A read-only connector for searching Mobbin, a library of real app interface screenshots. It sends searches for apps, screens, user flows, and interface elements through an agent.

Use it for visual interface research before designing or building an app.

It helps an agent find concrete examples of how real products handle interface patterns and multi-step journeys.

mcp-mobbin — Skill for Claude Code and OpenCode by MichelKerkmeester

Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo

git clone --depth 1 https://github.com/MichelKerkmeester/skilled-agent-harness_spec-driven-loops

agentmods

npx agentmods add skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/mcp-mobbin

Made for: Claude Code, OpenCode.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/mcp-mobbin/github.svg)](https://agentmods.dev/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/mcp-mobbin)

Your own site

<a href="https://agentmods.dev/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/mcp-mobbin"><img src="https://agentmods.dev/badge/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/mcp-mobbin/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/mcp-mobbin"><img src="https://agentmods.dev/badge/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/mcp-mobbin.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 41 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 9,176 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

NVIDIA SkillSpector warn 7 Sept 2026

SkillSpector: 8 findings, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

medium MCP Rug Pull · line 4
npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.

Fix: Pin the version: npx @scope/[email protected]
medium Data Exfiltration · line 288
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
medium Data Exfiltration · line 374
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
medium Data Exfiltration · line 388
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
medium MCP Rug Pull · line 288
npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.

Fix: Pin the version: npx @scope/[email protected]
medium MCP Rug Pull · line 388
npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.

Fix: Pin the version: npx @scope/[email protected]
medium Excessive Agency · line 299
Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.

Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
medium MCP Rug Pull · line 376
npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.

Fix: Pin the version: npx @scope/[email protected]

How audits are shown

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00041	$0.09176
Opus 5	$0.00020	$0.04588
Sonnet 5	$0.00008	$0.01835
Haiku 4.5	$0.00004	$0.00918

Measured 2d ago against content hash d1dea40d6af6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

mcp-mobbin scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/doctor.sh, scripts/install.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.opencode/skills/mcp-tooling/mcp-mobbin/SKILL.md · 417 lines

How it starts

The opening of the file, as written. The whole thing — 417 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Mobbin (mcp-mobbin)

Search Mobbin's library of real app UI screenshots ("the world's largest library of real app UI screenshots" per the official repo) from an agent through the Mobbin MCP via Code Mode: one documented tool, search_screens, answering app, screen, flow, and element research as query intents. This packet is a read-only TRANSPORT (packetKind: transport, mutatesWorkspace: false): every call goes against the external hosted Mobbin service, never this repo, and it produces no design tokens or Style Reference of its own. When a measured Style Reference of real, extracted design tokens is also wanted, pair with sk-design-md-generator. Deep operational detail lives in references/tool-surface.md and references/mcp-wiring.md.

Discovery status (read first). The mobbin Code Mode manual IS REGISTERED in this repo's .utcp_config.json (registered 2026-07-16 by an operator; this packet never edits the config), and live discovery RAN 2026-07-16, pre-auth (fixture: references/discovery-fixture-2026-07-16.json): list_tools returned THREE read tools — registry names mobbin.mobbin.{search_screens,search_flows,search_sections} (dot-separated), TS callables mobbin.mobbin_search_screens(...) etc. per the fixture's Access as: lines — superseding the research's one-public-tool baseline. Operator browser OAuth is still pending for CALLS. Per-session tool_info re-confirmation stays MANDATORY before relying on any name: confirm, then call, and fail closed on drift.

Access trap. Mobbin MCP access is documented for Pro, Team, and Enterprise — not Free. Authentication is browser OAuth only (DCR + PKCE S256, openid scope): no static API key or auth env var exists for MCP — that question is answered in the negative, not open. Unauthenticated calls return HTTP 401. The service is rate-limited to 60 requests per 60 seconds per user.

Read the full file on GitHub · 417 lines

Files

What ships with it

41 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2d ago Changed d1dea40d6af6
9d ago First seen · 417 lines · 41 tokens per session scan A 40ef07958ebc

Subscribe to this mod's changes

mcp-mobbin is a skill published in the GitHub repository MichelKerkmeester/skilled-agent-harness_spec-driven-loops (35 stars, last pushed today), licensed MIT. It adds 41 tokens to every session and 9,176 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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