diff --git a/common/jinja/jinja-value.cpp b/common/jinja/jinja-value.cpp
index f382a64a86..70cca62cff 100644
--- a/common/jinja/jinja-value.cpp
+++ b/common/jinja/jinja-value.cpp
@@ -385,14 +385,30 @@ const func_builtins & value_string_t::get_builtins() const {
                 return input;
             }
         }},
+        {"slice", [](const func_args & args) -> value {
+            auto & input = args.args[0];
+            if (!is_val<value_string>(input)) {
+                throw raised_exception("slice() first argument must be a string");
+            }
+            if (args.args.size() < 1 || args.args.size() > 4) {
+                throw raised_exception("slice() takes between 1 and 4 arguments");
+            }
+            int64_t start = is_val<value_int>(args.args[1]) ? args.args[1]->as_int() : 0;
+            int64_t stop  = is_val<value_int>(args.args[2]) ? args.args[2]->as_int() : -1;
+            int64_t step  = is_val<value_int>(args.args[3]) ? args.args[3]->as_int() : 1;
+            if (step == 0) {
+                throw raised_exception("slice step cannot be zero");
+            }
+            auto sliced = slice(input->as_string().str(), start, stop, step);
+            auto res = mk_val<value_string>(sliced);
+            res->val_str.mark_input_based_on(input->as_string());
+            return res;
+        }},
         {"indent", [](const func_args &) -> value {
-            throw std::runtime_error("indent builtin not implemented");
+            throw std::runtime_error("String indent builtin not implemented");
         }},
         {"join", [](const func_args &) -> value {
-            throw std::runtime_error("join builtin not implemented");
-        }},
-        {"slice", [](const func_args &) -> value {
-            throw std::runtime_error("slice builtin not implemented");
+            throw std::runtime_error("String join builtin not implemented");
         }},
     };
     return builtins;
@@ -635,15 +651,21 @@ const func_builtins & value_object_t::get_builtins() const {
 
 const func_builtins & value_null_t::get_builtins() const {
     static const func_builtins builtins = {
-        {"list", [](const func_args &) -> value {
+        {"list", [](const func_args & args) -> value {
             // fix for meetkai-functionary-medium-v3.1.jinja
-            // TODO: hide under a flag?
-            return mk_val<value_array>();
+            if (args.ctx.wrk_around.none_has_builtins) {
+                return mk_val<value_array>();
+            } else {
+                throw raised_exception("'list' builtin not supported for none type");
+            }
         }},
-        {"selectattr", [](const func_args &) -> value {
+        {"selectattr", [](const func_args & args) -> value {
             // fix for meetkai-functionary-medium-v3.1.jinja
-            // TODO: hide under a flag?
-            return mk_val<value_array>();
+            if (args.ctx.wrk_around.none_has_builtins) {
+                return mk_val<value_array>();
+            } else {
+                throw raised_exception("'selectattr' builtin not supported for none type");
+            }
         }},
     };
     return builtins;
diff --git a/common/jinja/jinja-vm.cpp b/common/jinja/jinja-vm.cpp
index 0211ef9013..94ee370029 100644
--- a/common/jinja/jinja-vm.cpp
+++ b/common/jinja/jinja-vm.cpp
@@ -109,6 +109,15 @@ value binary_expression::execute_impl(context & ctx) {
             // Special case: `anything in undefined` is `false` and `anything not in undefined` is `true`
             return mk_val<value_bool>(op.value == "not in");
         }
+        if (ctx.wrk_around.string_plus_undefined_is_string && (op.value == "+" || op.value == "~")) {
+            JJ_DEBUG("%s", "Workaround: treating undefined as empty string for string concatenation");
+            auto left_str  = left_val->is_undefined()  ? string() : left_val->as_string();
+            auto right_str = right_val->is_undefined() ? string() : right_val->as_string();
+            auto output = left_str.append(right_str);
+            auto res = mk_val<value_string>();
+            res->val_str = std::move(output);
+            return res;
+        }
         throw std::runtime_error("Cannot perform operation " + op.value + " on undefined values");
     } else if (is_val<value_null>(left_val) || is_val<value_null>(right_val)) {
         throw std::runtime_error("Cannot perform operation on null values");
@@ -628,9 +637,12 @@ value member_expression::execute_impl(context & ctx) {
     } else if (is_val<value_array>(object) || is_val<value_string>(object)) {
         if (is_val<value_int>(property)) {
             int64_t index = property->as_int();
-            JJ_DEBUG("Accessing %s index %lld", is_val<value_array>(object) ? "array" : "string", index);
+            JJ_DEBUG("Accessing %s index %lld", object->type().c_str(), index);
             if (is_val<value_array>(object)) {
                 auto & arr = object->as_array();
+                if (index < 0) {
+                    index += static_cast<int64_t>(arr.size());
+                }
                 if (index >= 0 && index < static_cast<int64_t>(arr.size())) {
                     val = arr[index];
                 }
diff --git a/common/jinja/jinja-vm.h b/common/jinja/jinja-vm.h
index 596f325194..045d45d980 100644
--- a/common/jinja/jinja-vm.h
+++ b/common/jinja/jinja-vm.h
@@ -2,6 +2,7 @@
 
