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

1 files changed, 10 insertions, 7 deletions

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;
 }