common/parser: add proper reasoning tag prefill reading

common/arg.cpp

@@ -1830,23 +1830,23 @@ common_params_context common_params_parser_init(common_params & params, llama_ex
     ).set_sparam());
     add_opt(common_arg(
         {"--grammar"}, "GRAMMAR",
-        string_format("BNF-like grammar to constrain generations (see samples in grammars/ dir) (default: '%s')", params.sampling.grammar.c_str()),
+        "BNF-like grammar to constrain generations (see samples in grammars/ dir)",
         [](common_params & params, const std::string & value) {
-            params.sampling.grammar = value;
+            params.sampling.grammar = {COMMON_GRAMMAR_TYPE_USER, value};
         }
     ).set_sparam());
     add_opt(common_arg(
         {"--grammar-file"}, "FNAME",
         "file to read grammar from",
         [](common_params & params, const std::string & value) {
-            params.sampling.grammar = read_file(value);
+            params.sampling.grammar = {COMMON_GRAMMAR_TYPE_USER, read_file(value)};
         }
     ).set_sparam());
     add_opt(common_arg(
         {"-j", "--json-schema"}, "SCHEMA",
         "JSON schema to constrain generations (https://json-schema.org/), e.g. `{}` for any JSON object\nFor schemas w/ external $refs, use --grammar + example/json_schema_to_grammar.py instead",
         [](common_params & params, const std::string & value) {
-            params.sampling.grammar = json_schema_to_grammar(json::parse(value));
+            params.sampling.grammar = {COMMON_GRAMMAR_TYPE_OUTPUT_FORMAT, json_schema_to_grammar(json::parse(value))};
         }
     ).set_sparam());
     add_opt(common_arg(
@@ -1863,7 +1863,7 @@ common_params_context common_params_parser_init(common_params & params, llama_ex
                 std::istreambuf_iterator<char>(),
                 std::back_inserter(schema)
             );
-            params.sampling.grammar = json_schema_to_grammar(json::parse(schema));
+            params.sampling.grammar = {COMMON_GRAMMAR_TYPE_OUTPUT_FORMAT, json_schema_to_grammar(json::parse(schema))};
         }
     ).set_sparam());
     add_opt(common_arg(

common/chat-auto-parser-generator.cpp

@@ -1,3 +1,4 @@
+#include "chat-auto-parser-helpers.h"
 #include "chat-auto-parser.h"
 #include "chat-peg-parser.h"
 #include "chat.h"
@@ -23,31 +24,30 @@ static void foreach_function(const json & tools, const std::function<void(const
 
 namespace autoparser {
 
-parser_build_context::parser_build_context(common_chat_peg_builder & p, const templates_params & inputs) :
+parser_build_context::parser_build_context(common_chat_peg_builder & p, const generation_params & inputs) :
     p(p),
     inputs(inputs),
     reasoning_parser(p.eps()) {}
 
 common_chat_params peg_generator::generate_parser(const common_chat_template &    tmpl,
-                                                  const struct templates_params & inputs) {
+                                                  const struct generation_params & inputs) {
     // Run differential analysis to extract template structure
     struct autoparser autoparser;
     autoparser.analyze_template(tmpl);
     return generate_parser(tmpl, inputs, autoparser);
 }
 
 common_chat_params peg_generator::generate_parser(const common_chat_template &    tmpl,
-                                                  const struct templates_params & inputs,
+                                                  const struct generation_params & inputs,
                                                   const autoparser &              autoparser) {
-    // Build the parser using the analysis results
-    auto parser = autoparser.build_parser(inputs);
-
     // Create the result structure
     common_chat_params data;
     data.prompt           = common_chat_template_direct_apply(tmpl, inputs);
     data.format           = COMMON_CHAT_FORMAT_PEG_NATIVE;
     data.preserved_tokens = autoparser.preserved_tokens;
-    data.parser           = parser.save();
+
+    auto parser = autoparser.build_parser(inputs);
+    data.parser = parser.save();
 
