# Mneme Decision MCP

A local stdio MCP server for project architecture decisions and ADRs. It gives coding agents context on engineering standards while keeping approval authority strictly human.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI · ★ 28
- Author: MnemeHQ
- License: MIT · policy=link-only · description only; the file stays with the author
- Source: https://github.com/MnemeHQ/mneme
- Updated: 2026-10-24
- HTML: https://affpapa.org/en/nevibecode/mcp/mneme-decision-mcp

## What it does

Mneme Decision MCP connects coding agents to the decision index stored in `.mneme/project_memory.json`. Agents query established design choices before editing files and verify compliance against recorded standards. Python 3.11+ is required.

The server surface contains exactly six tools: `decision.propose`, `decision.propose_batch`, `decision.get`, `decision.search`, `decision.applicable_to`, and `decision.trace`. The agent can submit candidate proposals or look up previous choices. Crucially, the server exposes zero tools for accepting, superseding, or bypassing decisions, keeping final governance entirely in human hands via the CLI.

Startup fails closed if `.mneme/project_memory.json` lacks an authoritative `decision_index` block. In that case, you must run `mneme decision-index migrate` before the server will answer queries.

## Requirements
- Needs: Python and uv (commands run via uvx)

## Install

### Claude Code (native platform)

**Platform CLI**
```bash
claude mcp add mneme -- uvx mneme-hq
```
uvx runs the command named after the package; if the README names another one, use uvx --from mneme-hq <command>

### Codex

**Platform CLI**
```bash
codex mcp add mneme-decision-mcp -- uvx mneme-hq
```
uvx runs the command named after the package; if the README names another one, use uvx --from mneme-hq <command>

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "mneme-decision-mcp": {
            "command": "uvx",
            "args": [
                "mneme-hq"
            ]
        }
    }
}
```
uvx runs the command named after the package; if the README names another one, use uvx --from mneme-hq <command>

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "mneme-decision-mcp": {
            "type": "stdio",
            "command": "uvx",
            "args": [
                "mneme-hq"
            ]
        }
    }
}
```
uvx runs the command named after the package; if the README names another one, use uvx --from mneme-hq <command>

### Gemini CLI

**Platform CLI**
```bash
gemini mcp add mneme-decision-mcp uvx mneme-hq
```
uvx runs the command named after the package; if the README names another one, use uvx --from mneme-hq <command>

## When to use it
- query architectural decisions that apply to specific modules or source files
- submit draft architectural proposals directly from coding agents
- trace the origin and context behind past engineering choices
- prevent unintended architecture drift during automated code edits

## Example prompts
- Check Mneme for architectural decisions that apply to our database layer.
- Search project memory for decisions regarding authentication standards.
- Propose a draft architectural decision for caching API responses.

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NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md