diff --git a/examples/wchess/libwchess/CMakeLists.txt b/examples/wchess/libwchess/CMakeLists.txt
index 7c89883d..b785fb2c 100644
--- a/examples/wchess/libwchess/CMakeLists.txt
+++ b/examples/wchess/libwchess/CMakeLists.txt
@@ -3,14 +3,15 @@ add_library(libwchess
     WChess.h
     Chessboard.cpp
     Chessboard.h
-    )
+)
 
 target_link_libraries(libwchess
     PUBLIC
     whisper
+    common
 )
 
 target_include_directories(libwchess
     PUBLIC
     "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>"
-    )
+)
diff --git a/examples/wchess/libwchess/WChess.cpp b/examples/wchess/libwchess/WChess.cpp
index 249b7b53..99fb6d5e 100644
--- a/examples/wchess/libwchess/WChess.cpp
+++ b/examples/wchess/libwchess/WChess.cpp
@@ -1,49 +1,48 @@
 #include "WChess.h"
+#include "Chessboard.h"
 #include "grammar-parser.h"
 #include "common.h"
 #include <thread>
 
-Chess::Chess(whisper_context * ctx,
+WChess::WChess(whisper_context * ctx,
         const whisper_full_params & wparams,
-        StatusSetter status_setter,
-        ISRunning running,
-        AudioGetter audio,
-        MovesSetter m_moveSetter)
+        callbacks cb,
+        settings s)
         : m_ctx(ctx)
         , m_wparams(wparams)
-        , m_status_setter(status_setter)
-        , m_running(running)
-        , m_audio(audio)
-        , m_moveSetter( m_moveSetter)
+        , m_cb(cb)
+        , m_settings(s)
+        , m_board(new Chessboard())
 {}
 
-void Chess::set_status(const char * msg) {
-    if (m_status_setter) (*m_status_setter)(msg);
+WChess::~WChess() = default;
+
+void WChess::set_status(const std::string& msg) const {
+    if (m_cb.set_status) (*m_cb.set_status)(msg);
 }
 
-void Chess::set_moves(const std::string& moves) {
-    if (m_moveSetter) (*m_moveSetter)(moves);
+void WChess::set_moves(const std::string& moves) const {
+    if (m_cb.set_moves) (*m_cb.set_moves)(moves);
 }
 
-bool Chess::check_running() {
-    if (m_running) return (*m_running)();
+bool WChess::check_running() const {
+    if (m_cb.check_running) return (*m_cb.check_running)();
     return false;
 }
 
-void Chess::get_audio(int ms, std::vector<float>& pcmf32) {
-    if (m_audio) (*m_audio)(ms, pcmf32);
+void WChess::get_audio(int ms, std::vector<float>& pcmf32) const {
+    if (m_cb.get_audio) (*m_cb.get_audio)(ms, pcmf32);
 }
 
-std::string Chess::stringifyBoard() {
-    return m_board.stringifyBoard();
+std::string WChess::stringify_board() const {
+    return m_board->stringifyBoard();
 }
 
-void Chess::run() {
+void WChess::run() {
     set_status("loading data ...");
 
     bool have_prompt  = false;
     bool ask_prompt   = true;
-    bool print_energy = false;
 
     float logprob_min0 = 0.0f;
     float logprob_min  = 0.0f;
@@ -87,13 +86,6 @@ void Chess::run() {
         m_wparams.grammar_penalty = 100.0;
     }
 
-    const int32_t vad_ms     = 2000;
-    const int32_t prompt_ms  = 5000;
-    const int32_t command_ms = 4000;
-
-    const float vad_thold  = 0.1f;
-    const float freq_thold = -1.0f;
-
     while (check_running()) {
         // delay
         std::this_thread::sleep_for(std::chrono::milliseconds(100));
@@ -115,14 +107,14 @@ void Chess::run() {
         int64_t t_ms = 0;
 
         {
-            get_audio(vad_ms, pcmf32_cur);
+            get_audio(m_settings.vad_ms, pcmf32_cur);
 
