Claude Code permissions: safe auto-approval with defaultMode/allow/deny

Remove repeated prompts while still blocking risky actions — verified live.

Fewer prompts, but block the risky stuff

Claude Code asks for approval on writes and shell commands by default. `permissions` in `settings.json` lets you auto-approve routine actions while still blocking dangerous ones.

The permissions object

`allow`, `deny`, `ask`, `defaultMode` (behavior for anything unmatched), and `additionalDirectories`.

{
  "permissions": {
    "defaultMode": "acceptEdits",
    "allow": ["Read", "Edit", "Bash(npm test)"],
    "deny": ["Bash(rm -rf*)", "Bash(git push --force*)"],
    "additionalDirectories": ["/Users/you/Downloads"]
  }
}

Valid defaultMode values

`default`, `acceptEdits`, `plan`, `dontAsk`, and `bypassPermissions` (isolated environments only). `acceptEdits` is a reasonable everyday default.

Live-tested: does deny really block?

In a test project with `deny: ["Bash(rm -rf*)"]`, running `claude -p` and asking it to run `rm -rf` returned: "Permission to use Bash with command rm -rf ... has been denied." The command never ran.

A gotcha we hit live: workspace trust

On a first-time project folder, Claude Code warned the workspace wasn't trusted and ignored some `allow` entries. You need to run it interactively once and accept the trust dialog (or set `hasTrustDialogAccepted` in `~/.claude.json`) before `allow` fully applies.

Permissions vs hooks

`permissions.deny` is a flat declarative rule; a `PreToolUse` hook can inspect context dynamically. Use `deny` for simple always-block patterns, hooks when you need to look at the actual command.

FAQ

What defaultMode values exist?

default, acceptEdits, plan, dontAsk, and bypassPermissions.

Does deny really block dangerous commands?

Yes — verified live: setting `Bash(rm -rf*)` in deny caused the command to be refused.

Why am I still prompted despite allow entries?

A first-time project folder may be untrusted, ignoring some allow entries until you accept the trust dialog interactively.

permissions vs hooks?

Use deny for simple always-block rules; use PreToolUse hooks when you need to inspect the actual command.

When should I use bypassPermissions?

Only in isolated environments like containers — not for everyday development.

Secure your keys with KeyDeck →Find configs with permissions set →See School →