Ready to use build: https://yadi.sk/d/ZHvALFzz3JTXAF

Portal2AutoPause.cpp

#define WIN32_LEAN_AND_MEAN
#include <Windows.h>
#include <process.h>
#include <Psapi.h>

#include <cstdint>
#include <cstring>
#include <string>
using std::uint8_t;
using std::size_t;
using std::uintptr_t;
using namespace std::literals;

#include <MinHook.h>

struct module_info
{
	HMODULE handle;
	LPVOID base;
	DWORD size;
};

struct pattern
{
	const uint8_t* bytes;
	const char* mask;
};

constexpr uint8_t bytes_SetSignonState[] = { 0x55, 0x8B, 0xEC, 0x56, 0x57, 0x8B, 0x7D, 0x08, 0x8B, 0xF1, 0x83, 0xFF, 0x02, 0x75, 0x71, 0x8B, 0x46, 0x04, 0x8B, 0x90, 0xA0, 0x00, 0x00, 0x00, 0x8D, 0x4E, 0x04, 0xFF, 0xD2, 0x84, 0xC0, 0x75 };
constexpr pattern pattern_SetSignonState = {
	bytes_SetSignonState,
	"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
};

constexpr uint8_t bytes_SomeDemoFunction[] = { 0x55, 0x8B, 0xEC, 0x8B, 0x45, 0x08, 0x81, 0xEC, 0x0C, 0x02, 0x00, 0x00, 0x56, 0x8B, 0xF1, 0x85, 0xC0, 0x0F, 0x84, 0xAA, 0x00, 0x00, 0x00, 0x80, 0x38, 0x00, 0x0F, 0x84, 0xA1, 0x00, 0x00, 0x00 };
constexpr pattern pattern_SomeDemoFunction = {
	bytes_SomeDemoFunction,
	"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
};

static module_info get_module_info(LPCWSTR name)
{
	module_info rv;

	rv.handle = GetModuleHandleW(name);
	if (rv.handle) {
		MODULEINFO info;
		if (GetModuleInformation(GetCurrentProcess(), rv.handle, &info, sizeof(info))) {
			rv.base = info.lpBaseOfDll;
			rv.size = info.SizeOfImage;
		}
	}

	return rv;
}

static bool compare(const uint8_t* data, const pattern& pattern)
{
	auto bytes = pattern.bytes;
	auto mask = pattern.mask;
	for (; *mask != '\0'; ++data, ++bytes, ++mask)
		if (*mask == 'x' && *data != *bytes)
			return false;

	return true;
}

static uintptr_t find_pattern(const module_info& module, const pattern& pattern)
{
	auto length = std::strlen(pattern.mask);
	auto p = reinterpret_cast<const uint8_t*>(module.base);
	auto end = p + module.size - length;

	for (; p <= end; ++p)
		if (compare(p, pattern))
			return reinterpret_cast<uintptr_t>(p);

	return 0;
}

namespace engine_dll
{
	using SetSignonState_t = bool (__fastcall *)(void* thisptr, int edx, int state, int spawncount);
	SetSignonState_t SetSignonState;
	using Cbuf_GetCommandBuffer_t = void* (__cdecl *)();
	Cbuf_GetCommandBuffer_t Cbuf_GetCommandBuffer;
	using Cbuf_AddText_t = void (__cdecl *)(void* command_buffer, const char* text, int unknown);
	Cbuf_AddText_t Cbuf_AddText;

	static bool __fastcall MySetSignonState(void* thisptr, int edx, int state, int spawncount)
	{
		constexpr int SIGNONSTATE_FULL = 6;
		if (state == SIGNONSTATE_FULL) {
			//MessageBoxW(0, L"SetSignonState(SIGNONSTATE_FULL)", L"Portal2AutoPause", MB_ICONINFORMATION);
			Cbuf_AddText(Cbuf_GetCommandBuffer(), "toggleconsole\n", 0);
		}

		auto rv = SetSignonState(thisptr, edx, state, spawncount);


		return rv;
	}
}

static unsigned __stdcall main_thread(void* args)
{
	auto engine = get_module_info(L"engine.dll");
	if (!engine.handle) {
		MessageBoxW(0, L"Could not get engine.dll module info.", L"Portal2AutoPause", MB_ICONERROR);
		return 1;
	}

	auto SetSignonState = find_pattern(engine, pattern_SetSignonState);
	if (!SetSignonState) {
		MessageBoxW(0, L"Could not find CBaseClient::SetSignonState.", L"Portal2AutoPause", MB_ICONERROR);
		return 1;
	}

	auto SomeDemoFunction = find_pattern(engine, pattern_SomeDemoFunction);
	if (!SomeDemoFunction) {
		MessageBoxW(0, L"Could not find the Cbuf pattern.", L"Portal2AutoPause", MB_ICONERROR);
		return 1;
	}

	engine_dll::Cbuf_GetCommandBuffer = reinterpret_cast<engine_dll::Cbuf_GetCommandBuffer_t>(*reinterpret_cast<uintptr_t*>(SomeDemoFunction + 121) + SomeDemoFunction + 125);
	engine_dll::Cbuf_AddText = reinterpret_cast<engine_dll::Cbuf_AddText_t>(*reinterpret_cast<uintptr_t*>(SomeDemoFunction + 127) + SomeDemoFunction + 131);

	auto err = MH_Initialize();
	if (err != MH_OK) {
		MessageBoxA(0, ("MH_Initialize error: "s + MH_StatusToString(err)).c_str(), "Portal2AutoPause", MB_ICONERROR);
		return 1;
	}
	err = MH_CreateHook(reinterpret_cast<LPVOID>(SetSignonState), engine_dll::MySetSignonState, reinterpret_cast<LPVOID*>(&engine_dll::SetSignonState));
	if (err != MH_OK) {
		MessageBoxA(0, ("MH_CreateHook error: "s + MH_StatusToString(err)).c_str(), "Portal2AutoPause", MB_ICONERROR);
		return 1;
	}
	err = MH_EnableHook(reinterpret_cast<LPVOID>(SetSignonState));
	if (err != MH_OK) {
		MessageBoxA(0, ("MH_EnableHook error: "s + MH_StatusToString(err)).c_str(), "Portal2AutoPause", MB_ICONERROR);
		return 1;
	}

	return 0;
}

BOOL APIENTRY DllMain(HMODULE module, DWORD reason, LPVOID reserved)
{
	switch (reason) {
	case DLL_PROCESS_ATTACH:
		DisableThreadLibraryCalls(module);
		_beginthreadex(nullptr, 0, main_thread, nullptr, 0, nullptr);
		break;

	case DLL_PROCESS_DETACH:
		break;
	}

	return TRUE;
}

When is TAS ?
(Just kidding don't do it)

Is Autojump and/or ABH even possible at all?

when is autojump

is this legal?