503 100644
--- a/moli-renderer-v8/src/worker/thread/tests/lifecycle/background_apis_and_worker_events.rs
+++ b/moli-renderer-v8/src/worker/thread/tests/lifecycle/background_apis_and_worker_events.rs
@@ -1784,3 +1784,37 @@ async fn worker_xmlhttprequest_loadstart_handles_upload_abort_and_reopen() {
         r#"{"aborted":[["xhr-start:0:0:false","upload-abort:4:0:0:false","upload-loadend:4:0:0:false","xhr-abort:4","xhr-loadend:4","after-send:0:0"],["xhr-start:0:0:false","upload-start:0:2:true","upload-abort:4:0:0:false","upload-loadend:4:0:0:false","xhr-abort:4","xhr-loadend:4","after-send:0:0"],["xhr-start:0:0:false","upload-start:0:0:false","upload-abort:4:0:0:false","upload-loadend:4:0:0:false","xhr-abort:4","xhr-loadend:4","after-send:0:0"]],"reopened":["xhr-start:1","upload-start:0:2","xhr-start:1","after-reopen:1","load:replacement","loadend:4"]}"#
     );
 }
+
+#[tokio::test]
+async fn worker_text_decoder_snapshots_input_after_options_conversion() {
+    ensure_v8();
+    let source = [
+        include_str!("../../../../../tests/fixtures/text-decoder-input-snapshot.js"),
+        r#"
+runTextDecoderInputSnapshotContract().then(
+    result => { postMessage(result); close(); },
+    error => { postMessage({ failure: String(error) }); close(); }
+);
+"#,
+    ]
+    .join("\n");
+    let mut handle = spawn_worker(
+        source,
+        "https://text-decoder-input-snapshot.test/worker.js".into(),
+    );
+    let message = timeout(TIMEOUT, handle.recv())
+        .await
+        .expect("text decoder input snapshot contract should complete");
+    handle.terminate_and_join();
+    let facts: serde_json::Value = serde_json::from_str(&expect_post_json(
+        message.expect("worker result channel should stay open"),
+    ))
+    .expect("text decoder input snapshot results should be valid JSON");
+    let checks = facts["checks"].as_array().expect("input snapshot checks");
+    let failures = checks
+        .iter()
+        .filter(|check| check["passed"] != true)
+        .collect::<Vec<_>>();
+    assert!(failures.is_empty(), "{failures:#?}");
+    assert_eq!(checks.len(), 33);
+}
diff --git a/moli-renderer-v8/tests/fixtures/text-decoder-input-snapshot.js b/moli-renderer-v8/tests/fixtures/text-decoder-input-snapshot.js
new file mode 100644
index 0000000000..364e85680e
--- /dev/null
+++ b/moli-renderer-v8/tests/fixtures/text-decoder-input-snapshot.js
@@ -0,0 +1,138 @@
+globalThis.runTextDecoderInputSnapshotContract = async function () {
+  const checks = [];
+  function check(name, operation) {
+    try { checks.push({ name, passed: operation() === true }); }
+    catch (error) { checks.push({ name, passed: false, error: String(error) }); }
+  }
+  for (const [name, make] of [
+    ["buffer", () => {
+      const bytes = Uint8Array.of(65);
+      return { input: bytes.buffer, mutate: () => bytes[0] = 66 };
+    }],
+    ["view offset", () => {
+      const bytes = Uint8Array.of(0, 65, 0);
+      return { input: bytes.subarray(1, 2), mutate: () => bytes[1] = 66 };
+    }],
+    ["DataView offset", () => {
+      const bytes = Uint8Array.of(0, 65, 0);
+      return { input: new DataView(bytes.buffer, 1, 1), mutate: () => bytes[1] = 66 };
+    }],
+    ["shared buffer", () => {
+      const bytes = new Uint8Array(new SharedArrayBuffer(1));
+      bytes[0] = 65;
+      return { input: bytes.buffer, mutate: () => Atomics.store(bytes, 0, 66) };
+    }],
+    ["shared view offset", () => {
+      const bytes = new Uint8Array(new SharedArrayBuffer(3));
+      bytes[1] = 65;
+      return { input: bytes.subarray(1, 2), mutate: () => Atomics.store(bytes, 1, 66) };
+    }],
+  ]) {
+    check(`snapshot after options: ${name}`, () => {
+      const { input, mutate } = make();
+      let reads = 0;
+      const output = new TextDecoder().decode(input, {
+        get stream() { reads++; mutate(); return false; },
+      });
+      return reads === 1 && output === "B";
+    });
+  }
+  for (const length of [1, 10000]) {
+    for (const kind of ["buffer", "view", "DataView"]) {
+      check(`detach during options: ${kind} length=${length}`, () => {
+        const bytes = new Uint8Array(length).fill(42);
+        const input = kind === "buffer" ? bytes.buffer : kind === "view" ? bytes : new DataView(bytes.buffer);
+        let reads = 0;
