vercel-preview

vercel-preview is a skill for Claude Code from elevanaltd/HestAI-MCP. It costs 22 tokens per session (1,398 once invoked), scanned A, original, Apache-2.0.

A set of instructions for accessing Vercel preview deployments, which are temporary hosted versions of a project, when deployment protection blocks automated tools.

In plain words
What is it for?
Use it in continuous integration, UI validation, or end-to-end tests to wait for a Vercel preview and access it with the configured automation secret.
Why use it?
It gives CI and automated browser tests a documented way to reach protected previews without removing the protection for normal users.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Good fit Use it in continuous integration, UI validation, or end-to-end tests to wait for a Vercel preview and access it with the configured automation secret.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/elevanaltd/hestai-mcp/vercel-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 elevanaltd/HestAI-MCP --skill vercel-preview
Clone the repo
git clone --depth 1 https://github.com/elevanaltd/HestAI-MCP

Made for: Claude Code.

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 vercel-preview

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/elevanaltd/hestai-mcp/vercel-preview"><img src="https://agentmods.dev/badge/skills/elevanaltd/hestai-mcp/vercel-preview.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 22 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,398 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00022 $0.01398
Opus 5 $0.00011 $0.00699
Sonnet 5 $0.00004 $0.00280
Haiku 4.5 $0.00002 $0.00140

Measured 5d ago against content hash 29292fd3e690, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

vercel-preview scanned grade A with 1 finding 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 5d ago.

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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -I -H "x-vercel-protection-bypass: $VERCEL_AUTOMATION_BYPASS_SECRET" \
src/hestai_mcp/_bundled_hub/library/skills/vercel-preview/SKILL.md · 198 lines

How it starts

The opening of the file, as written. The whole thing — 198 lines — stays where its author put it; the contents beside it link to each section on GitHub.

===VERCEL_PREVIEW=== META: TYPE::SKILL VERSION::1.0 STATUS::ACTIVE COMPRESSION_TIER::AGGRESSIVE DOMAIN::HEPHAESTUS[tool_crafting]⊕HERMES[automation]

§1::PURPOSE

Enable automated access to Vercel protected preview deployments for CI/CD, UI validation, and E2E testing

§2::PROTECTION_BYPASS_PATTERN

METHOD::Protection_Bypass_for_Automation

SECRET_NAME::VERCEL_AUTOMATION_BYPASS_SECRET

SECRET_LOCATIONS::[
  vercel_dashboard::"Project Settings -> Deployment Protection -> Auto-injected",
  github_secrets::"Repository Settings -> Secrets -> Actions",
  local_dev::".env.local[GITIGNORED]"
]

ACCESS_METHODS::[
  HTTP_HEADER::"x-vercel-protection-bypass: ${VERCEL_AUTOMATION_BYPASS_SECRET}",
  QUERY_PARAM::"?x-vercel-protection-bypass=${VERCEL_AUTOMATION_BYPASS_SECRET}"
]

§3::CI_WORKFLOW_INTEGRATION

§4::GITHUB_ACTIONS_PATTERN

# .github/workflows/ci.yml
jobs:
  integration-tests:
    runs-on: ubuntu-latest
    steps:
      - name: Wait for Vercel Preview
        uses: patrickedqvist/[email protected]
        id: vercel
        with:
          token: ${{ secrets.GITHUB_TOKEN }}
          max_timeout: 300

      - name: Run E2E Tests
        env:
          VERCEL_PREVIEW_URL: ${{ steps.vercel.outputs.url }}
          VERCEL_AUTOMATION_BYPASS_SECRET: ${{ secrets.VERCEL_AUTOMATION_BYPASS_SECRET }}
        run: npm run test:e2e

