Impact Preview
Preview filesystem, config, and API side effects before your coding agent runs destructive or irreversible tool calls.
Overview
Impact Preview is a MCP server for the Ship phase that shows what an AI agent would change before any action executes.
What is this MCP server?
- Surfaces a diff-style impact summary before the agent commits to a tool invocation
- Stdio MCP transport (PyPI package impact-preview v0.2.1) for Claude Code, Cursor, and Codex
- Designed for write operations: file edits, shell, deploy hooks, and chained multi-step plans
- Complements human approval workflows without replacing code review or formal security audits
- Open source on GitHub (agent-polis/impact-preview)
- MCP server version 0.2.1
- Transport: stdio
- Package registry: PyPI (identifier impact-preview)
Community signal: 1 GitHub stars.
What problem does it solve?
Agents approve tool calls instantly, so you often only learn about broken configs or deleted files after the damage is done.
Who is it for?
Solo builders letting agents edit repos, run shell commands, or touch deploy configs who want a mandatory preview gate.
Skip if: Teams that only need read-only research agents with no write tools, or those who already enforce human-in-the-loop via a separate enterprise policy engine.
What do I get? / Deliverables
You get a clear pre-flight view of proposed changes so you can approve, edit, or cancel agent actions before they run.
- Pre-execution impact summaries for planned agent tool calls
- Safer approve-or-cancel decisions before writes and commands run
- Reduced accidental repo or environment damage from autonomous agents
Recommended MCP Servers
Journey fit
Change-impact preview belongs on the Ship shelf because solo builders need guardrails right before agent actions land in repos, cloud, or production-adjacent environments. Security subphase covers pre-execution risk review—not full pentesting, but the same “don’t ship surprise damage” mindset agents often skip.
How it compares
Pre-execution impact MCP server, not a post-merge code review skill or a full SAST scanner.
Common Questions / FAQ
Who is impact-preview for?
Indie and solo developers using AI coding agents with write access who want to see diffs and side effects before tools run.
When should I use impact-preview?
Use it whenever an agent is about to modify files, run commands, or call APIs where mistakes are costly or hard to undo.
How do I add impact-preview to my agent?
Install the PyPI package impact-preview, register it as a stdio MCP server in Claude Code or Cursor, and point your agent workflow at the preview tools before execute steps.