9 items tagged “prompt-caching”
Some LLM providers offer a feature where common prompt prefixes can be cached, providing a performance boost and price reduction.
2025
We've adjusted prompt caching so that you now only need to specify cache write points in your prompts - we'll automatically check for cache hits at previous positions. No more manual tracking of read locations needed.
— Alex Albert, Anthropic
2024
Anthropic: Message Batches (beta) (via) Anthropic now have a batch mode, allowing you to send prompts to Claude in batches which will be processed within 24 hours (though probably much faster than that) and come at a 50% price discount.
This matches the batch models offered by OpenAI and by Google Gemini, both of which also provide a 50% discount.
Update 15th October 2024: Alex Albert confirms that Anthropic batching and prompt caching can be combined:
Don't know if folks have realized yet that you can get close to a 95% discount on Claude 3.5 Sonnet tokens when you combine prompt caching with the new Batches API
Gemini 1.5 Flash-8B is now production ready (via) Gemini 1.5 Flash-8B is "a smaller and faster variant of 1.5 Flash" - and is now released to production, at half the price of the 1.5 Flash model.
It's really, really cheap:
- $0.0375 per 1 million input tokens on prompts <128K
- $0.15 per 1 million output tokens on prompts <128K
- $0.01 per 1 million input tokens on cached prompts <128K
Prices are doubled for prompts longer than 128K.
I believe images are still charged at a flat rate of 258 tokens, which I think means a single non-cached image with Flash should cost 0.00097 cents - a number so tiny I'm doubting if I got the calculation right.
OpenAI's cheapest model remains GPT-4o mini, at $0.15/1M input - though that drops to half of that for reused prompt prefixes thanks to their new prompt caching feature (or by half if you use batches, though those can’t be combined with OpenAI prompt caching. Gemini also offer half-off for batched requests).
Anthropic's cheapest model is still Claude 3 Haiku at $0.25/M, though that drops to $0.03/M for cached tokens (if you configure them correctly).
I've released llm-gemini 0.2 with support for the new model:
llm install -U llm-gemini
llm keys set gemini
# Paste API key here
llm -m gemini-1.5-flash-8b-latest "say hi"
OpenAI DevDay: Let’s build developer tools, not digital God
I had a fun time live blogging OpenAI DevDay yesterday—I’ve now shared notes about the live blogging system I threw other in a hurry on the day (with assistance from Claude and GPT-4o). Now that the smoke has settled a little, here are my impressions from the event.
[... 2,090 words]Introducing Contextual Retrieval (via) Here's an interesting new embedding/RAG technique, described by Anthropic but it should work for any embedding model against any other LLM.
One of the big challenges in implementing semantic search against vector embeddings - often used as part of a RAG system - is creating "chunks" of documents that are most likely to semantically match queries from users.
Anthropic provide this solid example where semantic chunks might let you down:
Imagine you had a collection of financial information (say, U.S. SEC filings) embedded in your knowledge base, and you received the following question: "What was the revenue growth for ACME Corp in Q2 2023?"
A relevant chunk might contain the text: "The company's revenue grew by 3% over the previous quarter." However, this chunk on its own doesn't specify which company it's referring to or the relevant time period, making it difficult to retrieve the right information or use the information effectively.
Their proposed solution is to take each chunk at indexing time and expand it using an LLM - so the above sentence would become this instead:
This chunk is from an SEC filing on ACME corp's performance in Q2 2023; the previous quarter's revenue was $314 million. The company's revenue grew by 3% over the previous quarter.
This chunk was created by Claude 3 Haiku (their least expensive model) using the following prompt template:
<document>
{{WHOLE_DOCUMENT}}
</document>
Here is the chunk we want to situate within the whole document
<chunk>
{{CHUNK_CONTENT}}
</chunk>
Please give a short succinct context to situate this chunk within the overall document for the purposes of improving search retrieval of the chunk. Answer only with the succinct context and nothing else.