§5::PLAYWRIGHT_CONFIGURATION

// playwright.config.ts
import { defineConfig } from '@playwright/test';

export default defineConfig({
  use: {
    baseURL: process.env.VERCEL_PREVIEW_URL,
    extraHTTPHeaders: {
      'x-vercel-protection-bypass': process.env.VERCEL_AUTOMATION_BYPASS_SECRET || '',
    },
  },
});

§6::CHROME_DEVTOOLS_MCP_ACCESS

CHROME_DEVTOOLS_PATTERN::[
  // Navigate with bypass query param
  mcp__chrome-devtools__navigate_page(
    url: "${VERCEL_PREVIEW_URL}?x-vercel-protection-bypass=${SECRET}"
  ),

  // OR set header via evaluate_script before navigation
  mcp__chrome-devtools__evaluate_script(
    function: "() => { /* custom fetch with header */ }"
  )
]

§7::SETUP_CHECKLIST

PREREQUISITES::[
  1::vercel_pro_plan_or_higher[automation_bypass_is_paid_feature],
  2::deployment_protection_enabled[Project_Settings->Deployment_Protection],
  3::automation_bypass_generated[generates_VERCEL_AUTOMATION_BYPASS_SECRET]
]

CONFIGURATION::[
  1::add_to_github_secrets[repository_settings->secrets->actions],
  2::add_to_local_env[.env.local_for_local_testing],
  3::update_ci_workflow[pass_secret_to_test_steps],
  4::configure_playwright[extraHTTPHeaders_or_query_param],
  5::verify_access[curl_with_header_returns_200]
]

VERIFICATION_COMMAND::
  curl -I -H "x-vercel-protection-bypass: $VERCEL_AUTOMATION_BYPASS_SECRET" \
    https://your-preview-url.vercel.app
  # Should return 200, not 401/403

§8::SECURITY_CONSIDERATIONS

NEVER::[
  commit_secret_to_git,
  log_secret_in_CI_output,
  share_secret_in_documentation,
  use_secret_in_client_side_code
]

ALWAYS::[
  use_github_secrets_for_CI,
  use_gitignored_.env.local_for_local,
  rotate_if_exposed,
  limit_to_preview_deployments[not_production]
]

ROTATION::[
  location::"Vercel Dashboard -> Project -> Settings -> Deployment Protection",
  action::"Regenerate secret",
  update::"GitHub Secrets + local .env.local"
]

§9::TROUBLESHOOTING

ISSUE::401_Unauthorized_despite_bypass[
  CHECK::[
    secret_correct_and_not_stale,
    header_name_exact["x-vercel-protection-bypass"],
    secret_passed_to_env_in_CI,
    not_trying_production_URL[bypass_for_previews_only]
  ]
]

ISSUE::Preview_not_found[
  CHECK::[
    PR_created_and_pushed,
    vercel_integration_enabled,
    wait_for_deployment_complete[use_wait-for-vercel-preview_action]
  ]
]

ISSUE::Bypass_not_available[
  CHECK::[
    vercel_plan[Pro_or_higher_required],
    deployment_protection_enabled_first,
    feature_may_require_team_admin
  ]
]

§10::AGENT_INTEGRATION

UI_VALIDATOR_USAGE::[
  RECEIVES::[preview_url, acceptance_criteria],
  ACCESSES::preview_via_bypass_header,
  VALIDATES::visual+functional_requirements,
  RETURNS::PASS/FAIL+evidence
]

CI_PIPELINE_USAGE::[
  TIER_1::quality_gates[no_preview_needed],
  TIER_2::preview_integration[uses_bypass_for_E2E],
  PATTERN::wait_for_preview->export_url->run_tests_with_bypass
]

Read the full file on GitHub · 198 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. 5d ago First seen · 198 lines · 22 tokens per session scan A 29292fd3e690

Subscribe to this mod's changes

vercel-preview is a skill published in the GitHub repository elevanaltd/HestAI-MCP (0 stars, last pushed yesterday), licensed Apache-2.0. It adds 22 tokens to every session and 1,398 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.