diff --git a/c2rust-postprocess/postprocess/transforms/base.py b/c2rust-postprocess/postprocess/transforms/base.py
index 5ce27c6781..8476c6e49a 100644
--- a/c2rust-postprocess/postprocess/transforms/base.py
+++ b/c2rust-postprocess/postprocess/transforms/base.py
@@ -36,7 +36,7 @@ def apply_ident(
         c_definition: CDefinition,
         identifier: str,
         update_rust: bool = True,
-    ) -> None:
+    ) -> str | None:
         """
         Implementations should apply transform to a single Rust definition
         with the given identifier.
diff --git a/c2rust-postprocess/postprocess/transforms/comments.py b/c2rust-postprocess/postprocess/transforms/comments.py
index 4bf5c644a2..06cecee46e 100644
--- a/c2rust-postprocess/postprocess/transforms/comments.py
+++ b/c2rust-postprocess/postprocess/transforms/comments.py
@@ -11,6 +11,7 @@
 )
 from postprocess.models import AbstractGenerativeModel, api_key_from_env
 from postprocess.transforms.base import AbstractTransform, TransformError
+from postprocess.transforms.trim import TrimTransform
 from postprocess.utils import get_highlighted_rust, remove_backticks
 
 # TODO: get from model
@@ -73,6 +74,7 @@ def __init__(self, cache: AbstractCache, model: AbstractGenerativeModel):
         super().__init__(SYSTEM_INSTRUCTION)
         self.cache = cache
         self.model = model
+        self.trim_transform = TrimTransform(cache, model)
 
     def apply_ident(
         self,
@@ -86,8 +88,7 @@ def apply_ident(
         if rust_comments:
             logging.info(
                 f"Skipping Rust fn {identifier} with existing comments:\
-                \n{rust_comments} in\
-                \n{rust_definition}"
+                \n{get_highlighted_rust(rust_definition)}"
             )
             return
 
@@ -98,6 +99,31 @@ def apply_ident(
             logging.info(f"Skipping C function without comments: {identifier}")
             return
 
+        match self.trim_transform.apply_ident(
+            rust_source_file=rust_source_file,
+            rust_definition=rust_definition,
+            c_definition=c_definition,
+            identifier=identifier,
+            update_rust=False,  # nothing to update here
+        ):
+            case None:
+                logging.error(
+                    f"Trim transform failed for {identifier}, "
+                    "skipping comments transfer"
+                )
+                return
+            case str() as trimmed_c_definition:
+                # TODO: consider trimming both the definition and the preprocessed
+                #       definition instead of possibly replacing the original
+                #       definition with the trimmed and preprocessed one.
+                c_definition = CDefinition(
+                    definition=trimmed_c_definition, preprocessed_definition=None
+                )
+            case _:
+                raise AssertionError(
+                    "Unexpected return type from trim transform: expected None or str"
+                )
+
         # TODO: make this function take a model and get prompt from model
         prompt_text = """
         Transfer the comments from the following C function to the corresponding Rust function.
@@ -169,7 +195,10 @@ def apply_ident(
             response=response,
         )
 
-        print(get_highlighted_rust(rust_fn))
+        logging.info(
+            f"Comments transferred to Rust fn {identifier}:\
+                \n{get_highlighted_rust(rust_fn)}"
+        )
 
