settings.json — the six lines that matter

One file makes every machine behave identically.

~/.claude/settings.json holds your defaults. The studio's runs 42 lines; yours starts at six.

How it thinks. What runs. What stops interrupting.

Every key does one of three jobs: deciding how Claude thinks (model, effort, thinking), deciding what runs without asking (permissions), and deleting friction you've resolved once and mean forever.

Six lines, complete and valid as shown.

{
  "permissions": {
    "defaultMode": "default"
  },
  "alwaysThinkingEnabled": true
}

A cautious permission default plus extended thinking on every turn. Grow it as each key earns its place — don't paste anyone's 42-line file wholesale.

Five keys worth knowing.

• 01permissions.defaultMode "auto" — the resting autonomy rung
• 02model — pin the daily driver; [1m] requests million-token context
• 03alwaysThinkingEnabled + effortLevel "xhigh" — fewer shallow answers
• 04agentPushNotifEnabled true — ping when a long agent finishes
• 05autoCompactEnabled false — compact deliberately, not automatically

Two commands catch every typo.

$ jq . ~/.claude/settings.json
# pretty-prints, or names the broken line
# (a trailing comma is the classic)

$ claude
> /config
# the live settings panel - what actually loaded

Most keys are read at startup. When an edit seems ignored, restart the session before you debug the JSON.

Which file wins.

The settings ritual.

• cat ~/.claude/settings.json — see what you have
• Start with the six-line core, grow deliberately
• jq . to validate; /config to confirm it loaded
• Taste goes global, contracts go project, exceptions go local
• Restart the session before debugging an ignored key

One idea from one lesson.

Track 1 (23 lessons) is free.