-            if (::vad_simple(pcmf32_cur, WHISPER_SAMPLE_RATE, 1000, vad_thold, freq_thold, print_energy)) {
+            if (::vad_simple(pcmf32_cur, WHISPER_SAMPLE_RATE, 1000, m_settings.vad_thold, m_settings.freq_thold, m_settings.print_energy)) {
                 fprintf(stdout, "%s: Speech detected! Processing ...\n", __func__);
                 set_status("Speech detected! Processing ...");
 
                 if (!have_prompt) {
-                    get_audio(prompt_ms, pcmf32_cur);
+                    get_audio(m_settings.prompt_ms, pcmf32_cur);
 
                     m_wparams.i_start_rule    = grammar_parsed.symbol_ids.at("prompt");
                     const auto txt = ::trim(transcribe(pcmf32_cur, logprob_min, logprob_sum, n_tokens, t_ms));
@@ -151,7 +143,7 @@ void Chess::run() {
                         have_prompt = true;
                     }
                 } else {
-                    get_audio(command_ms, pcmf32_cur);
+                    get_audio(m_settings.command_ms, pcmf32_cur);
 
                     // prepend 3 second of silence
                     pcmf32_cur.insert(pcmf32_cur.begin(), 3*WHISPER_SAMPLE_RATE, 0.0f);
@@ -198,18 +190,15 @@ void Chess::run() {
                         set_status(txt);
                     }
                     if (!command.empty()) {
-                        set_moves(m_board.processTranscription(command));
+                        set_moves(m_board->processTranscription(command));
                     }
-
                 }
-
-
             }
         }
     }
 }
 
-std::string Chess::transcribe(
+std::string WChess::transcribe(
                 const std::vector<float> & pcmf32,
                 float & logprob_min,
                 float & logprob_sum,
@@ -223,7 +212,7 @@ std::string Chess::transcribe(
     t_ms = 0;
 
     if (whisper_full(m_ctx, m_wparams, pcmf32.data(), pcmf32.size()) != 0) {
-        return "";
+        return {};
     }
 
     std::string result;
diff --git a/examples/wchess/libwchess/WChess.h b/examples/wchess/libwchess/WChess.h
index f97980e8..fd019594 100644
--- a/examples/wchess/libwchess/WChess.h
+++ b/examples/wchess/libwchess/WChess.h
@@ -1,39 +1,59 @@
 #pragma once
-#include "Chessboard.h"
 #include "whisper.h"
 #include <string>
 #include <vector>
+#include <memory>
 
