Context Engine/MCP

Hi everyone. I have been using opus 4.5 with Augment Code, I also tried it with AMP too. These are insnaely good, but I got to a point where I was spending $150+ per day because they do not allow you to use your own Claude Code subscription. Are there any good context engines/plugins that people are using? I'm finding opus 4.5 isn't that great on it's own when you're running much larger projects. I'm looking for a solution that can take prompts, split into tasks and index the entire code base just like Augment does TIA