memory_map

Persistent memory and conversation history MCP server for Claude Code — key-value context store, rolling history, and cross-project recall across sessions.

When to Activate

• Installing memory_map for the first time or on a new machine
• Writing CLAUDE.md session-setup instructions (load_memory, load_history)
• Deciding what belongs in memory vs history vs inline code comments
• Using cross-project or global memory tools
• Configuring history compression or external summarization
• Debugging why Claude starts a session without prior context
• Manually checkpointing conversation history with /mem_save

Architecture

memory_map/
├── server.py          — MCP server (stdio transport)
├── history_hook.py    — hook script: saves history on UserPromptSubmit / Stop / PreCompact
├── CLAUDE.md          — copy into any project to enable session-start loading
└── venv/              — Python virtualenv

Per-project files (written to the project root automatically):
├── .mcp_memory.json   — key-value store (load_memory / save_memory)
└── .mcp_history.json  — rolling conversation history (20 chunks)

MCP registration makes all tools available globally. Per-project activation is controlled by CLAUDE.md — Claude only calls load_memory / load_history automatically if the instructions tell it to.

Installation

Step 1 — Clone and Install

git clone https://github.com/kid-sid/memory_map.git
cd memory_map

# Windows
python -m venv venv
venv\Scripts\pip install -r requirements.txt

# Mac/Linux
python3 -m venv venv
source venv/bin/activate && pip install -r requirements.txt

Step 2 — Register the MCP Server

# Global — available in every project (recommended)
# Windows
claude mcp add -s user memory_map \
  C:/Users/yourname/memory_map/venv/Scripts/python.exe \
  C:/Users/yourname/memory_map/server.py

# Mac/Linux
claude mcp add -s user memory_map \
  python3 /home/yourname/memory_map/server.py

Registration scope options:

Scope flag	Stored in	Available
-s user	~/.claude/mcp.json	All projects on this machine
-s project	.claude/mcp.json	This repo only (committed, shared)
-s local	.claude/mcp.local.json	This repo only (gitignored, personal)

Always use -s user for memory_map — it stores files with local paths that differ per machine.

Verify: claude mcp list → should show memory_map.

Step 3 — Lifecycle Hooks

Add to ~/.claude/settings.json so history is captured automatically in every project:

{
  "hooks": {
    "UserPromptSubmit": [
      {
        "matcher": "",
        "hooks": [{
          "type": "command",
          "command": "python C:/Users/yourname/memory_map/history_hook.py",
          "timeout": 10
        }]
      }
    ],
    "PreCompact": [
      {
        "matcher": "",
        "hooks": [{
          "type": "command",
          "command": "python C:/Users/yourname/memory_map/history_hook.py --force",
          "timeout": 15
        }]
      }
    ],
    "Stop": [
      {
        "matcher": "",
        "hooks": [{
          "type": "command",
          "command": "python C:/Users/yourname/memory_map/history_hook.py --force",
          "timeout": 15,
          "async": true
        }]
      }
    ]
  }
}

Mac/Linux: use python3 and POSIX paths.

Hook	When	Flag
UserPromptSubmit	Every message — incremental saves	none
PreCompact	Before context window compaction	--force
Stop	When Claude finishes a turn	--force, async: true

Step 4 — Enable Per-Project Memory

Copy CLAUDE.md from the memory_map repo into the project root:

# Windows
copy C:\Users\yourname\memory_map\CLAUDE.md CLAUDE.md

# Mac/Linux
cp ~/memory_map/CLAUDE.md ~/your-project/CLAUDE.md

Commit CLAUDE.md — teammates get session-start loading automatically. The file content Claude needs:

## Session Setup (Required)
At the start of every session, before doing anything else:
1. Call `load_memory` with the current working directory
2. Call `load_history` with the current working directory
3. Read both outputs before exploring files or asking questions

---

Memory Tools

save_memory / load_memory / delete_memory

Per-project key-value store. Values persist in .mcp_memory.json.

save_memory(project_path, key, value)
load_memory(project_path)         → returns all key-value pairs
delete_memory(project_path, key)

Key conventions:

Key	What to store
stack	Language, framework, runtime versions
current_work	Active feature, bug, or initiative
gotchas	Non-obvious constraints, known failures, env quirks
key_files	Entry points, config files, critical paths
conventions	Non-obvious team decisions not in the code
blockers	Current blockers or dependencies on others

Rules:

• Short, lowercase, underscore-separated keys
• Values: one or two sentences max — dense, not verbose
• Overwrite stale values with the same key; don't accumulate duplicates
• Convert relative dates to absolute: "Thursday" → "2026-05-15"

What NOT to save in memory:

• Code patterns and architecture (read the code)
• Git history / who changed what (git log / git blame)
• Fix recipes (the fix is in the code; commit message has context)
• Ephemeral task state (in-progress work, current conversation)
• Anything already in CLAUDE.md

Global Memory

Shared across all projects on the machine:

save_global_memory(key, value)
load_global_memory()

Use for: user identity, preferred tools, cross-project conventions, API key locations (not values). Never store secrets.

