Preflight

Preflight Check

Run a full environment health check before starting session work. Reads a declared-state file and verifies each entry.

Arguments

• No arguments: full check of everything in declared-state
• --fix: enable auto-fix mode (confirms before each fix)
• --quiet: only show failures, skip green rows

Setup

Create ~/.claude/preflight-state.json to declare what to check. Example:

{
  "keychain_keys": [
    { "service": "GEMINI_API_KEY", "label": "Gemini API Key" },
    { "service": "FIGMA_ACCESS_TOKEN", "label": "Figma Token", "expires": "2026-06-24", "warn_days_before": 30 }
  ],
  "env_files": [
    {
      "path": "~/.claude/my-project.env.local",
      "required_vars": ["API_TOKEN", "PROJECT_ID"],
      "expected_perms": "600"
    }
  ],
  "mcp_servers": [
    { "name": "slack", "type": "http", "url": "http://localhost:PORT/health" },
    { "name": "google-calendar", "type": "stdio", "command": "npx" }
  ],
  "gcp": {
    "expected_account": "you@yourdomain.com",
    "expected_project": "your-gcp-project-id"
  },
  "github": {
    "expected_user": "your-github-username",
    "expected_email": "you@yourdomain.com"
  }
}

If the file is missing, Claude will tell you and offer to generate a default.

Execution Steps

Step 0: Load Declared State

Read ~/.claude/preflight-state.json. Parse it and extract all check categories. Initialize a results array to collect status for the final table.

Step 1: Keychain Keys

For each entry in keychain_keys, run:

security find-generic-password -a "$USER" -s "SERVICE_NAME" -w >/dev/null 2>&1 && echo "OK" || echo "MISSING"

Do NOT capture or display the key value. Only check existence.

For keys with an expires field, calculate days until expiry from today. If within warn_days_before, mark as WARN with the expiry date.

Record result:

• OK: key exists in Keychain
• WARN: key exists but approaching expiry
• FAIL: key missing from Keychain

Step 2: Env Files

For each entry in env_files:

1. Check file exists and has correct permissions:

[ -f FILE_PATH ] && stat -f "%Lp" FILE_PATH

1. Check required vars are present (existence only, never display values):

grep -q '^VAR_NAME=.\+' FILE_PATH && echo "SET" || echo "EMPTY"

Never cat, head, or display env file contents.

Auto-fix wrong permissions (if --fix):

chmod 600 FILE_PATH

Step 3: MCP Server Connectivity

HTTP servers: Test with a HEAD request:

curl -s -o /dev/null -w "%{http_code}" --max-time 5 URL

• 200-399: OK
• 401/403: WARN (reachable, auth issue)
• 0 or 5xx: FAIL

stdio servers: Check command availability:

command -v COMMAND >/dev/null 2>&1 && echo "OK" || echo "MISSING"

Step 4: GCP Auth

gcloud auth list --filter=status:ACTIVE --format="value(account)" 2>/dev/null
gcloud config get-value project 2>/dev/null

Compare against gcp.expected_account and gcp.expected_project.

Step 5: GitHub Identity

gh auth status 2>&1
git config --global user.email

Compare against github.expected_user and github.expected_email.

Step 6: Output Status Table

## Preflight Results - [DATE]

| #  | Check                     | Status | Detail                          |
|----|---------------------------|--------|---------------------------------|
| 1  | Keychain: GEMINI_API_KEY  | OK     | Present                         |
| 2  | Keychain: FIGMA_TOKEN     | WARN   | Expires 2026-06-24 (84 days)   |
| 3  | Env: my-project.env.local | OK     | Exists, perms 600, vars set     |
| 4  | MCP: slack                | OK     | HTTP 200                        |
| 5  | GCP: auth                 | OK     | you@domain.com / project-id     |
| 6  | GitHub: identity          | OK     | username / you@domain.com       |

Status: OK = passed, WARN = caveats, FAIL = blocked.

Summary line:

• All OK: "Preflight complete. All N checks passed."
• Warnings: "Preflight complete. N passed, W warnings."
• Failures: "Preflight BLOCKED. F failures must be resolved before starting work."

Rules

• Never display, echo, or log any secret values. Check existence via exit codes only.
• Never use cat, head, or Read on env files. Use grep -q only.
• Auto-fixes require user confirmation before executing.
• If a check category is missing from preflight-state.json, skip it silently.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Damon-Stewart-1
• Source: Damon-Stewart-1/claude-skills-public
• License: MIT

Install and usage instructions live in the source repository linked above.