karanb192

Cache Tax — Development skill for Claude Code

Development community

Keep Claude Code’s prompt cache warm during breaks and show the estimated cost before a cold send.

How to install Cache Tax

This entry records only its repository, not the path inside it, so there is no exact command to give. Open karanb192/cache-tax and copy the folder into ~/.claude/skills/, or the file into ~/.claude/agents/.

What Cache Tax does

Keep Claude Code’s prompt cache warm during breaks and show the estimated cost before a cold send.

Alternatives in Development

Cost Xray — See what Claude Code and Codex actually send to the API — and what each part costs 586 ★
Bm Stats — Show the basemind dashboard — resource footprint (disk + RAM) and activity (tool calls, per-tool histogram, es 94 ★
Ctx Handoff Mod — Claude Code mod: auto handoff to a fresh conversation when context hits a threshold, keeps the prompt cache wa 25 ★

README

cache-tax

**Keep Claude Code's prompt cache warm during breaks.**

On Fable 5.1, a one-hour cache write costs **80x a cache read per token**: [$20 versus $0.25 per million tokens](https://platform.claude.com/docs/en/about-claude/pricing). Run `/keepwarm` before stepping away. If you return cold, the guard stops your send once with the estimated rewrite price.

**[Install](#install)** · [How it works](#how-it-works) · [Costs and limits](#cost-and-the-plan-limit-question) · [Commands](#commands)

![Real recording of cache-tax stopping a cold send with a $6.61 estimate](site/assets/refusal.gif)

A two-line recap in a 330k-token session triggered a **$6.61 estimate**. After resending, the reported cache write was **$6.28**. Recorded on 2.1.1; current wording says “up to” the estimated token count. These are API-equivalent costs, not extra subscription charges.

Install

Needs early-access function hooks, a one-hour cache and Claude Code left running. Pings cost tokens, including uncapped output.

claude plugin marketplace add karanb192/claude-code-mods
claude plugin install cache-tax@claude-code-mods

Start Claude Code with function hooks enabled:

CLAUDE_CODE_ENABLE_FUNCTION_HOOKS=1 claude

In a warm session, run `/keepwarm` to arm six hours. Use `/keepwarm 90m` for a shorter window, or `/keepwarm off` to stop.

**Check the cache lifetime.** Included subscription usage defaults to one hour for the main conversation; API-key and usage-credit requests default to five minutes. Forks belong to a separate bucket. The [documented controls](https://code.claude.com/docs/en/prompt-caching#choose-the-ttl-yourself) are `promptCacheTtl` for the main conversation and `subagentPromptCacheTtl` for requests outside it; each accepts `"1h"`. A 50-minute timer does not protect a five-minute cache. See [Limits](#limits) for the evidence boundaries.

**No function hooks yet?** The [hook version](https://github.com/karanb192/claude-code-hooks/tree/main/plugins/cach