preview

preview is a skill for Claude Code, Codex from tobihagemann/turbo. It costs 81 tokens per session (895 once invoked), scanned A, original, MIT.

A way to start a project's live app and let a person try a change before the work is finalized.

In plain words
What is it for?
Use it to preview web or desktop changes, test user-facing flows, and decide what should be adjusted based on hands-on feedback.
Why use it?
It provides direct user feedback on whether a visible change feels correct, rather than relying only on code checks.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: names the AskUserQuestion tool.

Good fit Use it to preview web or desktop changes, test user-facing flows, and decide what should be adjusted based on hands-on feedback.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/tobihagemann/turbo/preview
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add tobihagemann/turbo --skill preview
Clone the repo
git clone --depth 1 https://github.com/tobihagemann/turbo

Made for: Claude Code, Codex.

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.

agentmods badge for preview

README.md
[![agentmods](https://agentmods.dev/badge/skills/tobihagemann/turbo/preview/github.svg)](https://agentmods.dev/skills/tobihagemann/turbo/preview)
Your own site
<a href="https://agentmods.dev/skills/tobihagemann/turbo/preview"><img src="https://agentmods.dev/badge/skills/tobihagemann/turbo/preview/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.

agentmods 80×15 button for preview

Your own site · 80×15
<a href="https://agentmods.dev/skills/tobihagemann/turbo/preview"><img src="https://agentmods.dev/badge/skills/tobihagemann/turbo/preview.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 81 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 895 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 pass 7 Sept 2026
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00081 $0.00895
Opus 5 $0.00041 $0.00447
Sonnet 5 $0.00016 $0.00179
Haiku 4.5 $0.00008 $0.00089

Measured today against content hash d1296a7908f2, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

preview 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 today.

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.

claude/skills/preview/SKILL.md · 55 lines

How it starts

The opening of the file, as written. The whole thing — 55 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Preview

Bring up the running app and let the user drive it themselves to judge the change, then act on their verdict.

Step 1: Determine Scope

Resolve what to preview using the first match:

  1. User-specified — the user says what to look at. Use that.
  2. PR — a PR URL or number is provided. Fetch its details and read the changed code.
  3. Conversation context — prior conversation contains recent work. Extract what changed, where it lives, and the expected behavior.
  4. App-level discovery — fresh context with no prior work. Examine entry points, routes, and the README to identify the app's core user-facing flows.

If the resolved scope has no user-visible surface to try (a CLI-only change, a library with no entry point, backend work with no UI to look at), present this message: "Nothing to preview — ." Then use the TaskList tool and proceed to any remaining task.

Step 2: Determine Launch Approach

Check for a project-specific skill or MCP tool that launches the app, and use it if present. Otherwise use the fallback for the surface type:

  • Web app → start the dev server; the access point is the local URL and port
  • Desktop/native app → build and launch the app so its window is open

Step 3: Bring Up the Stack

Start backend services and frontend together — a frontend-only change still needs the backend running to be exercised. Build first if the project requires a build step.

Start long-running processes with the Bash tool (run_in_background: true) and wait until each reports ready. Pass run_in_background alone, never with a trailing &: backgrounding twice reports success within seconds while the servers are either dead with the wrapper or orphaned still holding the port. Confirm each process bound to its port before sending it traffic, since a readiness probe passes just as well against an orphan from an earlier attempt. Capture each process's PID and stop it by that PID and its process group, rather than by port or command-line pattern, which also match a concurrent agent's server. Tail their logs with the Monitor tool so backend errors and warnings surface while the user is trying the app.

Read the full file on GitHub · 55 lines

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.

  1. today Changed d1296a7908f2
  2. 2d ago Changed · +1 lines 3a5d2f8d830c
  3. 10d ago First seen · 54 lines · 81 tokens per session scan A 66a0d71788ab

Subscribe to this mod's changes

preview is a skill published in the GitHub repository tobihagemann/turbo (402 stars, last pushed today), licensed MIT. It adds 81 tokens to every session and 895 once invoked, about $0.0004 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 2026-08-30.

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