Update.

Makefile

@@ -17,6 +17,7 @@ SRC_CORE = $(SRCDIR)/r_error.c \
            $(SRCDIR)/messages.c \
            $(SRCDIR)/agent.c \
            $(SRCDIR)/bash_executor.c \
+           $(SRCDIR)/context_manager.c \
            $(SRCDIR)/main.c
 
 SRC_TOOLS = $(TOOLSDIR)/tools_init.c \

include/messages.h

@@ -21,11 +21,15 @@ r_status_t messages_add_tool_call(messages_handle msgs, struct json_object *mess
 r_status_t messages_add_tool_result(messages_handle msgs, const char *tool_call_id, const char *result);
 
 r_status_t messages_remove_last(messages_handle msgs);
+r_status_t messages_remove_range(messages_handle msgs, int start, int count);
 r_status_t messages_clear(messages_handle msgs);
 
 r_status_t messages_save(messages_handle msgs);
 r_status_t messages_load(messages_handle msgs);
 
+struct json_object *messages_get_object(messages_handle msgs, int index);
+r_status_t messages_replace_at(messages_handle msgs, int index, struct json_object *message);
+
 struct json_object *messages_to_json(messages_handle msgs);
 char *messages_to_string(messages_handle msgs);
 int messages_count(messages_handle msgs);

include/r_error.h

@@ -23,6 +23,7 @@ typedef enum {
     R_ERROR_TOOL_EXECUTION,
     R_ERROR_API_KEY_MISSING,
     R_ERROR_API_ERROR,
+    R_ERROR_CONTEXT_TOO_LONG,
     R_ERROR_MAX_ITERATIONS,
     R_ERROR_SESSION_INVALID,
     R_ERROR_UNKNOWN

src/agent.c

@@ -4,6 +4,7 @@
 #include "http_client.h"
 #include "r_config.h"
 #include "tool.h"
+#include "context_manager.h"
 #include <json-c/json.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -174,7 +175,16 @@ static struct json_object *agent_process_response(agent_handle agent, const char
     struct json_object *error_obj;
     if (json_object_object_get_ex(parsed, "error", &error_obj)) {
         const char *err_str = json_object_to_json_string(error_obj);
+        
+        // Smart error detection for context overflow
+        if (strstr(err_str, "too long") || 
+            strstr(err_str, "context_length_exceeded") ||
+            strstr(err_str, "Input is too long")) {
+            agent_set_error(agent, "CONTEXT_OVERFLOW");
+        } else {
             fprintf(stderr, "API Error: %s\n", err_str);
+        }
+        
         json_object_put(parsed);
         return NULL;
     }
@@ -297,6 +307,23 @@ char *agent_run(agent_handle agent, const char *user_message) {
         }
 
         struct json_object *choice = agent_process_response(agent, json_data);
+        
+        if (!choice && agent->last_error && strcmp(agent->last_error, "CONTEXT_OVERFLOW") == 0) {
+            if (context_manager_shrink(agent->messages) == R_SUCCESS) {
+                // Retry with shrunk history
+                free(json_data);
+                json_data = agent_build_request(agent, NULL, NULL);
+                agent->state = AGENT_STATE_RUNNING;
+                // Don't increment iteration_count for retries due to context
+                agent->iteration_count--;
+                continue;
+            } else {
+                agent_set_error(agent, "Context limit reached and cannot be shrunk further.");
+                free(json_data);
+                break;
+            }
+        }
+
         free(json_data);
         json_data = NULL;
 

src/messages.c

@@ -155,6 +155,17 @@ r_status_t messages_remove_last(messages_handle msgs) {
     return R_SUCCESS;
 }
 
+r_status_t messages_remove_range(messages_handle msgs, int start, int count) {
+    if (!msgs || !msgs->array) return R_ERROR_INVALID_ARG;
+    int size = json_object_array_length(msgs->array);
+    if (start < 0 || start >= size || count < 0) return R_ERROR_INVALID_ARG;
+    if (start + count > size) count = size - start;
+
+    json_object_array_del_idx(msgs->array, start, count);
+    messages_save(msgs);
+    return R_SUCCESS;
+}
+
 r_status_t messages_clear(messages_handle msgs) {
     if (!msgs) return R_ERROR_INVALID_ARG;
 
@@ -220,6 +231,23 @@ r_status_t messages_load(messages_handle msgs) {
     return R_SUCCESS;
 }
 
+struct json_object *messages_get_object(messages_handle msgs, int index) {
+    if (!msgs || !msgs->array) return NULL;
+    return json_object_array_get_idx(msgs->array, index);
+}
+
+r_status_t messages_replace_at(messages_handle msgs, int index, struct json_object *message) {
+    if (!msgs || !msgs->array || !message) return R_ERROR_INVALID_ARG;
+    int size = json_object_array_length(msgs->array);
+    if (index < 0 || index >= size) return R_ERROR_INVALID_ARG;
+
+    // json-c doesn't have a direct 'replace' for array by index that handles memory easily
+    // We'll use json_object_array_put_idx which replaces and puts the old object
+    json_object_array_put_idx(msgs->array, index, message);
+    messages_save(msgs);
+    return R_SUCCESS;
+}
+
 struct json_object *messages_to_json(messages_handle msgs) {
     return msgs ? msgs->array : NULL;
 }