claude-mem vs Hopper

claude-mem is an open-source memory compression plugin that gives Claude Code a persistent brain across sessions. It hooks into six Claude Code lifecycle events to automatically capture tool observations, compress them into semantic summaries, and store everything in a local SQLite + Chroma vector database. When a new session starts, relevant context is injected automatically — no copy-pasting, no re-explaining architecture decisions you made last week. The system achieves roughly a 10x token reduction through progressive disclosure: it retrieves only what's relevant for the current task rather than dumping everything into context. Developers can query their memory store via natural language through MCP tools (search, timeline, get_observations), and a built-in web viewer at localhost:37777 lets you inspect memory streams visually. Privacy controls via <private> tags let you keep sensitive content out of the store. Install is a single npx command, and it works with Claude Code, Gemini CLI, and OpenClaw gateways. The project hit 48K+ GitHub stars and is clearly scratching a real itch: the loss of context between sessions is one of the most consistent pain points for AI-assisted development.

Hopper, from YC S24 startup Hypercubic, is the first agentic development environment purpose-built for mainframe systems. It lets AI agents navigate TN3270 terminals autonomously, write and submit JCL jobs, monitor JES output, debug failed jobs by analyzing spool data, query VSAM datasets, compile and run COBOL code, and manage CICS transactions—all via natural language prompts. Tasks that traditionally took mainframe specialists hours of manual TN3270 navigation can now be expressed as a single instruction. The technical challenge here is real: mainframes don't have nice REST APIs or modern dev tooling. They run on green-screen terminal protocols from the 1970s, and the humans who know how to operate them are retiring faster than they can be replaced. Hopper essentially wraps the entire mainframe interaction surface in an agent-friendly interface, translating intent into the arcane sequences of keystrokes and JCL that mainframes actually require. The product is free for individual developers (all core features, macOS/Windows/Linux) with Enterprise pricing for SSO, on-prem deployment, and SOC 2 reports. Hypercubic's team includes alumni from Cognition, Apple, and Windsurf. Given that mainframes still process an estimated $3 trillion in daily commerce and the COBOL developer shortage is acute, Hopper is targeting a genuinely underserved market with unusual urgency.