+        const output = new TextDecoder().decode(input, {
+          get stream() { reads++; bytes.buffer.transfer(0); return false; },
+        });
+        return reads === 1 && output === "";
+      });
+    }
+  }
+  const invalidSources = [
+    ["null", () => null],
+    ["object", () => ({})],
+    ["array", () => []],
+    ["forged view", () => Object.create(Uint8Array.prototype)],
+    ["Proxy", () => new Proxy(Uint8Array.of(65), {})],
+    ["revoked Proxy", () => {
+      const proxy = Proxy.revocable(Uint8Array.of(65), {});
+      proxy.revoke();
+      return proxy.proxy;
+    }],
+  ];
+  for (const shared of [false, true]) {
+    for (const kind of ["buffer", "view", "DataView"]) {
+      invalidSources.push([`${shared ? "growable shared" : "resizable"} ${kind}`, () => {
+        const buffer = shared ? new SharedArrayBuffer(1, { maxByteLength: 2 }) :
+          new ArrayBuffer(1, { maxByteLength: 2 });
+        return kind === "buffer" ? buffer : kind === "view" ? new Uint8Array(buffer) : new DataView(buffer);
+      }]);
+    }
+  }
+  for (const kind of ["buffer", "view"]) {
+    invalidSources.push([`detached resizable ${kind}`, () => {
+      const buffer = new ArrayBuffer(1, { maxByteLength: 2 });
+      const view = new Uint8Array(buffer);
+      buffer.transfer(0);
+      return kind === "buffer" ? buffer : view;
+    }]);
+  }
+  for (const [name, make] of invalidSources) {
+    check(`reject before options: ${name}`, () => {
+      const input = make();
+      let reads = 0;
+      try {
+        new TextDecoder().decode(input, { get stream() { reads++; return false; } });
+        return false;
+      } catch (error) { return error instanceof TypeError && reads === 0; }
+    });
+  }
+  check("options exception identity", () => {
+    const sentinel = {};
+    try {
+      new TextDecoder().decode(Uint8Array.of(65), { get stream() { throw sentinel; } });
+      return false;
+    } catch (error) { return error === sentinel; }
+  });
+  check("undefined converts options and flushes", () => {
+    const decoder = new TextDecoder();
+    decoder.decode(Uint8Array.of(0xc9), { stream: true });
+    let reads = 0;
+    const output = decoder.decode(undefined, { get stream() { reads++; return false; } });
+    return reads === 1 && output === "\ufffd";
+  });
+  for (const kind of ["buffer", "view", "DataView", "shared buffer"]) {
+    check(`ignore author buffer getters: ${kind}`, () => {
+      const buffer = kind === "shared buffer" ? new SharedArrayBuffer(1) : new ArrayBuffer(1);
+      new Uint8Array(buffer)[0] = 65;
+      const input = kind === "view" ? new Uint8Array(buffer) : kind === "DataView" ? new DataView(buffer) : buffer;
+      let reads = 0;
+      for (const name of ["byteLength", "buffer", "byteOffset"]) {
+        Object.defineProperty(input, name, { get() { reads++; throw Error(name); } });
+      }
+      return new TextDecoder().decode(input) === "A" && reads === 0;
+    });
+  }
+  check("receiver check before options", () => {
+    let reads = 0;
+    try {
+      TextDecoder.prototype.decode.call({}, Uint8Array.of(65), { get stream() { reads++; return false; } });
+      return false;
+    } catch (error) { return error instanceof TypeError && reads === 0; }
+  });
+  check("reentrant options decode", () => {
+    const decoder = new TextDecoder();
+    let reads = 0;
+    const output = decoder.decode(Uint8Array.of(0xac), {
+      get stream() {
+        reads++;
+        decoder.decode(Uint8Array.of(0xe2, 0x82), { stream: true });
+        return false;
+      },
+    });
+    return reads === 1 && output === "\u20ac";
+  });
+  return { checks };
+};
diff --git a/moli-webidl/src/buffer_source.rs b/moli-webidl/src/buffer_source.rs
index 199a5d70c0..3c15c81565 100644
--- a/moli-webidl/src/buffer_source.rs
+++ b/moli-webidl/src/buffer_source.rs
@@ -3,7 +3,7 @@
 use crate::{Context, WebIdlConverter, WebIdlError};
 use std::sync::atomic::{AtomicU8, Ordering};
 
-/// `[AllowShared] BufferSource`, retaining the native buffer identity instead
+/// Web IDL `AllowSharedBufferSource`, retaining the native buffer identity instead
 /// of copying during conversion. Resizable and growable buffers require the
 /// separate `[AllowResizable]` annotation and are rejected here.
 pub enum AllowSharedBufferSource<'s> {