diff --git a/common/chat-auto-parser-generator.cpp b/common/chat-auto-parser-generator.cpp
index b206d83222..aab13121a2 100644
--- a/common/chat-auto-parser-generator.cpp
+++ b/common/chat-auto-parser-generator.cpp
@@ -1,4 +1,5 @@
 #include "chat-auto-parser.h"
+#include "chat-auto-parser-helpers.h"
 #include "chat-peg-parser.h"
 #include "chat.h"
 #include "common.h"
@@ -54,21 +55,13 @@ common_chat_params peg_generator::generate_parser(const common_chat_template &
         const auto & r_start = autoparser.reasoning.start;
         const auto & r_end   = autoparser.reasoning.end;
 
-        auto rtrim = [](std::string s) {
-            while (!s.empty() && (s.back() == ' ' || s.back() == '\n' ||
-                                  s.back() == '\r' || s.back() == '\t')) {
-                s.pop_back();
-            }
-            return s;
-        };
-
-        auto prompt_trimmed  = rtrim(data.prompt);
-        auto r_end_trimmed   = rtrim(r_end);
-        auto r_start_trimmed = rtrim(r_start);
+        auto prompt_trimmed  = trim_trailing_whitespace(data.prompt);
+        auto r_end_trimmed   = trim_trailing_whitespace(r_end);
+        auto r_start_trimmed = trim_trailing_whitespace(r_start);
 
         if (!r_start_trimmed.empty()) {
             if (string_ends_with(prompt_trimmed, r_end_trimmed)) {
-                auto before_end = rtrim(prompt_trimmed.substr(0, prompt_trimmed.size() - r_end_trimmed.size()));
+                auto before_end = trim_trailing_whitespace(prompt_trimmed.substr(0, prompt_trimmed.size() - r_end_trimmed.size()));
                 if (string_ends_with(before_end, r_start_trimmed)) {
                     // Start+end at prompt end — use canonical markers to preserve whitespace.
                     data.reasoning_prefill = r_start + r_end;
@@ -185,7 +178,7 @@ common_peg_parser analyze_reasoning::build_parser(parser_build_context & ctx) co
                 // Standard tag-based: optional(<think>reasoning</think>)
                 return p.optional(start + p.reasoning(p.until(end)) + end);
             }
-            // Delimiter-style (empty start): optional(reasoning[DELIMITER])
+            // Delimiter-style (empty start)
             return p.optional(p.reasoning(p.until(end)) + end);
         }
     }
diff --git a/docs/autoparser.md b/docs/autoparser.md
index 905393b08d..b2374391a1 100644
--- a/docs/autoparser.md
+++ b/docs/autoparser.md
@@ -266,8 +266,8 @@ Text is segmentized into markers and non-marker fragments using `segmentize_mark
 
 - Searches `diff.right` (output with reasoning) for the reasoning content needle
 - Uses PEG parsers to find surrounding markers:
-  - If both pre/post markers found in `diff.right` → `TAG_BASED` (both tags visible in diff = no forced close)
-  - If both found but post marker only in the full output B → `FORCED_CLOSED`
+  - If both pre/post markers found in `diff.right` → `TAG_BASED`
+  - If both found but post marker only in the full output B → `TAG_BASED` (template forces markers; handled via prefill)
   - If only post marker found → `TAG_BASED` (delimiter-style, empty start)
 - Sets `reasoning.start` and `reasoning.end`
 
@@ -349,7 +349,7 @@ Classification logic:
 
 A workaround array in `common/chat-diff-analyzer.cpp` applies post-hoc patches after analysis. Each workaround is a lambda that inspects the template source and overrides analysis results. Current workarounds:
 
-1. **Old Qwen/DeepSeek thinking templates** — source contains `content.split('</think>')`: sets `reasoning.mode = FORCED_OPEN` with `<think>`/`</think>` markers if no reasoning was detected
+1. **Old Qwen/DeepSeek thinking templates** — source contains `content.split('</think>')`: sets `reasoning.mode = TAG_BASED` with `<think>`/`</think>` markers if no reasoning was detected
 2. **Granite 3.3** — source contains specific "Write your thoughts" text: forces `TAG_BASED` reasoning with `<think>`/`</think>` and `WRAPPED_WITH_REASONING` content with `<response>`/`</response>`
 3. **Cohere Command R+** — source contains `<|CHATBOT_TOKEN|>`: sets `ALWAYS_WRAPPED` content mode if no content start is already set
 4. **Functionary 3.1** — source contains `set has_code_interpreter`: forces `PLAIN` content, specific `per_call_start/end`, clears preserved tokens to only keep Functionary-specific markers
diff --git a/tests/test-chat-auto-parser.cpp b/tests/test-chat-auto-parser.cpp
index 491522324a..e140eb8ebf 100644
--- a/tests/test-chat-auto-parser.cpp
+++ b/tests/test-chat-auto-parser.cpp
@@ -1295,7 +1295,7 @@ static void test_nemotron_reasoning_detection(testing & t) {
     t.assert_equal("reasoning_end should be '</think>\\n'", "</think>\n", analysis.reasoning.end);
 
     // Check reasoning mode detection
-    // Nemotron uses tag-based reasoning (formerly FORCED_CLOSED; prefill handles the template's forced markers)
+    // Nemotron uses tag-based reasoning; prefill handles the template's forced markers
     t.assert_equal("reasoning should be TAG_BASED", reasoning_mode::TAG_BASED, analysis.reasoning.mode);
 
     // Make sure reasoning markers don't spill over to content markers