---

History Tools

load_history / save_history

Rolling conversation history stored in .mcp_history.json (20 chunks max). history_hook.py calls save_history automatically via hooks — no manual calls needed during normal use.

load_history(project_path, last_n=5)   → returns N most recent chunks
save_history(project_path, content)

Manual Checkpoint: /mem_save

Run /mem_save at any time to force-save the current conversation as a history chunk. Use before long operations, context compaction, or ending a session mid-task.

---

Cross-Project Tools

Tool	What it does
list_projects	List all projects that have saved memory
get_project_summary(project_path)	One-line summary of a project's memory
load_cross_project_memory(project_path)	Load memory from a different project
search_across_projects(query)	Full-text search across all project memories

Use cases:

• Referencing a pattern from a sibling project
• Finding which project owns a shared library
• Onboarding to a new project by comparing to a known one

---

Utility Tools

Tool	What it does
get_local_structure(project_path)	Gitignore-aware directory tree
get_github_structure(owner, repo, branch?)	GitHub repo file tree via API
get_git_history(project_path, limit?)	Recent commits

These are read-only exploration tools — call them at session start to orient quickly without reading every file.

---

Compression

set_compression(project_path, level)

Level	Output	When to use
0	Raw — full fidelity	Debugging, inspecting history content
1	Compact — whitespace stripped	Normal use
2	Dense — abbreviations, no filler	Low context budget, large histories

Set per-project; persists until changed. Default is compact (1).

---

Privacy and External Summarization

History is stored locally by default using simple truncation — no data leaves the machine.

To enable OpenAI-backed summarization (richer history compression):

# Add to your environment / shell profile
export OPENAI_API_KEY="sk-..."
export MCP_HISTORY_EXTERNAL_SUMMARIZE=1

When both are set, history_hook.py sends up to 4 000 characters of recent conversation to gpt-4o-mini before storing the summary locally.

What gets sent: recent dialogue including source code, file contents, and environment details. Only enable if you're comfortable with that leaving your machine. Do not enable on machines with proprietary codebases unless your org has approved the OpenAI data-processing agreement.

---

CLAUDE.md Session-Start Pattern

Minimal session-setup block for any project:

## Session Setup (Required)
At the start of every session, before doing anything else:
1. Call `load_memory` with the current working directory
2. Call `load_history` with the current working directory
3. Read both outputs before exploring files or asking questions

Save or update memory entries whenever you learn something worth keeping across sessions.
If something loaded from memory is no longer accurate, update it with `save_memory` using the same key.
Use short, lowercase keys: `stack`, `current_work`, `gotchas`, `key_files`. Keep values concise.

Extend this block with project-specific keys or additional tool calls (get_local_structure, etc.) when the project benefits from them.

---

Troubleshooting

Symptom	Likely cause	Fix
Claude starts sessions cold with no memory	CLAUDE.md missing or not instructing load_memory	Copy CLAUDE.md from memory_map repo into project root
load_memory returns "no memory saved yet"	First session, or memory was deleted	Normal — save entries as context is established
History not saving between sessions	Hooks missing or wrong path in settings.json	Verify history_hook.py path; run it manually: python memory_map/history_hook.py --force
MCP server not found	Not registered, or wrong Python path	Re-run claude mcp add; verify with claude mcp list
history_hook.py hangs the session	No timeout on hook or slow Python startup	Ensure "timeout": 10 is set; use virtualenv Python, not system Python
Memory values growing stale	Not updating keys after project shifts	Always overwrite with the same key rather than adding new ones

---

Red Flags

• Putting API keys or passwords in save_memory — memory is stored in .mcp_memory.json in the project root, which may be committed or shared; store only key names and env var references, never values
• No CLAUDE.md after registering the MCP server — registration makes tools available but doesn't call them; Claude only auto-loads memory if the session-setup instructions tell it to
• Using -s project for memory_map registration — project-scoped MCP servers are committed and affect all teammates, but memory_map stores files at local absolute paths that differ per machine; use -s user always
• Saving entire file contents or code blocks in memory — memory values should be one to two sentences; large values bloat .mcp_memory.json, slow load times, and crowd out useful keys
• Setting MCP_HISTORY_EXTERNAL_SUMMARIZE=1 on a machine with proprietary code — history includes file contents; check your org's data policy before enabling OpenAI-backed summarization
• Hooks without timeout — a stalled history_hook.py (e.g., network timeout during OpenAI summarization) blocks Claude Code indefinitely; always set "timeout": N
• Calling load_history + get_history_chunks manually at session start — these are for inspection and the /mem_save flow only; use load_history(last_n=5) for session continuity, not the raw chunk API

---

Checklist

• memory_map cloned; virtualenv created; pip install -r requirements.txt succeeded
• claude mcp list shows memory_map with correct Python path
• Registration used -s user (not -s project or -s local)
• Three lifecycle hooks present in ~/.claude/settings.json: UserPromptSubmit, PreCompact, Stop
• Every hook has a "timeout" value; Stop hook has "async": true
• CLAUDE.md copied into the project root and committed
• CLAUDE.md instructs load_memory and load_history at session start
• No secrets stored in save_memory — only descriptive values and env var names
• Memory keys are short, lowercase, and overwrite stale values (no duplicates)
• Compression level set appropriately for the project's history volume
• External summarization (MCP_HISTORY_EXTERNAL_SUMMARIZE=1) only enabled after data-policy check
• /mem_save used before context compaction or ending a long session mid-task