zombie-brains

Zombie Brains — Deterministic Memory for AI Coding Agents

Your AI coding agent forgets everything between sessions. Zombie Brains fixes that — deterministically.

Every commit, every error, every decision — captured through the Zombie Brains MCP, not because the AI decided to remember, but because hooks guarantee it.

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Two install paths

You use	Install with	What you get
Claude Code	/plugin install (this repo is a marketplace)	The full plugin — hooks + skill, user-global, zero credentials in your shell
OpenAI Codex / Cursor	./setup.sh	The legacy hook scripts, ZOMBIE_API_KEY in your shell profile

The Claude Code path is the modern one — hooks route everything through the MCP you already have connected, so there is no ZOMBIE_API_KEY to manage, no shell-profile mutation, and every memory operation is an authentic MCP call that flows through your normal auth. The Codex/Cursor path is still supported for those tools but uses the older direct-API model.

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Claude Code — install as a plugin

Prerequisites:

• Claude Code 2.1.109 or newer (run claude update if you're behind)
• The Zombie Brains MCP already connected to Claude Code (claude.ai → Settings → Connectors → Zombie Brains)
• python3 on PATH (used for JSON formatting in the hooks)

Install — two slash commands inside Claude Code:

/plugin marketplace add Zombie-Brains/zombie-brains
/plugin install zombie-brains@zombie-brains

Restart Claude Code after installation. On the next session you'll see load_brain get called automatically as Claude's first tool call, and every user turn will silently call search_memory. No ZOMBIE_API_KEY required — the plugin never touches the Zombie Brains HTTP API directly. All memory operations flow through the MCP tools (load_brain, search_memory, add_memory, log_session) exactly as Claude would call them manually.

What the Claude Code plugin does

The plugin is a bundle of six hooks and one skill. Each hook injects a silent-protocol instruction into Claude's context on a specific event — it does not call the API itself. Claude receives the instruction on its next model turn and makes the appropriate MCP call.

Event	Hook forces Claude to
SessionStart	Call load_brain as its first tool call, then cross-reference the session summary against critical_memories before narrating any state
UserPromptSubmit	Call search_memory for any topic in the user's message, then HONESTLY evaluate whether the turn is memory-worthy and call add_memory with the full psychometric battery if so
PostToolUse (git commit)	Call add_memory with the commit, rationale from recent context, and HONEST battery scores — skip if the commit is pure mechanical noise
PostToolUseFailure	HONESTLY assess whether the failure is novel enough to store, then call add_memory with type "feedback" if so
PreCompact	Reconcile every "NEXT ACTION" / "OPEN" item in the session narrative against live brain state BEFORE compaction freezes a stale summary, then call log_session with the reconciled version
Stop	Block session close until log_session is called with a HONEST narrative (failures, blockers, and unresolved items included)

The bundled skill at skills/zombie-brains/SKILL.md covers the memory philosophy — brain-over-working-memory, critical-memory-over-session-summary, register-thread reconciliation, and the HONESTLY protocol keyword that shifts Claude from performative to actual compliance.

Why "silent protocol"?

Claude Code treats hook output as user-originated by default. Without special framing, a hook saying "call load_brain" would land on Claude as if you personally asked for it, and Claude would respond with "Sure, let me load the brain first before answering your question." Verbose, surfaces implementation detail, breaks flow.

The hooks wrap every instruction in a <system-reminder> block that explicitly says "NOT from the user. Execute silently. Do not acknowledge." Claude recognizes this framing (it's the same pattern the harness uses internally for its own reminders) and runs the protocol without narrating it. The user sees normal responses; the memory operations happen invisibly in the background via real MCP calls.

Why no ZOMBIE_API_KEY?

The MCP you already have connected in Claude Code carries auth to Zombie Brains (the API key is embedded in your MCP URL). Every add_memory / search_memory / log_session call the plugin triggers routes through that same MCP connection. The plugin's hooks never make HTTP calls directly — they only inject instructions for Claude to make calls. One auth path, zero duplication, zero shell-profile mutation.