     // Build grammar if tools are present
     bool has_tools =
@@ -82,44 +82,38 @@ common_chat_params peg_generator::generate_parser(const common_chat_template &
     return data;
 }
 
-common_peg_arena autoparser::build_parser(const templates_params & inputs) const {
+common_peg_arena autoparser::build_parser(const generation_params & inputs) const {
     if (!analysis_complete) {
         throw std::invalid_argument("Cannot call build_parser on autoparser without performing analysis first, call analyze_template(...)");
     }
     return build_chat_peg_parser([&](common_chat_peg_builder & p) {
-        // If the template uses Python dict format (single-quoted strings in JSON structures),
-        // pre-register a json-string rule that accepts both quote styles. This must happen
-        // before any call to p.json() so that all JSON parsing inherits the flexible rule.
-        if (tools.format.uses_python_dicts) {
-            p.rule("json-string", p.quoted_string());
-        }
-
         parser_build_context ctx(p, inputs);
         bool                 extract_reasoning = inputs.reasoning_format != COMMON_REASONING_FORMAT_NONE;
-        bool                 enable_thinking   = inputs.enable_thinking;
 
-        ctx.extracting_reasoning = extract_reasoning && enable_thinking && reasoning.mode != reasoning_mode::NONE;
+        ctx.extracting_reasoning = extract_reasoning && reasoning.mode != reasoning_mode::NONE;
         ctx.content              = &content;
 
         // Build reasoning parser
         ctx.reasoning_parser = reasoning.build_parser(ctx);
 
+        auto parser = p.eps();
+
         bool has_tools           = inputs.tools.is_array() && !inputs.tools.empty();
         bool has_response_format = inputs.json_schema.is_object() && !inputs.json_schema.empty();
 
         if (has_response_format) {
             auto response_format = p.rule("response-format", p.content(p.schema(p.json(), "response-format-schema", inputs.json_schema)));
-            return ctx.reasoning_parser + p.space() + p.choice({
+            parser = ctx.reasoning_parser + p.space() + p.choice({
                 p.literal("```json") + p.space() + response_format + p.space() + p.literal("```"),
                 response_format
             }) + p.end();
+        } else if (has_tools && inputs.tool_choice != COMMON_CHAT_TOOL_CHOICE_NONE && jinja_caps.supports_tool_calls) {
+            parser = tools.build_parser(ctx);
+        } else {
+            parser = content.build_parser(ctx);
         }
-
-        if (has_tools && inputs.tool_choice != COMMON_CHAT_TOOL_CHOICE_NONE && jinja_caps.supports_tool_calls) {
-            return tools.build_parser(ctx);
-        }
-
-        return content.build_parser(ctx);
+        parser = wrap_for_generation_prompt(p, parser, inputs, reasoning.start);
+        return parser;
     });
 }
 
@@ -130,24 +124,15 @@ common_peg_parser analyze_reasoning::build_parser(parser_build_context & ctx) co
         return p.eps();
     }
 
-    bool thinking_forced_open   = (mode == reasoning_mode::FORCED_OPEN);
-    bool thinking_forced_closed = (mode == reasoning_mode::FORCED_CLOSED);
-
-    if (thinking_forced_open || thinking_forced_closed) {
-        // Thinking is forced open OR forced closed with enable_thinking=true
-        // In both cases, expect only the closing tag (opening was in template)
-        // However, since we might have incorrectly detected the open/close pattern,
-        // we admit an optional starting marker
-        return p.optional(p.literal(start)) + p.reasoning(p.until(end)) + end;
-    }
     if (mode == reasoning_mode::TAG_BASED || mode == reasoning_mode::TOOLS_ONLY) {
-        // Standard tag-based reasoning OR tools-only mode (reasoning appears with tools)
-        // Both use the same tag-based pattern if markers are available
-        if (!start.empty() && !end.empty()) {
-            return p.optional(start + p.reasoning(p.until(end)) + end);
+        if (!end.empty()) {
+            if (!start.empty()) {
+                // Standard tag-based: optional(<think>reasoning</think>)
+                return p.optional(start + p.reasoning(p.until(end)) + end + p.space());
+            }
+            // Delimiter-style (empty start)
+            return p.optional(p.reasoning(p.until(end)) + end + p.space());
         }
-    } else if (mode == reasoning_mode::DELIMITER) {
-        return p.optional(p.reasoning(p.until(end)) + end);
     }
 
