fix: MCPCをvendored fork化しMCP準拠と接続安定性を改善

- Git submoduleを廃止してMCPCを直接管理
- Windowsで254リクエスト付近に発生する切断を修正
- JSON-RPC 2.0エラー応答を標準化
- tool schemaとruntimeの必須・任意引数を一致
- 1000回連続呼び出しの回帰テストを追加

7 files changed, 40 insertions, 24 deletions

diff --git a/src/mcp/server.c b/src/mcp/server.c
index a0ff436..498e9f4 100644
--- a/src/mcp/server.c
+++ b/src/mcp/server.c
@@ -30,6 +30,10 @@ tiny_convmem_server_run(FILE *input, FILE *output, tiny_store_t *store)
       return 1;
     }
   status = mcpc_server_start(server);
+  if (status != MCPC_EC_0)
+    {
+      fprintf(stderr, "mcpc server stopped with status %d\n", (int)status);
+    }
   tiny_mcp_tools_context_deactivate(context);
   mcpc_server_close(server);
   tiny_mcp_tools_context_free(context);
diff --git a/src/mcp/tools/common/common.c b/src/mcp/tools/common/common.c
index 71b6f68..d6669f8 100644
--- a/src/mcp/tools/common/common.c
+++ b/src/mcp/tools/common/common.c
@@ -104,7 +104,8 @@ bool
 tiny_mcp_tool_add_property(mcpc_tool_t *tool,
                            const char *name,
                            const char *description,
-                           mcpc_anytype_t type)
+                           mcpc_anytype_t type,
+                           bool required)
 {
   mcpc_toolprop_t *property
       = mcpc_toolprop_new2((const char8_t *)name, (const char8_t *)description, type);
@@ -112,6 +113,10 @@ tiny_mcp_tool_add_property(mcpc_tool_t *tool,
     {
       return false;
     }
+  if (mcpc_toolprop_set_required(property, required) != MCPC_EC_0)
+    {
+      return false;
+    }
   mcpc_tool_add_toolprop(tool, property);
   return true;
 }
diff --git a/src/mcp/tools/common/common.h b/src/mcp/tools/common/common.h
index 6b1cc96..07caea1 100644
--- a/src/mcp/tools/common/common.h
+++ b/src/mcp/tools/common/common.h
@@ -14,6 +14,7 @@ mcpc_tool_t *tiny_mcp_tool_new(const char *name, const char *description, mcpc_t
 bool tiny_mcp_tool_add_property(mcpc_tool_t *tool,
                                 const char *name,
                                 const char *description,
-                                mcpc_anytype_t type);
+                                mcpc_anytype_t type,
+                                bool required);
 