         # TODO: move this to apply_file?
         # the challenge is that not all transforms will update Rust code
diff --git a/c2rust-postprocess/postprocess/transforms/trim.py b/c2rust-postprocess/postprocess/transforms/trim.py
new file mode 100644
index 0000000000..96ab787d80
--- /dev/null
+++ b/c2rust-postprocess/postprocess/transforms/trim.py
@@ -0,0 +1,88 @@
+import logging
+from pathlib import Path
+from textwrap import dedent
+
+from postprocess.cache import AbstractCache
+from postprocess.definitions import CDefinition, get_c_comments
+from postprocess.models import AbstractGenerativeModel
+from postprocess.transforms.base import AbstractTransform
+from postprocess.utils import remove_backticks
+
+SYSTEM_INSTRUCTION = (
+    "You are a helpful assistant that removes top-of-file prologues and"
+    " other unnecessary content such as preprocessor definitions and"
+    " comments that preceede and are unrelated to the definition of a C function."
+)
+
+
+class TrimTransform(AbstractTransform):
+    def __init__(self, cache: AbstractCache, model: AbstractGenerativeModel):
+        super().__init__(SYSTEM_INSTRUCTION)
+        self.cache = cache
+        self.model = model
+
+    def apply_ident(
+        self,
+        rust_source_file: Path,
+        rust_definition: str,
+        c_definition: CDefinition,
+        identifier: str,
+        update_rust: bool = True,
+    ) -> str | None:
+        c_comments = get_c_comments(c_definition.effective)
+        if not c_comments:
+            logging.info(
+                f"{self.__class__.__name__}: "
+                f"Skipping C function without comments: {identifier}"
+            )
+            return
+
+        prompt = """
+        Remove any prologues, preprocessor definitions, and comments that are unrelated to the definition
+        of the C function `{identifier}`. Respond with the trimmed C function definition; say nothing else.
+
+        C function:
+        ```c
+        {c_definition}
+        ```
+        """  # noqa: E501
+        prompt = dedent(
+            prompt
+        ).strip()  # note: dedent then format since the C definition isn't indented
+        prompt = prompt.format(
+            identifier=identifier, c_definition=c_definition.effective
+        )
+
+        messages = [
+            {"role": "user", "content": prompt},
+        ]
+
+        transform = self.__class__.__name__
+        model = self.model.id
+        if response := self.cache.lookup(
+            transform=transform,
+            identifier=identifier,
+            model=model,
+            messages=messages,
+        ):
+            return response
+
+        response = self.model.generate_with_tools(messages)
+
+        if response is None:
+            logging.error("Model returned no response")
+            return response
+
+        # TODO: validate that function definition is still present?
+
+        response = remove_backticks(response)
+
+        self.cache.update(
+            transform=transform,
+            identifier=identifier,
+            model=model,
+            messages=messages,
+            response=response,
+        )
+
+        return response
diff --git a/c2rust-postprocess/tests/llm-cache/CommentsTransform/partition/bf27c23abbb2f5c2d7dba1891b748252983959f5dc232f35146250b6d2d1fb29/metadata.toml b/c2rust-postprocess/tests/llm-cache/CommentsTransform/partition/37c722369b72db3bc2af3c6d410ca7c363cfe54a7adef376c1e9a7f38beffd2d/metadata.toml
similarity index 88%
rename from c2rust-postprocess/tests/llm-cache/CommentsTransform/partition/bf27c23abbb2f5c2d7dba1891b748252983959f5dc232f35146250b6d2d1fb29/metadata.toml
rename to c2rust-postprocess/tests/llm-cache/CommentsTransform/partition/37c722369b72db3bc2af3c6d410ca7c363cfe54a7adef376c1e9a7f38beffd2d/metadata.toml
index 7b0f8f2f8b..858ba90e7b 100644
--- a/c2rust-postprocess/tests/llm-cache/CommentsTransform/partition/bf27c23abbb2f5c2d7dba1891b748252983959f5dc232f35146250b6d2d1fb29/metadata.toml
+++ b/c2rust-postprocess/tests/llm-cache/CommentsTransform/partition/37c722369b72db3bc2af3c6d410ca7c363cfe54a7adef376c1e9a7f38beffd2d/metadata.toml
@@ -1,16 +1,13 @@
 transform = "CommentsTransform"
 identifier = "partition"
 model = "gemini-3-flash-preview"
-response = """/// Lomuto Partition Scheme:
-/// Partitions the array so that elements < pivot are on the left, 
-/// and elements >= pivot are on the right.
+response = """/// Partition the subarray around the last element as pivot and return pivot's final index.
 #[no_mangle]
 pub unsafe extern "C" fn partition(
     mut arr: *mut ::core::ffi::c_int,
     mut low: ::core::ffi::c_int,
     mut high: ::core::ffi::c_int,
 ) -> ::core::ffi::c_int {
-    // Partition the subarray around the last element as pivot and return pivot's final index.
     let mut pivot: ::core::ffi::c_int = *arr.offset(high as isize);
     let mut i: ::core::ffi::c_int = low - 1 as ::core::ffi::c_int;
     let mut j: ::core::ffi::c_int = low;
@@ -42,11 +39,6 @@ Respond with the Rust function definition with the transferred comments; say not
 