     return p.eps();
@@ -335,7 +320,7 @@ common_peg_parser analyze_tools::build_tool_parser_tag_tagged(parser_build_conte
                                                                      "tool-" + name + "-arg-" + param_name + "-schema",
                                                                      param_schema, true)) :
                                     p.tool_arg_json_value(p.schema(
-                                        p.json(), "tool-" + name + "-arg-" + param_name + "-schema", param_schema, format.uses_python_dicts)) +
+                                        p.json(), "tool-" + name + "-arg-" + param_name + "-schema", param_schema, false)) +
                                         p.space()) +
                 p.tool_arg_close(p.literal(arguments.value_suffix)));
 

common/chat-auto-parser-helpers.cpp

@@ -1,9 +1,11 @@
 #include "chat-auto-parser-helpers.h"
 
 #include "chat-auto-parser.h"
+#include "chat-peg-parser.h"
 #include "chat.h"
 #include "log.h"
 #include "nlohmann/json.hpp"
+#include "peg-parser.h"
 
 #include <cctype>
 #include <numeric>
@@ -291,10 +293,26 @@ std::vector<segment> prune_whitespace_segments(const std::vector<segment> & segm
     return result;
 }
 
+common_peg_parser wrap_for_generation_prompt(common_chat_peg_builder &             p,
+                                             const common_peg_parser &             prs,
+                                             const autoparser::generation_params & inputs,
+                                             const std::string &                   reasoning_start) {
+    auto parser = prs;
+    if (!inputs.generation_prompt.empty()) {
+        size_t end_pos = inputs.generation_prompt.size();
+        if (!reasoning_start.empty() && inputs.generation_prompt.find(reasoning_start) != std::string::npos) {
+            end_pos = inputs.generation_prompt.find(reasoning_start);
+        }
+        std::string cut_genprompt = inputs.generation_prompt.substr(0, end_pos);
+        parser                    = p.literal(cut_genprompt) + parser;
+    }
+    return parser;
+}
+
 namespace autoparser {
 
 std::string apply_template(const common_chat_template & tmpl, const template_params & params) {
-    templates_params tmpl_params;
+    generation_params tmpl_params;
     tmpl_params.messages              = params.messages;
     tmpl_params.tools                 = params.tools;
     tmpl_params.add_generation_prompt = params.add_generation_prompt;

common/chat-auto-parser-helpers.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "chat-auto-parser.h"
+#include "peg-parser.h"
 #include <functional>
 #include <optional>
 #include <string>
@@ -57,6 +58,11 @@ std::vector<segment> segmentize_markers(const std::string & text);
 //                                   (MARKER, "</function>"), (MARKER, "</tool_call>") ]
 std::vector<segment> prune_whitespace_segments(const std::vector<segment> & segments);
 
+// Wrap parser with generation prompt parser
+common_peg_parser wrap_for_generation_prompt(common_chat_peg_builder &             p,
+                                             const common_peg_parser &             prs,
+                                             const autoparser::generation_params & inputs,
+                                             const std::string &                   reasoning_start = {});
 namespace autoparser {
 
 // Apply a template with the given parameters, returning the rendered string (empty on failure)

common/chat-auto-parser.h

@@ -50,7 +50,7 @@ namespace autoparser {
 // High-level params for parser generation
 // ============================================================================
 