-class Chess {
+class Chessboard;
+
+class WChess {
 public:
-    using StatusSetter = void (*)(const std::string & status);
-    using ISRunning = bool (*)();
-    using AudioGetter = void (*)(int, std::vector<float>&);
-    using MovesSetter = void (*)(const std::string & moves);
-    Chess(  whisper_context * ctx,
-            const whisper_full_params & wparams,
-            StatusSetter status_setter,
-            ISRunning running,
-            AudioGetter audio,
-            MovesSetter moveSetter);
+    using SetStatusCb = void (*)(const std::string &);
+    using CheckRunningCb = bool (*)();
+    using GetAudioCb = void (*)(int, std::vector<float> &);
+    using SetMovesCb = void (*)(const std::string &);
+
+    struct callbacks {
+        SetStatusCb set_status = nullptr;
+        CheckRunningCb check_running = nullptr;
+        GetAudioCb get_audio = nullptr;
+        SetMovesCb set_moves = nullptr;
+    };
+
+    struct settings {
+        int32_t vad_ms     = 2000;
+        int32_t prompt_ms  = 5000;
+        int32_t command_ms = 4000;
+        float vad_thold    = 0.1f;
+        float freq_thold   = -1.0f;
+        bool print_energy  = false;
+    };
+
+    WChess(
+        whisper_context * ctx,
+        const whisper_full_params & wparams,
+        callbacks cb,
+        settings s
+    );
+    ~WChess();
+
     void run();
-    std::string stringifyBoard();
+    std::string stringify_board() const;
 private:
-    void get_audio(int ms, std::vector<float>& pcmf32);
-    void set_status(const char* msg);
-    void set_moves(const std::string& moves);
-    bool check_running();
+    void get_audio(int ms, std::vector<float>& pcmf32) const;
+    void set_status(const std::string& msg) const;
+    void set_moves(const std::string& moves) const;
+    bool check_running() const;
     std::string transcribe(
                     const std::vector<float> & pcmf32,
                     float & logprob_min,
                     float & logprob_sum,
                     int & n_tokens,
                     int64_t & t_ms);
+
     whisper_context * m_ctx;
     whisper_full_params m_wparams;
-    StatusSetter m_status_setter;
-    ISRunning m_running;
-    AudioGetter m_audio;
-    MovesSetter m_moveSetter;
-    Chessboard m_board;
+    const callbacks m_cb;
+    const settings m_settings;
+    std::unique_ptr<Chessboard> m_board;
 };
diff --git a/examples/wchess/wchess.cmd/CMakeLists.txt b/examples/wchess/wchess.cmd/CMakeLists.txt
index 4cd93ac2..a976d93f 100644
--- a/examples/wchess/wchess.cmd/CMakeLists.txt
+++ b/examples/wchess/wchess.cmd/CMakeLists.txt
@@ -4,5 +4,5 @@ if (WHISPER_SDL2)
 
     include(DefaultTargetOptions)
 
-    target_link_libraries(${TARGET} PRIVATE libwchess common common-sdl ${CMAKE_THREAD_LIBS_INIT})
+    target_link_libraries(${TARGET} PRIVATE libwchess common-sdl ${CMAKE_THREAD_LIBS_INIT})
 endif ()
\ No newline at end of file
diff --git a/examples/wchess/wchess.cmd/wchess.cmd.cpp b/examples/wchess/wchess.cmd/wchess.cmd.cpp
index 32e126a8..b3b30023 100644
--- a/examples/wchess/wchess.cmd/wchess.cmd.cpp
+++ b/examples/wchess/wchess.cmd/wchess.cmd.cpp
@@ -1,30 +1,15 @@
-// Voice assistant example
+// Command line voice assisted chess
 //
-// Speak short text commands to the microphone.
-// This program will detect your voice command and convert them to text.
+// Speak chess move commands to the microphone.
+// The moves will translated to chessboard positions.
 //
-// ref: https://github.com/ggerganov/whisper.cpp/issues/171
 //
 
-#include "common-sdl.h"
-#include "common.h"
 #include "WChess.h"
+#include "common-sdl.h"
 
-#include <sstream>
-#include <cassert>
-#include <cstdio>
-#include <fstream>
-#include <mutex>
-#include <regex>
-#include <string>
+#include <memory>
 #include <thread>
-#include <vector>
-#include <map>
-
-bool file_exists(const std::string & fname) {
-    std::ifstream f(fname.c_str());
-    return f.good();
-}
 
 // command-line parameters
 struct whisper_params {
@@ -81,7 +66,6 @@ void whisper_print_usage(int /*argc*/, char ** argv, const whisper_params & para
     fprintf(stderr, "  -cmd FNAME, --commands FNAME [%-7s] text file with allowed commands\n",             params.commands.c_str());
     fprintf(stderr, "  -p,         --prompt         [%-7s] the required activation prompt\n",              params.prompt.c_str());
     fprintf(stderr, "  -ctx,       --context        [%-7s] sample text to help the transcription\n",       params.context.c_str());
-    fprintf(stderr, "  --grammar GRAMMAR            [%-7s] GBNF grammar to guide decoding\n",              params.grammar.c_str());
     fprintf(stderr, "  --grammar-penalty N          [%-7.1f] scales down logits of nongrammar tokens\n",   params.grammar_penalty);
     fprintf(stderr, "\n");
 }
@@ -124,10 +108,9 @@ bool whisper_params_parse(int argc, char ** argv, whisper_params & params) {
     return true;
 }
 