 #endif
diff --git a/src/mcp/tools/delete_message.c b/src/mcp/tools/delete_message.c
index ae924d7..8b6e8f9 100644
--- a/src/mcp/tools/delete_message.c
+++ b/src/mcp/tools/delete_message.c
@@ -14,14 +14,15 @@ call_delete_message(const mcpc_tool_t *tool, mcpc_ucbr_t *result)
   char *message_id = tiny_mcp_tool_get_string(tool, "message_id", TINY_MESSAGE_ID_LENGTH);
   char *session = tiny_mcp_tool_get_string(tool, "session_id", TINY_SESSION_ID_MAX);
   tiny_store_status_t status;
-  if (!context || !message_id || !session || !tiny_message_id_valid(message_id))
+  if (!context || !message_id || !tiny_message_id_valid(message_id))
     {
       tiny_mcp_tool_add_error(
           result, "VALIDATION_ERROR", "message_id must be a canonical 26-character ULID");
     }
   else
     {
-      status = tiny_store_delete(context->store, message_id, session[0] ? session : NULL);
+      status
+          = tiny_store_delete(context->store, message_id, session && session[0] ? session : NULL);
       if (status != TINY_STORE_OK && status != TINY_STORE_NOT_FOUND)
         {
           tiny_mcp_tool_add_error(
@@ -43,8 +44,7 @@ bool
 tiny_mcp_register_delete_message(mcpc_server_t *server)
 {
   mcpc_tool_t *tool = tiny_mcp_tool_new("delete_message", "Delete a message", call_delete_message);
-  return tool && tiny_mcp_tool_add_property(tool, "message_id", "Message ULID", MCPC_U8STR)
-         && tiny_mcp_tool_add_property(
-             tool, "session_id", "Session ID; empty if omitted", MCPC_U8STR)
+  return tool && tiny_mcp_tool_add_property(tool, "message_id", "Message ULID", MCPC_U8STR, true)
+         && tiny_mcp_tool_add_property(tool, "session_id", "Optional session ID", MCPC_U8STR, false)
          && mcpc_server_add_tool(server, tool) == MCPC_EC_0;
 }
diff --git a/src/mcp/tools/read_messages.c b/src/mcp/tools/read_messages.c
index 55696d6..5a9e49f 100644
--- a/src/mcp/tools/read_messages.c
+++ b/src/mcp/tools/read_messages.c
@@ -75,6 +75,6 @@ bool
 tiny_mcp_register_read_messages(mcpc_server_t *server)
 {
   mcpc_tool_t *tool = tiny_mcp_tool_new("read_messages", "Read a session", call_read_messages);
-  return tool && tiny_mcp_tool_add_property(tool, "session_id", "Session ID", MCPC_U8STR)
+  return tool && tiny_mcp_tool_add_property(tool, "session_id", "Session ID", MCPC_U8STR, true)
          && mcpc_server_add_tool(server, tool) == MCPC_EC_0;
 }
diff --git a/src/mcp/tools/search_messages.c b/src/mcp/tools/search_messages.c
index 166c167..d20d7b2 100644
--- a/src/mcp/tools/search_messages.c
+++ b/src/mcp/tools/search_messages.c
@@ -45,14 +45,15 @@ call_search_messages(const mcpc_tool_t *tool, mcpc_ucbr_t *result)
   tiny_mcp_tools_context_t *context = tiny_mcp_tools_context_current();
   char *query = tiny_mcp_tool_get_string(tool, "query", TINY_QUERY_MAX);
   char *session = tiny_mcp_tool_get_string(tool, "session_id", TINY_SESSION_ID_MAX);
-  int32_t requested_limit = 0;
+  int32_t requested_limit = 20;
+  mcpc_errcode_t limit_status
+      = mcpc_tool_get_tpropval_i32(tool, (const char8_t *)"limit", &requested_limit);
   size_t limit, index, count = 0, candidate_count = 0, *candidates = NULL;
   result_item_t *items = NULL;
   tiny_json_buffer_t json;
-  bool valid
-      = context && query && query[0] && session
-        && mcpc_tool_get_tpropval_i32(tool, (const char8_t *)"limit", &requested_limit) == MCPC_EC_0
-        && requested_limit >= 1 && requested_limit <= 100;
+  bool valid = context && query && query[0]
+               && (limit_status == MCPC_EC_0 || limit_status == MCPC_EC_ANYDATA_NOTFOUND)
+               && requested_limit >= 1 && requested_limit <= 100;
   if (!valid)
     {
       tiny_mcp_tool_add_error(result, "VALIDATION_ERROR", "query or limit is invalid");
@@ -85,7 +86,7 @@ call_search_messages(const mcpc_tool_t *tool, mcpc_ucbr_t *result)
                       = tiny_store_entry(context->store, candidates[index]);
                   double score;
                   if (!entry || entry->deleted
-                      || (session[0] && strcmp(entry->message.session_id, session) != 0))
+                      || (session && session[0] && strcmp(entry->message.session_id, session) != 0))
                     {
                       continue;
                     }
@@ -127,8 +128,10 @@ bool
 tiny_mcp_register_search_messages(mcpc_server_t *server)
 {
   mcpc_tool_t *tool = tiny_mcp_tool_new("search_messages", "Search messages", call_search_messages);
-  return tool && tiny_mcp_tool_add_property(tool, "query", "Search text", MCPC_U8STR)
-         && tiny_mcp_tool_add_property(tool, "session_id", "Session ID; empty for all", MCPC_U8STR)
-         && tiny_mcp_tool_add_property(tool, "limit", "Result limit from 1 to 100", MCPC_I32)
+  return tool && tiny_mcp_tool_add_property(tool, "query", "Search text", MCPC_U8STR, true)
+         && tiny_mcp_tool_add_property(
+             tool, "session_id", "Optional session ID; omitted searches all", MCPC_U8STR, false)
+         && tiny_mcp_tool_add_property(
+             tool, "limit", "Optional result limit from 1 to 100; defaults to 20", MCPC_I32, false)
          && mcpc_server_add_tool(server, tool) == MCPC_EC_0;
 }
diff --git a/src/mcp/tools/write_message.c b/src/mcp/tools/write_message.c
index 1d7ece2..f9c078a 100644
--- a/src/mcp/tools/write_message.c
+++ b/src/mcp/tools/write_message.c
@@ -162,8 +162,8 @@ call_write_message(const mcpc_tool_t *tool, mcpc_ucbr_t *result)
   input.content = tiny_mcp_tool_get_string(tool, "content", TINY_CONTENT_MAX);
   metadata = tiny_mcp_tool_get_string(tool, "metadata_json", TINY_CONTENT_MAX);
   bool valid = context && input.session_id && input.session_id[0] && role && input.content
-               && input.content[0] && metadata && tiny_role_parse(role, &input.role)
-               && parse_metadata(metadata, &input);
+               && input.content[0] && tiny_role_parse(role, &input.role)
+               && parse_metadata(metadata ? metadata : "{}", &input);
   if (!valid)
     {
       tiny_mcp_tool_add_error(result, "VALIDATION_ERROR", "invalid write_message arguments");
@@ -204,10 +204,13 @@ tiny_mcp_register_write_message(mcpc_server_t *server)
 {
   mcpc_tool_t *tool
       = tiny_mcp_tool_new("write_message", "Append a conversation message", call_write_message);
-  return tool && tiny_mcp_tool_add_property(tool, "session_id", "Session ID", MCPC_U8STR)
-         && tiny_mcp_tool_add_property(tool, "role", "user, assistant, or system", MCPC_U8STR)
-         && tiny_mcp_tool_add_property(tool, "content", "Message text", MCPC_U8STR)
-         && tiny_mcp_tool_add_property(
-             tool, "metadata_json", "Metadata object JSON; use {} when empty", MCPC_U8STR)
+  return tool && tiny_mcp_tool_add_property(tool, "session_id", "Session ID", MCPC_U8STR, true)
+         && tiny_mcp_tool_add_property(tool, "role", "user, assistant, or system", MCPC_U8STR, true)
+         && tiny_mcp_tool_add_property(tool, "content", "Message text", MCPC_U8STR, true)
+         && tiny_mcp_tool_add_property(tool,
+                                       "metadata_json",
+                                       "Optional metadata object JSON; defaults to {}",
+                                       MCPC_U8STR,
+                                       false)
          && mcpc_server_add_tool(server, tool) == MCPC_EC_0;
 }