# Prism

A local MCP server that hands your agent the right files before an edit and checks what the change left behind. Your code stays on the machine.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI · ★ 10
- Author: Shailesh200
- License: MIT · policy=link-only · description only; the file stays with the author
- Source: https://github.com/Shailesh200/prism
- Updated: 2026-10-19
- HTML: https://affpapa.org/en/nevibecode/mcp/prism

## What it does

Prism indexes your repository locally and answers the agent from that index. Before an edit it names the files and tests tied to the task, plus helpers worth reusing instead of rewriting. During the edit it points at a file from your own repo to copy, so new code matches the surrounding style. Afterward it runs the checks the change reaches and returns one verdict: `SHIP`, `NOT PROVEN` with the cheapest check to prove it, or `NO-SHIP`.

Nine MCP tools ship by default; the rest are opt-in through `extraTools` in `~/.prism/config.json`. Review lenses come in Dev, Architect and QA flavors, and you can add your own with `prism lens`. The CLI and the agent read the same index, so both give the same answers.

Analysis makes no network requests, and a trap suite fails the build if one shows up. The single exception is a once-a-day npm registry check for updates, switched off with `PRISM_SKIP_SELF_UPDATE=1`. Installation is global, so Node.js and npm need to be present.

## Requirements
- Needs: Node.js (commands run via npx)
- Environment variables: `PRISM_WORKSPACE`, `CURSOR_API_KEY`, `PRISM_DISPATCH_ROLE` — keys and tokens: ask the human for the values, never commit them or put them in shared files.

## Install

### Claude Code (native platform)

**Platform CLI**
```bash
claude mcp add --env PRISM_WORKSPACE=<PRISM_WORKSPACE> --env CURSOR_API_KEY=<CURSOR_API_KEY> --env PRISM_DISPATCH_ROLE=<PRISM_DISPATCH_ROLE> --transport stdio prism -- npx -y @repo-prism/mcp-server
```
Replace <…> with your own values

### Codex

**Platform CLI**
```bash
codex mcp add prism --env PRISM_WORKSPACE=<PRISM_WORKSPACE> --env CURSOR_API_KEY=<CURSOR_API_KEY> --env PRISM_DISPATCH_ROLE=<PRISM_DISPATCH_ROLE> -- npx -y @repo-prism/mcp-server
```
Replace <…> with your own values

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "prism": {
            "command": "npx",
            "args": [
                "-y",
                "@repo-prism/mcp-server"
            ],
            "env": {
                "PRISM_WORKSPACE": "<PRISM_WORKSPACE>",
                "CURSOR_API_KEY": "<CURSOR_API_KEY>",
                "PRISM_DISPATCH_ROLE": "<PRISM_DISPATCH_ROLE>"
            }
        }
    }
}
```
Replace <…> with your own values

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "prism": {
            "type": "stdio",
            "command": "npx",
            "args": [
                "-y",
                "@repo-prism/mcp-server"
            ],
            "env": {
                "PRISM_WORKSPACE": "<PRISM_WORKSPACE>",
                "CURSOR_API_KEY": "<CURSOR_API_KEY>",
                "PRISM_DISPATCH_ROLE": "<PRISM_DISPATCH_ROLE>"
            }
        }
    }
}
```
Replace <…> with your own values

### Gemini CLI

**Platform CLI**
```bash
gemini mcp add -e PRISM_WORKSPACE=<PRISM_WORKSPACE> -e CURSOR_API_KEY=<CURSOR_API_KEY> -e PRISM_DISPATCH_ROLE=<PRISM_DISPATCH_ROLE> prism npx -y @repo-prism/mcp-server
```
Replace <…> with your own values

## When to use it
- find the files and tests a task touches before editing
- spot callers left dangling by a change
- work out which tests reach a given file
- get a verdict on a change instead of checking by hand
- add custom review lenses for a team

## Example prompts
- What breaks if I change `src/index.ts`?
- Prepare a change: I need to rewrite error handling in the API
- Review my changes with the QA lens

## Similar
- [REA](https://affpapa.org/en/nevibecode/mcp/rea.md) — MCP server · ★ 386989
- [GitHub](https://affpapa.org/en/nevibecode/mcp/github.md) — MCP server · ★ 33918
- [Netdata](https://affpapa.org/en/nevibecode/mcp/netdata.md) — MCP server · ★ 81115
- [browser-use](https://affpapa.org/en/nevibecode/mcp/browser-use.md) — MCP server · ★ 119160
- [Codebase Memory](https://affpapa.org/en/nevibecode/mcp/codebase-memory.md) — MCP server · ★ 47392
- [mcp-server](https://affpapa.org/en/nevibecode/mcp/mcp-server.md) — MCP server · ★ 43872

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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