-
-std::unique_ptr<Chess> g_chess;
-void set_moves(const std::string & /* moves */) {
-    fprintf(stdout, "%s", g_chess->stringifyBoard().c_str());
+std::unique_ptr<WChess> g_wchess;
+void set_moves(const std::string & moves) {
+    if (!moves.empty()) fprintf(stdout, "%s", g_wchess->stringify_board().c_str());
 }
 
 audio_async g_audio(30*1000);
@@ -135,10 +118,6 @@ void get_audio(int ms, std::vector<float> & pcmf32_cur) {
     g_audio.get(ms, pcmf32_cur);
 }
 
-bool check_running() {
-    return sdl_poll_events();
-}
-
 int main(int argc, char ** argv) {
     whisper_params params;
 
@@ -189,15 +168,30 @@ int main(int argc, char ** argv) {
 
     wparams.beam_search.beam_size = 5;
 
+    wparams.initial_prompt = params.context.data();
+
     g_audio.resume();
 
     // wait for 1 second to avoid any buffered noise
     std::this_thread::sleep_for(std::chrono::milliseconds(1000));
     g_audio.clear();
 
-    g_chess.reset(new Chess(ctx, wparams, nullptr, sdl_poll_events, get_audio, set_moves));
-    set_moves({});
-    g_chess->run();
+    WChess::callbacks cb;
+    cb.check_running = sdl_poll_events;
+    cb.get_audio = get_audio;
+    cb.set_moves = set_moves;
+
+    WChess::settings s;
+    s.vad_ms = 2000;
+    s.prompt_ms = params.prompt_ms;
+    s.command_ms = params.command_ms;
+    s.vad_thold = params.vad_thold;
+    s.freq_thold = params.freq_thold;
+    s.print_energy = params.print_energy;
+
+    g_wchess.reset(new WChess(ctx, wparams, cb, s));
+    set_moves("start");
+    g_wchess->run();
 
     g_audio.pause();
 
diff --git a/examples/wchess/wchess.wasm/index-tmpl.html b/examples/wchess/wchess.wasm/index-tmpl.html
index 90aecbf1..48c1ccdc 100644
--- a/examples/wchess/wchess.wasm/index-tmpl.html
+++ b/examples/wchess/wchess.wasm/index-tmpl.html
@@ -1,7 +1,7 @@
 <!doctype html>
 <html lang="en-us">
     <head>
-        <title>command : Voice assistant example using Whisper + WebAssembly</title>
+        <title>wchess : Voice assistant example using Whisper + WebAssembly</title>
 
         <style>
             #output {
@@ -28,7 +28,7 @@
     </head>
     <body onload="loadWhisper()">
         <div id="main-container">
-            <b>command : Voice assistant example using Whisper + WebAssembly</b>
+            <b>wchess : Voice assistant example using Whisper + WebAssembly</b>
 
             <br><br>
 
@@ -56,6 +56,14 @@
                 -->
             </div>
 
+            <br>
+            <div id="myBoard" style="width: 400px"></div>
+            <script src="js/jquery-3.7.1.min.js"></script>
+            <script src="js/chessboard-1.0.0.min.js"></script>
+            <script>
+                var board = Chessboard('myBoard', 'start')
+            </script>
+
             <br>
 
             <div id="input">
@@ -72,14 +80,6 @@
                 <pre id="state-moves">[The moves will be displayed here]</pre>
             </div>
 
-            <br><br>
-            <div id="myBoard" style="width: 400px"></div>
-            <script src="js/jquery-3.7.1.min.js"></script>
-            <script src="js/chessboard-1.0.0.min.js"></script>
-            <script>
-                var board = Chessboard('myBoard', 'start')
-            </script>
-
             <hr>
 
