diff --git a/aider/analytics.py b/aider/analytics.py
index d5c37c10a..59913ccbf 100644
--- a/aider/analytics.py
+++ b/aider/analytics.py
@@ -70,9 +70,17 @@ class Analytics:
     # ephemeral
     logfile = None
 
-    def __init__(self, logfile=None, permanently_disable=False):
+    def __init__(
+            self,
+            logfile=None,
+            permanently_disable=False,
+            posthog_host=None,
+            posthog_project_api_key=None
+    ):
         self.logfile = logfile
         self.get_or_create_uuid()
+        self.custom_posthog_host = posthog_host
+        self.custom_posthog_project_api_key = posthog_project_api_key
 
         if self.permanently_disable or permanently_disable or not self.asked_opt_in:
             self.disable(permanently_disable)
@@ -92,8 +100,8 @@ class Analytics:
 
         # self.mp = Mixpanel(mixpanel_project_token)
         self.ph = Posthog(
-            project_api_key=posthog_project_api_key,
-            host=posthog_host,
+            project_api_key=self.custom_posthog_project_api_key or posthog_project_api_key,
+            host=self.custom_posthog_host or posthog_host,
             on_error=self.posthog_error,
             enable_exception_autocapture=True,
             super_properties=self.get_system_info(),  # Add system info to all events
diff --git a/aider/args.py b/aider/args.py
index 0e1b13c42..0728d5938 100644
--- a/aider/args.py
+++ b/aider/args.py
@@ -582,6 +582,16 @@ def get_parser(default_config_files, git_root):
         help="Permanently disable analytics",
         default=False,
     )
+    group.add_argument(
+        "--analytics-posthog-host",
+        metavar="ANALYTICS_POSTHOG_HOST",
+        help="Send analytics to custom PostHog instance",
+    )
+    group.add_argument(
+        "--analytics-posthog-project-api-key",
+        metavar="ANALYTICS_POSTHOG_PROJECT_API_KEY",
+        help="Send analytics to custom PostHog project"
+    )
 
     #########
     group = parser.add_argument_group("Upgrading")
diff --git a/aider/history.py b/aider/history.py
index a4727b941..9836be0ca 100644
--- a/aider/history.py
+++ b/aider/history.py
@@ -63,37 +63,38 @@ class ChatSummary:
         if split_index <= min_split:
             return self.summarize_all(messages)
 
+        # Split head and tail
         head = messages[:split_index]
         tail = messages[split_index:]
 
-        sized = sized[:split_index]
-        head.reverse()
-        sized.reverse()
+        # Only size the head once
+        sized_head = sized[:split_index]
+
+        # Precompute token limit (fallback to 4096 if undefined)
+        model_max_input_tokens = self.models[0].info.get("max_input_tokens") or 4096
+        model_max_input_tokens -= 512  # reserve buffer for safety
+
         keep = []
         total = 0
 
-        # These sometimes come set with value = None
-        model_max_input_tokens = self.models[0].info.get("max_input_tokens") or 4096
-        model_max_input_tokens -= 512
-
-        for i in range(split_index):
-            total += sized[i][0]
+        # Iterate in original order, summing tokens until limit
+        for tokens, msg in sized_head:
+            total += tokens
             if total > model_max_input_tokens:
                 break
-            keep.append(head[i])
-
-        keep.reverse()
+            keep.append(msg)
+        # No need to reverse lists back and forth
 
         summary = self.summarize_all(keep)
 
-        tail_tokens = sum(tokens for tokens, msg in sized[split_index:])
+        # If the combined summary and tail still fits, return directly
         summary_tokens = self.token_count(summary)
-
-        result = summary + tail
+        tail_tokens = sum(tokens for tokens, _ in sized[split_index:])
         if summary_tokens + tail_tokens < self.max_tokens:
-            return result
+            return summary + tail
 
-        return self.summarize_real(result, depth + 1)
+        # Otherwise recurse with increased depth
+        return self.summarize_real(summary + tail, depth + 1)
 
     def summarize_all(self, messages):
         content = ""
diff --git a/aider/main.py b/aider/main.py
index 83855bad7..00427cc39 100644
--- a/aider/main.py
+++ b/aider/main.py
@@ -633,7 +633,12 @@ def main(argv=None, input=None, output=None, force_git_root=None, return_coder=F
         )
         os.environ["OPENAI_ORGANIZATION"] = args.openai_organization_id
 
-    analytics = Analytics(logfile=args.analytics_log, permanently_disable=args.analytics_disable)
+    analytics = Analytics(
+        logfile=args.analytics_log,
+        permanently_disable=args.analytics_disable,
+        posthog_host=args.analytics_posthog_host,
+        posthog_project_api_key=args.analytics_posthog_project_api_key
+    )
     if args.analytics is not False:
         if analytics.need_to_ask(args.analytics):
             io.tool_output(
diff --git a/aider/website/assets/sample.aider.conf.yml b/aider/website/assets/sample.aider.conf.yml
index 3e2082cf5..171d4a021 100644
--- a/aider/website/assets/sample.aider.conf.yml
+++ b/aider/website/assets/sample.aider.conf.yml
@@ -298,6 +298,12 @@
 ## Permanently disable analytics
 #analytics-disable: false
 
+## PostHog host (default: https://us.i.posthog.com)
+#analytics-posthog-host: xxx
+
+## PostHog project api key (default: phc_99T7muzafUMMZX15H8XePbMSreEUzahHbtWjy3l5Qbv)
+#analytics-posthog-project-api-key: xxx
+
 ############
 # Upgrading:
 
diff --git a/aider/website/docs/more/analytics.md b/aider/website/docs/more/analytics.md
index adb0ddebd..74de05213 100644
--- a/aider/website/docs/more/analytics.md
+++ b/aider/website/docs/more/analytics.md
@@ -105,6 +105,12 @@ If you want to just log analytics without reporting them, you can do:
 aider --analytics-log filename.jsonl --no-analytics
 ```
 
+### Sending analytics to custom PostHog project or installation
+
+Aider uses PostHog for analytics collection. You can configure aider to send analytics to your own PostHog project or a custom PostHog installation using these parameters:
+
+- `--analytics-posthog-project-api-key KEY` - Set a custom PostHog project API key
+- `--analytics-posthog-host HOST` - Set a custom PostHog host (default is app.posthog.com)
 
 ## Reporting issues