Fix number partial parsing issue

common/chat-peg-parser.h

@@ -77,7 +77,7 @@ class common_chat_peg_unified_builder : public common_chat_peg_builder {
 
     // Use for schema-declared string types - won't be treated as potential JSON container
     common_peg_parser tool_arg_string_value(const common_peg_parser & p) { return tag(TOOL_ARG_STRING_VALUE, p); }
-    common_peg_parser tool_arg_json_value(const common_peg_parser & p) { return tag(TOOL_ARG_VALUE, p); }
+    common_peg_parser tool_arg_json_value(const common_peg_parser & p) { return atomic(tag(TOOL_ARG_VALUE, p)); }
 
     // Legacy-compatible helper for building standard JSON tool calls
     // Used by tests and manual parsers

common/peg-parser.cpp

@@ -1307,7 +1307,11 @@ common_peg_parser common_peg_parser_builder::json_number() {
         auto int_part = choice({ literal("0"), sequence({ digit1_9, chars("[0-9]", 0, -1) }) });
         auto frac     = sequence({ literal("."), digits });
         auto exp      = sequence({ choice({ literal("e"), literal("E") }), optional(chars("[+-]", 1, 1)), digits });
-        return sequence({ optional(literal("-")), int_part, optional(frac), optional(exp), space() });
+        // Negative lookahead: only commit the number when the next character can't extend it.
+        // At EOF in partial mode, chars returns NEED_MORE → negate propagates NEED_MORE → number not committed.
+        // This prevents premature commits of partial numbers (e.g. "3" when "3.14" is incoming).
+        auto not_number_continuation = negate(chars("[0-9.eE+-]", 1, 1));
+        return sequence({ optional(literal("-")), int_part, optional(frac), optional(exp), not_number_continuation, space() });
     });
 }
 

tests/test-chat.cpp

@@ -355,6 +355,21 @@ static common_chat_tool magic_int_tool{
     })",
 };
 
+static common_chat_tool amount_tool{
+    /* .name = */ "amount",
+    /* .description = */ "Amount converter",
+    /* .parameters = */ R"({
+        "type": "object",
+        "properties": {
+            "orig": {
+                "type": "number"
+            }
+        },
+        "required": ["orig"]
+    })",
+};
+
+
 static common_chat_tool string_param_tool{
     /* .name = */ "string_param",
     /* .description = */ "Tool with string parameter for testing",
@@ -2274,6 +2289,40 @@ static void test_template_output_peg_parsers(bool detailed_debug) {
             })
             .run();
 
+            tst.test(
+               "Test negative number\n"
+               "</think>\n"
+               "<tool_call>\n"
+               "<function=magic_int>\n"
+               "<parameter=ref>\n-14\n</parameter>\n"
+               "</function>\n"
+               "</tool_call>")
+            .enable_thinking(true)
+            .reasoning_format(COMMON_REASONING_FORMAT_DEEPSEEK)
+            .tools({ magic_int_tool })
+            .expect_reasoning("Test negative number")
+            .expect_tool_calls({
+                { "magic_int", R"({ "ref" : -14 })", {} }
+            })
+            .run();
+
+            tst.test(
+               "Test decimal number\n"
+               "</think>\n"
+               "<tool_call>\n"
+               "<function=amount>\n"
+               "<parameter=orig>\n3.14\n</parameter>\n"
+               "</function>\n"
+               "</tool_call>")
+            .enable_thinking(true)
+            .reasoning_format(COMMON_REASONING_FORMAT_DEEPSEEK)
+            .tools({ amount_tool })
+            .expect_reasoning("Test decimal number")
+            .expect_tool_calls({
+                { "amount", R"({ "orig" : 3.14 })", {} }
+            })
+            .run();
+
     }
 }