pattern-mcpBLOCK
Pattern checks a coding agent's UI decisions against your own design system before it builds, whether that lives in code or in Figma. It helps the agent reuse what the product already has and build only what is actually missing. An opt-in enforcement boundary can make that check required, and every
Overview
From the repository's own README, as read at the audited commit. Badges and raw HTML are left out.
[](https://github.com/donaldrichard19-LVD/pattern-mcp/actions/workflows/publish.yml) [](https://www.npmjs.com/package/pattern-mcp) [](https://www.npmjs.com/package/pattern-mcp) [](./LICENSE)
Pattern checks a coding agent's UI decisions against your own design system before it builds, whether that lives in code or in Figma. It helps the agent reuse what the product already has and build only what is actually missing. An opt-in enforcement boundary can make that check required, and every decision is recorded in an auditable ledger you can verify later.
Website · npm · Report an issue
Contents (click to expand)
- Install · What Pattern Does · How it works · Quick Start · Recommended workflow · Try it · Validation examples
- Enforcement boundary: hook + CI gate (require the call, don't just log it)
- Core tools (on by default -- see Tool tiers):
register_design_system·recommend_component·extract_requirements·verify_component·record_component_decision - Advanced tools (
PATTERN_TOOLS=full):get_figma_evidence·read_ledger· [report_build_cost](#tool-report_bu
e08425db2c67OBSERVED · 2026-10-10Connect
Built from this server's own package name, version and transport as found in its source — not copied from anyone's documentation, so it cannot drift against a page we do not control. Replace the environment placeholders with a token scoped to the least it needs.
claude mcp add pattern-website --env ANTHROPIC_API_KEY=${ANTHROPIC_API_KEY} --env FIGMA_ACCESS_TOKEN=${FIGMA_ACCESS_TOKEN} --env FIGMA_FILE_KEY=${FIGMA_FILE_KEY} --env GITHUB_TOKEN=${GITHUB_TOKEN} -- npx -y [email protected]{
"mcpServers": {
"pattern-website": {
"command": "npx",
"args": [
"-y",
"[email protected]"
],
"env": {
"ANTHROPIC_API_KEY": "${ANTHROPIC_API_KEY}",
"FIGMA_ACCESS_TOKEN": "${FIGMA_ACCESS_TOKEN}",
"FIGMA_FILE_KEY": "${FIGMA_FILE_KEY}",
"GITHUB_TOKEN": "${GITHUB_TOKEN}"
}
}
}
}Exposed tools (1)
1 read · 0 write · 0 destructive.
| Tool | Risk | Description |
|---|---|---|
Button | read |
Trust audit
BLOCKgrade D · trust 66/100 Do not install this without reading the findings. The audit found something that could harm you or your machine.
| Layer | What it checks | Result |
|---|---|---|
| L0 | Provenance & inventory | PASS |
| L1 | Static analysis of the code | FAIL |
| L2 | Instruction surface (what it tells the agent) | PASS |
| L3 | Class-specific surface | PASS |
| L4 | Behavioural (sandbox) | SKIPPED |
What the source does
- Filesystem
- declared (4 observation(s))
- Network
- declared (10 observation(s))
- Shell
- declared (7 observation(s))
- Dependencies
- not all pinned
- Secrets in source
- none-found
Findings (15)
const many = exec(["src/A.tsx", ".github/workflows/pattern-gate.yml", ".pattern/receipts/x.json", "website/components/B.tsx"].join("\n"));const evil = exec([`src/a$(touch ${pwned}).tsx`, "src/b;touch " + pwned + ".tsx", "src/ok name.tsx"].join("\n"));arguments: { replace: true, project_id: "escape-project", manifest_path: "/etc/hosts" },for (const bad of ["/etc/passwd", "../outside.tsx", " "]) {const env = { ...process.env, FIGMA_API_URL: `http://127.0.0.1:${srv.address().port}`, FIGMA_ACCESS_TOKEN: GOOD, HOME: home };PATTERN_ANTHROPIC_URL: "http://127.0.0.1:9",
env: { ...process.env, PATTERN_TELEMETRY: "1", PATTERN_POSTHOG_HOST: "http://127.0.0.1:1" },env: { ...process.env, PATTERN_TELEMETRY: "1", PATTERN_POSTHOG_HOST: "http://127.0.0.1:1" },for (const id of u.searchParams.get("ids").split(",")) images[id] = `http://127.0.0.1:${figmaStub.address().port}/img/${encodeURIComponent(id)}.png`;const key = `${sys}/${f.file}:${createHash("sha1").update(f.content).digest("hex").slice(0, 10)}`;return createHash("sha1").update(content).digest("hex").slice(0, 10);arguments: { replace: true, project_id: "escape-project-2", directory_path: "../../etc" },file_path: "../../../etc/passwd",
@modelcontextprotocol/sdk, @posthog/mcp, posthog-node, @types/node, typescript
lucide-react, next, posthog-js, react, react-dom, @types/node, @types/react, @types/react-dom
Gates applied: no_behavioural_pass.
e08425db2c67full audit observations/trust-audit/mcp-server/donaldrichard19-lvd__pattern-mcp.json · Report an issue / request a re-scanAudit history
Every audit this server has had. A grade with a past is a grade somebody is still checking.
| Date | Source | Verdict | Grade | Score | Change |
|---|---|---|---|---|---|
| 2026-10-10 | e08425db2c67 | BLOCK | D | 66 | first audit |
Questions
What is the pattern-mcp MCP server?
Pattern checks a coding agent's UI decisions against your own design system before it builds, whether that lives in code or in Figma. It helps the agent reuse what the product already has and build only what is actually missing. An opt-in enforcement boundary can make that check required, and every
What tools does pattern-mcp expose?
1 in total: 1 read-only, 0 that write, and 0 that can delete or overwrite. Every one is listed on this page with its risk.
Is pattern-mcp safe to connect to an agent?
No — not without reading the findings first. The audit graded it D (66/100) and found 2 critical or high issues in the source. Each one is listed on this page with the file and line it is on.
What credentials does pattern-mcp need?
It reads ANTHROPIC_API_KEY, FIGMA_ACCESS_TOKEN, FIGMA_FILE_KEY, GITHUB_TOKEN, NEXT_PUBLIC_POSTHOG_KEY, PATTERN_JEV_BATCH_TOKENS, PATTERN_POSTHOG_KEY and TYPESAFE_API_KEY from the environment. Give it a token scoped to the least it needs — an agent that can be talked into calling a tool can be talked into calling it with your credentials.
How does pattern-mcp run?
It speaks stdio, so it runs as a local process your client starts. It is published on npm as pattern-website at 0.1.0.
How current is this page?
The grade is for one exact copy of the source (e08425db2c67), read on 2026-10-10. The repository is watched and re-audited when it changes.