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Prompt-caching – auto-injects Anthropic cache breakpoints (90% token savings)

prompt-caching.ai

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Re: Prompt-caching – auto-injects Anthropic cache breakpoints (90% token savings)

#21

Post by CGamesPlay »

fschuett wrote: post #17

Slightly off-topic, but I recently tested some tool and it turns out Opus is far cheaper than Sonnet, because it produces way less output tokens and those are what's expensive. It's also much slower than Opus (I did 9 runs to compare Haiku, Sonnet and Opus on the same problem). I also thought "oh, Sonnet is more light-weight and cheaper than Opus", no, that's actually just marketing.

Claude subscriptions (strangely) have a Sonnet limit which is lower than the general model limit. Using Sonnet counts against both limits, using Opus only the general limit. So the subscriptions are discouraging Sonnet use as well.

Re: Prompt-caching – auto-injects Anthropic cache breakpoints (90% token savings)

#22

Post by derrida »

orphea wrote: post #20
numlocked wrote: post #19

As per its own FAQ this plugin is out of date and doesn’t actually do anything incremental re:caching: > "Hasn't Anthropic's new auto-caching feature solved this?" > Largely, yes — Anthropic's automatic caching (passing "cache_control": {"type": "ephemeral"} at the top level) handles breakpoint placement automatically now. This plugin predates that feature and originally filled that gap.

I don't understand and I'm curious, why a dead on arrival open source tool needs a separate domain? Domain Name: prompt-caching.ai Updated Date: 2026-03-12T20:31:44Z Creation Date: 2026-03-12T20:27:35Z Registry Expiry Date: 2028-03-12T20:27:35Z

Is it perhaps because this is for claude code but there's other tools that use anthropics api like custom agents? (some i prefer to use than claude code - e.g sketch.dev what is now called shelley at exe.dev) perhaps?

Re: Prompt-caching – auto-injects Anthropic cache breakpoints (90% token savings)

#24

Post by stingraycharles »

derrida wrote: post #22
orphea wrote: post #20

Earlier quoted context omitted.

I don't understand and I'm curious, why a dead on arrival open source tool needs a separate domain? Domain Name: prompt-caching.ai Updated Date: 2026-03-12T20:31:44Z Creation Date: 2026-03-12T20:27:35Z Registry Expiry Date: 2028-03-12T20:27:35Z

Is it perhaps because this is for claude code but there's other tools that use anthropics api like custom agents? (some i prefer to use than claude code - e.g sketch.dev what is now called shelley at exe.dev) perhaps?

No, because this doesn’t actually “fix” any existing code. It’s only useful for helping an LLM to modify your code to adjust the caching parameters in the right place, but it doesn’t have the correct API for that.

Re: Prompt-caching – auto-injects Anthropic cache breakpoints (90% token savings)

#25

Post by stingraycharles »

ermis wrote: post #14
spiderfarmer wrote: post #3

Will this work for Cowork as well?

No. Claude.ai is a consumer product — you have no access to the API layer underneath it. cache_control is an API-level feature only. This plugin works exclusively when you're making direct Anthropic API calls, either through the SDK in your own code or through MCP-compatible clients like Claude Code, Cursor, Windsurf, etc.

How would it work when you’re making Anthropic API calls? Wouldn’t an LLM have to invoke this, and as such, somehow the LLM needs to invoke this MCP tool (which is done using a tool call ie an answer from the LLM) before sending the request to Anthropic?

I am so confused why you chose an MCP server to solve this, wouldn’t a regular API at least have some merit in how it could be used (in that it doesnt require an LLM to invoke it) ?

Re: Prompt-caching – auto-injects Anthropic cache breakpoints (90% token savings)

#26

Post by jasonlotito »

katspaugh wrote: post #10

> This plugin is built for developers building their own applications with the Anthropic API. > Important note for Claude Code users: Claude Code already handles prompt caching automatically for its own API calls — system prompts, tool definitions, and conversation history are cached out of the box. Source: their GitHub

Does anyone actually read anymore?

From the FAQ:

You're right, and it's a fair question. Claude Code does handle prompt caching automatically for its own API calls — system prompts, tool definitions, and conversation history are cached out of the box. You don't need this plugin for that.

This plugin is for a different layer: when you build your own apps or agents with the Anthropic SDK. Raw SDK calls don't get automatic caching unless you place cache_control breakpoints yourself. This plugin does that automatically, plus gives you visibility into what's being cached, hit rates, and real savings — which Claude Code doesn't expose.

> Claude Code already handles prompt caching automatically for its own API calls

Claude Code is an app. The API layer is different.

When did people start thinking that the Claude Code app and the API are the same thing?

Are these just all confused vibe coders?

Re: Prompt-caching – auto-injects Anthropic cache breakpoints (90% token savings)

#27

Post by user34283 »

jasonlotito wrote: post #26
katspaugh wrote: post #10

> This plugin is built for developers building their own applications with the Anthropic API. > Important note for Claude Code users: Claude Code already handles prompt caching automatically for its own API calls — system prompts, tool definitions, and conversation history are cached out of the box. Source: their GitHub

Does anyone actually read anymore? From the FAQ: You're right, and it's a fair question. Claude Code does handle prompt caching automatically for its own API calls — system prompts, tool definitions, and conversation history are cached out of the box. You don't need this plugin for that. This plugin is for a different layer: when you build your own apps or agents with the Anthropic SDK. Raw SDK calls don't get automa…

Is this a joke?

The first thing on the page is "Automatic prompt caching for Claude Code."

Why should one expect this to actually be "Automatic prompt caching for new apps you develop with Claude Code"?

It appears to be hard to explain what this plugin does, and the authors did a terrible job; they did not even try.

Re: Prompt-caching – auto-injects Anthropic cache breakpoints (90% token savings)

#29

Post by imjonse »

orphea wrote: post #20
numlocked wrote: post #19

As per its own FAQ this plugin is out of date and doesn’t actually do anything incremental re:caching: > "Hasn't Anthropic's new auto-caching feature solved this?" > Largely, yes — Anthropic's automatic caching (passing "cache_control": {"type": "ephemeral"} at the top level) handles breakpoint placement automatically now. This plugin predates that feature and originally filled that gap.

I don't understand and I'm curious, why a dead on arrival open source tool needs a separate domain? Domain Name: prompt-caching.ai Updated Date: 2026-03-12T20:31:44Z Creation Date: 2026-03-12T20:27:35Z Registry Expiry Date: 2028-03-12T20:27:35Z

It's more likely the other way around, the .ai domain with a fairly generic and maybe future-proof name needed a quick vibecoded project to not be empty when it launches.

Re: Prompt-caching – auto-injects Anthropic cache breakpoints (90% token savings)

#30

Post by thepasch »

numlocked wrote: post #19

As per its own FAQ this plugin is out of date and doesn’t actually do anything incremental re:caching: > "Hasn't Anthropic's new auto-caching feature solved this?" > Largely, yes — Anthropic's automatic caching (passing "cache_control": {"type": "ephemeral"} at the top level) handles breakpoint placement automatically now. This plugin predates that feature and originally filled that gap.

I’m pretty sure whoever made this didn’t read the website they asked their LLM to generate for them.
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