 C function:
 ```c
-/*
- * Lomuto Partition Scheme:
- * Partitions the array so that elements < pivot are on the left,
- * and elements >= pivot are on the right.
- */
 int partition (int arr[], int low, int high)
 {
     // Partition the subarray around the last element as pivot and return pivot's final index.
diff --git a/c2rust-postprocess/tests/llm-cache/CommentsTransform/partition/bf27c23abbb2f5c2d7dba1891b748252983959f5dc232f35146250b6d2d1fb29/response.txt b/c2rust-postprocess/tests/llm-cache/CommentsTransform/partition/37c722369b72db3bc2af3c6d410ca7c363cfe54a7adef376c1e9a7f38beffd2d/response.txt
similarity index 81%
rename from c2rust-postprocess/tests/llm-cache/CommentsTransform/partition/bf27c23abbb2f5c2d7dba1891b748252983959f5dc232f35146250b6d2d1fb29/response.txt
rename to c2rust-postprocess/tests/llm-cache/CommentsTransform/partition/37c722369b72db3bc2af3c6d410ca7c363cfe54a7adef376c1e9a7f38beffd2d/response.txt
index d4daefdadb..6542e787af 100644
--- a/c2rust-postprocess/tests/llm-cache/CommentsTransform/partition/bf27c23abbb2f5c2d7dba1891b748252983959f5dc232f35146250b6d2d1fb29/response.txt
+++ b/c2rust-postprocess/tests/llm-cache/CommentsTransform/partition/37c722369b72db3bc2af3c6d410ca7c363cfe54a7adef376c1e9a7f38beffd2d/response.txt
@@ -1,13 +1,10 @@
-/// Lomuto Partition Scheme:
-/// Partitions the array so that elements < pivot are on the left, 
-/// and elements >= pivot are on the right.
+/// Partition the subarray around the last element as pivot and return pivot's final index.
 #[no_mangle]
 pub unsafe extern "C" fn partition(
     mut arr: *mut ::core::ffi::c_int,
     mut low: ::core::ffi::c_int,
     mut high: ::core::ffi::c_int,
 ) -> ::core::ffi::c_int {
-    // Partition the subarray around the last element as pivot and return pivot's final index.
     let mut pivot: ::core::ffi::c_int = *arr.offset(high as isize);
     let mut i: ::core::ffi::c_int = low - 1 as ::core::ffi::c_int;
     let mut j: ::core::ffi::c_int = low;
diff --git a/c2rust-postprocess/tests/llm-cache/TrimTransform/partition/a4e1c68bf25ff0d12996deed99aff2f12fb77a27642c356431d8fb7bd012b82e/metadata.toml b/c2rust-postprocess/tests/llm-cache/TrimTransform/partition/a4e1c68bf25ff0d12996deed99aff2f12fb77a27642c356431d8fb7bd012b82e/metadata.toml
new file mode 100644
index 0000000000..a8ffba29a3
--- /dev/null
+++ b/c2rust-postprocess/tests/llm-cache/TrimTransform/partition/a4e1c68bf25ff0d12996deed99aff2f12fb77a27642c356431d8fb7bd012b82e/metadata.toml
@@ -0,0 +1,51 @@
+transform = "TrimTransform"
+identifier = "partition"
+model = "gemini-3-flash-preview"
+response = """int partition (int arr[], int low, int high)
+{
+    // Partition the subarray around the last element as pivot and return pivot's final index.
+    int pivot = arr[high];
+    int i = low - 1;
+
+    for (int j = low; j <= high - 1; j++) {
+        if (arr[j] <= pivot) {
+            i++;
+            // Move elements <= pivot into the left partition.
+            swap(&arr[i], &arr[j]);
+        }
+    }
+    // Place pivot just after the final element of the left partition.
+    swap(&arr[i + 1], &arr[high]);
+    return i + 1;
+}"""
+
+[[messages]]
+role = "user"
+content = """Remove any prologues, preprocessor definitions, and comments that are unrelated to the definition
+of the C function `partition`. Respond with the trimmed C function definition; say nothing else.
+
+C function:
+```c
+/* 
+ * Lomuto Partition Scheme:
+ * Partitions the array so that elements < pivot are on the left, 
+ * and elements >= pivot are on the right.
+ */
+int partition (int arr[], int low, int high)
+{
+    // Partition the subarray around the last element as pivot and return pivot's final index.
+    int pivot = arr[high];
+    int i = low - 1;
+
+    for (int j = low; j <= high - 1; j++) {
+        if (arr[j] <= pivot) {
+            i++;
+            // Move elements <= pivot into the left partition.
+            swap(&arr[i], &arr[j]);
+        }
+    }
+    // Place pivot just after the final element of the left partition.