 #include "jinja-lexer.h"
 #include "jinja-value.h"
+#include "jinja-workaround.h"
 
 #include <string>
 #include <vector>
@@ -52,6 +53,8 @@ struct context {
 
     std::time_t current_time; // for functions that need current time
 
+    workarounds wrk_around; // workarounds for non-standard jinja behavior
+
     context() {
         var["true"] = mk_val<value_bool>(true);
         var["false"] = mk_val<value_bool>(false);
diff --git a/common/jinja/jinja-workaround.h b/common/jinja/jinja-workaround.h
new file mode 100644
index 0000000000..766132c0ca
--- /dev/null
+++ b/common/jinja/jinja-workaround.h
@@ -0,0 +1,20 @@
+#pragma once
+
+#include "jinja-value.h"
+
+#include <string>
+#include <vector>
+
+namespace jinja {
+
+// containing workarounds for Jinja templates that rely on non-standard behavior
+
+struct workarounds {
+    // meetkai-functionary-medium-v3.1.jinja call filter on None type
+    bool none_has_builtins = true;
+
+    // Olmo calls operation + between string and undefined
+    bool string_plus_undefined_is_string = true;
+};
+
+} // namespace jinja
diff --git a/tests/test-chat-jinja.cpp b/tests/test-chat-jinja.cpp
index 72f3ee9822..61ce80d8ac 100644
--- a/tests/test-chat-jinja.cpp
+++ b/tests/test-chat-jinja.cpp
@@ -28,11 +28,32 @@ int main(void) {
 
     std::vector<std::string> failed_tests;
 
+    auto is_ignored_file = [](const std::string & filename) -> bool {
+        std::vector<std::string> ignored_files = {
+            "Apriel-",
+            "Olmo-3-7B-Instruct-Heretic-GGUF",
+        };
+        for (const auto & ignored : ignored_files) {
+            if (filename.find(ignored) != std::string::npos) {
+                return true;
+            }
+        }
+        return false;
+    };
+
     // list all files in models/templates/ and run each
     size_t test_count = 0;
-    std::string dir_path = "models/templates/";
+    size_t skip_count = 0;
+    //std::string dir_path = "models/templates/";
+    std::string dir_path = "../test-jinja/templates/";
     for (const auto & entry : std::filesystem::directory_iterator(dir_path)) {
         if (entry.is_regular_file()) {
+            if (is_ignored_file(entry.path().filename().string())) {
+                std::cout << "=== SKIPPING TEMPLATE FILE: " << entry.path().string() << " ===\n";
+                skip_count++;
+                continue;
+            }
+
             test_count++;
             std::cout << "\n\n=== RUNNING TEMPLATE FILE: " << entry.path().string() << " ===\n";
             std::ifstream infile(entry.path());
@@ -43,6 +64,7 @@ int main(void) {
                 std::cout << "Exception: " << e.what() << "\n";
                 std::cout << "=== ERROR WITH TEMPLATE FILE: " << entry.path().string() << " ===\n";
                 failed_tests.push_back(entry.path().string());
+                exit(1);
             }
         }
     }
@@ -50,6 +72,7 @@ int main(void) {
     std::cout << "\n\n=== TEST SUMMARY ===\n";
     std::cout << "Total tests run: " << test_count << "\n";
     std::cout << "Total failed tests: " << failed_tests.size() << "\n";
+    std::cout << "Total skipped tests: " << skip_count << "\n";
     for (const auto & test : failed_tests) {
         std::cout << "FAILED TEST: " << test << "\n";
     }
@@ -92,6 +115,7 @@ void run(std::string contents) {
         ],
         "bos_token": "<s>",
         "eos_token": "</s>",
+        "tools": [],
         "functions": "",
         "datetime": ""
     })";