-struct templates_params {
+struct generation_params {
     json                                  messages;
     json                                  tools;
     common_chat_tool_choice               tool_choice = COMMON_CHAT_TOOL_CHOICE_AUTO;
@@ -62,6 +62,7 @@ struct templates_params {
     bool                                  add_generation_prompt = false;
     bool                                  enable_thinking       = true;
     std::chrono::system_clock::time_point now                   = std::chrono::system_clock::now();
+    std::string                           generation_prompt;
     json                                  extra_context;
     bool                                  add_bos       = false;
     bool                                  add_eos       = false;
@@ -77,11 +78,7 @@ struct templates_params {
 // Reasoning handling mode (derived from R1-R3 comparisons)
 enum class reasoning_mode {
     NONE,           // No reasoning markers detected
-    TAG_BASED,      // Standard tag-based: <think>...</think>
-    DELIMITER,      // Delimiter-based: [BEGIN FINAL RESPONSE] (reasoning ends at delimiter)
-    FORCED_OPEN,    // Template ends with open reasoning tag (empty start, non-empty end)
-    FORCED_CLOSED,  // Template ends with open reasoning tag on enabled thinking but
-                    // with both opened and closed tag for disabled thinking
+    TAG_BASED,      // Tag-based: <think>...</think> (start can be empty for delimiter-style)
     TOOLS_ONLY      // Only reason on tool calls, not on normal content
 };
 
@@ -91,12 +88,6 @@ inline std::ostream & operator<<(std::ostream & os, const reasoning_mode & mode)
             return os << "NONE";
         case reasoning_mode::TAG_BASED:
             return os << "TAG_BASED";
-        case reasoning_mode::DELIMITER:
-            return os << "DELIMITER";
-        case reasoning_mode::FORCED_OPEN:
-            return os << "FORCED_OPEN";
-        case reasoning_mode::FORCED_CLOSED:
-            return os << "FORCED_CLOSED";
         case reasoning_mode::TOOLS_ONLY:
             return os << "TOOLS_ONLY";
         default:
@@ -184,7 +175,6 @@ struct tool_format_analysis {
 
     bool fun_name_is_key = false;       // In JSON format function name is JSON key, i.e. { "<funname>": { ... arguments ... } }
     bool tools_array_wrapped = false;   // Tool calls wrapped in JSON array [...]
-    bool uses_python_dicts = false;     // Tool call args use Python dict format (single-quoted strings)
 
     std::string              function_field = "function";
     std::string              name_field     = "name";
@@ -225,12 +215,12 @@ struct analyze_content;
 
 struct parser_build_context {
     common_chat_peg_builder & p;
-    const templates_params &          inputs;
+    const generation_params &          inputs;
     common_peg_parser                 reasoning_parser;
     bool                              extracting_reasoning = false;
     const analyze_content *           content              = nullptr;
 
-    parser_build_context(common_chat_peg_builder & p, const templates_params & inputs);
+    parser_build_context(common_chat_peg_builder & p, const generation_params & inputs);
 };
 
 // ============================================================================
@@ -260,6 +250,7 @@ struct analyze_reasoning : analyze_base {
 
     analyze_reasoning() = default;
     analyze_reasoning(const common_chat_template & tmpl, bool supports_tools);
+    analyze_reasoning(std::string start_, std::string end_) : start(std::move(start_)), end(std::move(end_)) {}
 
     common_peg_parser build_parser(parser_build_context & ctx) const override;
 
@@ -381,7 +372,7 @@ struct autoparser {
     void analyze_template(const common_chat_template & tmpl);
 
     // Build the PEG parser for this template
-    common_peg_arena build_parser(const templates_params & inputs) const;
+    common_peg_arena build_parser(const generation_params & inputs) const;
 
   private:
     // Collect tokens from entire analysis to preserve
@@ -395,10 +386,10 @@ struct autoparser {
 class peg_generator {
   public:
     static common_chat_params generate_parser(const common_chat_template &    tmpl,
-                                              const struct templates_params & inputs);
+                                              const struct generation_params & inputs);
 
     static common_chat_params generate_parser(const common_chat_template &    tmpl,
-                                              const struct templates_params & inputs,
+                                              const struct generation_params & inputs,
                                               const autoparser &              autoparser);
 };