             Debug output:
diff --git a/examples/wchess/wchess.wasm/wchess.wasm.cpp b/examples/wchess/wchess.wasm/wchess.wasm.cpp
index 856efad6..c83e1ecd 100644
--- a/examples/wchess/wchess.wasm/wchess.wasm.cpp
+++ b/examples/wchess/wchess.wasm/wchess.wasm.cpp
@@ -1,19 +1,8 @@
-#include "ggml.h"
-#include "common.h"
-
-
-#include <emscripten.h>
+#include <WChess.h>
 #include <emscripten/bind.h>
 
-#include <WChess.h>
-
 #include <atomic>
-#include <cmath>
-#include <mutex>
-#include <string>
 #include <thread>
-#include <vector>
-#include <regex>
 
 constexpr int N_THREAD = 8;
 
@@ -59,6 +48,45 @@ bool check_running() {
     return g_running;
 }
 
+void wchess_main(size_t i) {
+    struct whisper_full_params wparams = whisper_full_default_params(whisper_sampling_strategy::WHISPER_SAMPLING_GREEDY);
+
+    wparams.n_threads        = std::min(N_THREAD, (int) std::thread::hardware_concurrency());
+    wparams.offset_ms        = 0;
+    wparams.translate        = false;
+    wparams.no_context       = true;
+    wparams.single_segment   = true;
+    wparams.print_realtime   = false;
+    wparams.print_progress   = false;
+    wparams.print_timestamps = true;
+    wparams.print_special    = false;
+
+    wparams.max_tokens       = 32;
+    // wparams.audio_ctx        = 768; // partial encoder context for better performance
+
+    wparams.temperature     = 0.4f;
+    wparams.temperature_inc = 1.0f;
+    wparams.greedy.best_of  = 1;
+
+    wparams.beam_search.beam_size = 5;
+
+    wparams.language         = "en";
+
+    printf("command: using %d threads\n", wparams.n_threads);
+
+    WChess::callbacks cb;
+    cb.set_status = set_status;
+    cb.check_running = check_running;
+    cb.get_audio = get_audio;
+    cb.set_moves = set_moves;
+
+    WChess(g_contexts[i], wparams, cb, {}).run();
+    if (i < g_contexts.size()) {
+        whisper_free(g_contexts[i]);
+        g_contexts[i] = nullptr;
+    }
+}
+
 EMSCRIPTEN_BINDINGS(command) {
     emscripten::function("init", emscripten::optional_override([](const std::string & path_model) {
         for (size_t i = 0; i < g_contexts.size(); ++i) {
@@ -70,44 +98,7 @@ EMSCRIPTEN_BINDINGS(command) {
                         g_worker.join();
                     }
                     g_worker = std::thread([i]() {
-
-                        struct whisper_full_params wparams = whisper_full_default_params(whisper_sampling_strategy::WHISPER_SAMPLING_GREEDY);
-
-                        wparams.n_threads        = std::min(N_THREAD, (int) std::thread::hardware_concurrency());
-                        wparams.offset_ms        = 0;
-                        wparams.translate        = false;
-                        wparams.no_context       = true;
-                        wparams.single_segment   = true;
-                        wparams.print_realtime   = false;
-                        wparams.print_progress   = false;
-                        wparams.print_timestamps = true;
-                        wparams.print_special    = false;
-
-                        wparams.max_tokens       = 32;
-                        // wparams.audio_ctx        = 768; // partial encoder context for better performance
-
-                        wparams.temperature     = 0.4f;
-                        wparams.temperature_inc = 1.0f;
-                        wparams.greedy.best_of  = 1;
-
-                        wparams.beam_search.beam_size = 5;
-
-                        wparams.language         = "en";
-
-                        printf("command: using %d threads\n", wparams.n_threads);
-
-                        Chess(g_contexts[i],
-                            wparams,
-                            set_status,
-                            check_running,
-                            get_audio,
-                            set_moves).run();
-
-                        if (i < g_contexts.size()) {
-                            whisper_free(g_contexts[i]);
-                            g_contexts[i] = nullptr;
-                        }
-
+                        wchess_main(i);
                     });
 
                     return i + 1;