Prompt Cache TTL Switch

Writes one key in settings.json. Everything else in that file is preserved.

Help

If the argument is -h, --help, or help, read references/help.md and follow it, then stop.

Step 1: Pick the mode

Step 2: Run the script

Paste the locator block from references/run-script.md (the only place this skill spells the path), then:

sh "$_CC" 1h
sh "$_CC" 5m

The script targets ${CLAUDE_CONFIG_DIR:-$HOME/.claude}/settings.json, so a multi-account setup switches accounts by exporting CLAUDE_CONFIG_DIR before the call.

Do not hand-write jq or sed against settings.json instead. The script is the contract; a one-off edit is how an unrelated key gets dropped.

Step 3: Report

On exit 0, print [OK] followed by the script's own three lines verbatim:

[OK] cache TTL: 5m -> 1h  (env.ENABLE_PROMPT_CACHING_1H: (unset) -> 1)
file: /home/you/.claude/settings.json
Restart Claude Code to pick it up.

On any non-zero exit, print [FAIL] exit=<n> and relay the script's stderr verbatim, then stop — see Failure modes.

What the script does

• 1h -> .env.ENABLE_PROMPT_CACHING_1H = "1"
• 5m -> deletes that key, and drops .env entirely if it becomes empty
• missing settings.json -> creates {} first, then patches
• reads to a temp file and mvs it into place, so a jq failure cannot truncate the real file

Failure modes — read the exit, do not work around it

Constraints

• Touches exactly one key. Never edit model, hooks, permissions, or statusLine from this skill.
• Requires jq. There is no degraded mode.
• Self-contained: the script depends on nothing outside this skill directory.

Related Skills

claudecode:statusline-setup installs the status line into the same settings.json using the same lossless merge.