+    swap(&arr[i + 1], &arr[high]);
+    return i + 1;
+}
+```"""
diff --git a/c2rust-postprocess/tests/llm-cache/TrimTransform/partition/a4e1c68bf25ff0d12996deed99aff2f12fb77a27642c356431d8fb7bd012b82e/response.txt b/c2rust-postprocess/tests/llm-cache/TrimTransform/partition/a4e1c68bf25ff0d12996deed99aff2f12fb77a27642c356431d8fb7bd012b82e/response.txt
new file mode 100644
index 0000000000..dd535b54b6
--- /dev/null
+++ b/c2rust-postprocess/tests/llm-cache/TrimTransform/partition/a4e1c68bf25ff0d12996deed99aff2f12fb77a27642c356431d8fb7bd012b82e/response.txt
@@ -0,0 +1,17 @@
+int partition (int arr[], int low, int high)
+{
+    // Partition the subarray around the last element as pivot and return pivot's final index.
+    int pivot = arr[high];
+    int i = low - 1;
+
+    for (int j = low; j <= high - 1; j++) {
+        if (arr[j] <= pivot) {
+            i++;
+            // Move elements <= pivot into the left partition.
+            swap(&arr[i], &arr[j]);
+        }
+    }
+    // Place pivot just after the final element of the left partition.
+    swap(&arr[i + 1], &arr[high]);
+    return i + 1;
+}
\ No newline at end of file
diff --git a/c2rust-postprocess/tests/llm-cache/TrimTransform/quickSort/7f54c99381ba6e83aae5416848fb8435ec3538f98668b1ce6d12953bc1d19990/metadata.toml b/c2rust-postprocess/tests/llm-cache/TrimTransform/quickSort/7f54c99381ba6e83aae5416848fb8435ec3538f98668b1ce6d12953bc1d19990/metadata.toml
new file mode 100644
index 0000000000..66d33d0f58
--- /dev/null
+++ b/c2rust-postprocess/tests/llm-cache/TrimTransform/quickSort/7f54c99381ba6e83aae5416848fb8435ec3538f98668b1ce6d12953bc1d19990/metadata.toml
@@ -0,0 +1,34 @@
+transform = "TrimTransform"
+identifier = "quickSort"
+model = "gemini-3-flash-preview"
+response = """void quickSort(int arr[], int low, int high)
+{
+    if (low < high) {
+        /* pi is the partitioning index; arr[pi] is now at the right place */
+        int pi = partition(arr, low, high);
+
+        /* Recursively sort elements before and after partition */
+        quickSort(arr, low, pi - 1);
+        quickSort(arr, pi + 1, high);
+    }
+}"""
+
+[[messages]]
+role = "user"
+content = """Remove any prologues, preprocessor definitions, and comments that are unrelated to the definition
+of the C function `quickSort`. Respond with the trimmed C function definition; say nothing else.
+
+C function:
+```c
+void quickSort(int arr[], int low, int high)
+{
+    if (low < high) {
+        /* pi is the partitioning index; arr[pi] is now at the right place */
+        int pi = partition(arr, low, high);
+
+        /* Recursively sort elements before and after partition */
+        quickSort(arr, low, pi - 1);
+        quickSort(arr, pi + 1, high);
+    }
+}
+```"""
diff --git a/c2rust-postprocess/tests/llm-cache/TrimTransform/quickSort/7f54c99381ba6e83aae5416848fb8435ec3538f98668b1ce6d12953bc1d19990/response.txt b/c2rust-postprocess/tests/llm-cache/TrimTransform/quickSort/7f54c99381ba6e83aae5416848fb8435ec3538f98668b1ce6d12953bc1d19990/response.txt
new file mode 100644
index 0000000000..83f9d3e6ce
--- /dev/null
+++ b/c2rust-postprocess/tests/llm-cache/TrimTransform/quickSort/7f54c99381ba6e83aae5416848fb8435ec3538f98668b1ce6d12953bc1d19990/response.txt
@@ -0,0 +1,11 @@
+void quickSort(int arr[], int low, int high)
+{
+    if (low < high) {
+        /* pi is the partitioning index; arr[pi] is now at the right place */
+        int pi = partition(arr, low, high);
+
+        /* Recursively sort elements before and after partition */
+        quickSort(arr, low, pi - 1);
+        quickSort(arr, pi + 1, high);
+    }
+}
\ No newline at end of file
diff --git a/tests/integration/tests/lua/conf.yml b/tests/integration/tests/lua/conf.yml
index 5da76c055c..82220e45bf 100644
--- a/tests/integration/tests/lua/conf.yml
+++ b/tests/integration/tests/lua/conf.yml
@@ -33,3 +33,9 @@ refactor:
 
 cargo.refactor:
   autogen: true
+
+postprocess:
+  autogen: true
+
+cargo.postprocess:
+  autogen: true