diff --git a/src/ci.rs b/src/ci.rs
index c60becd..833c1b2 100644
--- a/src/ci.rs
+++ b/src/ci.rs
@@ -23,6 +23,7 @@ struct CiArgs {
     duration: Option<Duration>,
     format: Option<FormatType>,
     output: Option<String>,
+    diff_only: bool,
     /// Bytes per second. Fail if the rolling-window growth rate exceeds this.
     growth_rate: Option<u64>,
     sample_interval: Option<u64>,
@@ -54,6 +55,11 @@ pub fn ci_main(args: &[String]) -> i32 {
         None
     };
 
+    if parsed.diff_only && !parsed.leak_check {
+        eprintln!("error: --diff-only requires --leak-check to be active");
+        return 1;
+    }
+
     let start = Instant::now();
     let poll_interval = Duration::from_millis(parsed.sample_interval.unwrap_or(1000));
     let mut sys = System::new_all();
@@ -163,7 +169,13 @@ pub fn ci_main(args: &[String]) -> i32 {
     // Export report if requested.
     if let Some(ref format_type) = parsed.format {
         if let Some(current_heap) = last_captured_heap {
-            let blocks = current_heap;
+            let mut blocks = current_heap;
+
+            if parsed.diff_only {
+                if let Some(ref prev) = baseline {
+                    blocks = blocks.into_iter().filter(|b| !prev.contains(b)).collect();
+                }
+            }
 
             let target_path = parsed.output.clone().unwrap_or_else(|| match format_type {
                 FormatType::Json => "heap_dump.json".to_string(),
@@ -227,6 +239,7 @@ fn resolve_target(target: &CiTarget) -> Result<(u32, Option<Child>), AppError> {
 fn parse_ci_args(args: &[String]) -> Result<CiArgs, AppError> {
     let mut max_memory = None;
     let mut leak_check = false;
+    let mut diff_only = false;
     let mut duration = None;
     let mut target = None;
     let mut format = None;
@@ -252,6 +265,10 @@ fn parse_ci_args(args: &[String]) -> Result<CiArgs, AppError> {
                 leak_check = true;
                 i += 1;
             }
+            "--diff-only" => {
+                diff_only = true;
+                i += 1;
+            }
             "--duration" => {
                 if i + 1 < args.len() {
                     let val = args[i + 1]
@@ -357,6 +374,7 @@ fn parse_ci_args(args: &[String]) -> Result<CiArgs, AppError> {
         target,
         max_memory,
         leak_check,
+        diff_only,
         duration,
         format,
         output,
diff --git a/src/os/windows.rs b/src/os/windows.rs
index c5d0d85..cfc4543 100644
--- a/src/os/windows.rs
+++ b/src/os/windows.rs
@@ -139,6 +139,7 @@ pub fn walk_regions(pid: u32) -> Vec<Region> {
 /// A `Vec<HeapBlock>` with address, size, free status, and page protection
 /// for each parsed heap block.
 pub fn walk_heap(pid: u32) -> Vec<HeapBlock> {
+    use std::time::{Duration, Instant};
     use windows::Win32::Foundation::CloseHandle;
     use windows::Win32::System::Diagnostics::Debug::ReadProcessMemory;
     use windows::Win32::System::Diagnostics::ToolHelp::{
@@ -150,7 +151,6 @@ pub fn walk_heap(pid: u32) -> Vec<HeapBlock> {
     use windows::Win32::System::Threading::{
         OpenProcess, PROCESS_QUERY_INFORMATION, PROCESS_VM_READ,
     };
-    use std::time::{Duration, Instant};
 
     // --- tunable safety limits ---
     const MAX_BLOCKS_PER_HEAP: usize = 100_000;
@@ -218,7 +218,9 @@ pub fn walk_heap(pid: u32) -> Vec<HeapBlock> {
                 }
                 if blocks_this_heap >= MAX_BLOCKS_PER_HEAP {
                     // likely corrupted/hostile heap metadata — stop this heap, move to next
-                    eprintln!("walk_heap: heap at {heap_base:#x} exceeded block cap, skipping rest");
+                    eprintln!(
+                        "walk_heap: heap at {heap_base:#x} exceeded block cap, skipping rest"
+                    );
                     break;
                 }
 
diff --git a/src/types.rs b/src/types.rs
index 621c6fd..bf3fc44 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -50,7 +50,7 @@ pub enum RegionProtect {
     Other,
 }
 
-#[derive(Clone, Debug, Serialize)]
+#[derive(Clone, Debug, PartialEq, Serialize)]
 pub struct HeapBlock {
     pub address: usize,
     pub size: usize,