Here's the really clever bit: running the above prompt for every chunk in a document could get really expensive thanks to the inclusion of the entire document in each prompt. Claude added context caching last month, which allows you to pay around 1/10th of the cost for tokens cached up to your specified beakpoint.
By Anthropic's calculations:
Assuming 800 token chunks, 8k token documents, 50 token context instructions, and 100 tokens of context per chunk, the one-time cost to generate contextualized chunks is $1.02 per million document tokens.
Anthropic provide a detailed notebook demonstrating an implementation of this pattern. Their eventual solution combines cosine similarity and BM25 indexing, uses embeddings from Voyage AI and adds a reranking step powered by Cohere.
The notebook also includes an evaluation set using JSONL - here's that evaluation data in Datasette Lite.
Examples are the #1 thing I recommend people use in their prompts because they work so well. The problem is that adding tons of examples increases your API costs and latency. Prompt caching fixes this. You can now add tons of examples to every prompt and create an alternative to a model finetuned on your task with basically zero cost/latency increase. […]
This works even better with smaller models. You can generate tons of examples (test case + solution) with 3.5 Sonnet and then use those examples to create a few-shot prompt for Haiku.
DeepSeek API introduces Context Caching on Disk (via) I wrote about Claude prompt caching this morning. It turns out Chinese LLM lab DeepSeek released their own implementation of context caching a couple of weeks ago, with the simplest possible pricing model: it's just turned on by default for all users.
When duplicate inputs are detected, the repeated parts are retrieved from the cache, bypassing the need for recomputation. This not only reduces service latency but also significantly cuts down on overall usage costs.
For cache hits, DeepSeek charges $0.014 per million tokens, slashing API costs by up to 90%.
[...]
The disk caching service is now available for all users, requiring no code or interface changes. The cache service runs automatically, and billing is based on actual cache hits.
DeepSeek currently offer two frontier models, DeepSeek-V2 and DeepSeek-Coder-V2, both of which can be run as open weights models or accessed via their API.
Prompt caching with Claude (via) The Claude API now supports prompt caching, allowing you to mark reused portions of long prompts (like a large document provided as context). Claude will cache these for up to five minutes, and any prompts within that five minutes that reuse the context will be both significantly faster and will be charged at a significant discount: ~10% of the cost of sending those uncached tokens.
Writing to the cache costs money. The cache TTL is reset every time it gets a cache hit, so any application running more than one prompt every five minutes should see significant price decreases from this. If you app prompts less than once every five minutes you'll be losing money.
This is similar to Google Gemini's context caching feature, but the pricing model works differently. Gemini charge $4.50/million tokens/hour for their caching (that's for Gemini 1.5 Pro - Gemini 1.5 Flash is $1/million/hour), for a quarter price discount on input tokens (see their pricing).
Claude’s implementation also appears designed to help with ongoing conversations. Using caching during an individual user’s multi-turn conversation - where a full copy of the entire transcript is sent with each new prompt - could help even for very low traffic (or even single user) applications.
Here's the full documentation for the new Claude caching feature, currently only enabled if you pass "anthropic-beta: prompt-caching-2024-07-31" as an HTTP header.
Interesting to note that this caching implementation doesn't save on HTTP overhead: if you have 1MB of context you still need to send a 1MB HTTP request for every call. I guess the overhead of that HTTP traffic is negligible compared to the overhead of processing those tokens once they arrive.
One minor annoyance in the announcement for this feature:
Detailed instruction sets: Share extensive lists of instructions, procedures, and examples to fine-tune Claude's responses. [...]
I wish Anthropic wouldn't use the term "fine-tune" in this context (they do the same thing in their tweet). This feature is unrelated to model fine-tuning (a feature Claude provides via AWS Bedrock). People find this terminology confusing already, frequently misinterpreting "fine-tuning" as being the same thing as "tweaking your prompt until it works better", and Anthropic's language here doesn't help.
Context caching for Google Gemini (via) Another new Gemini feature announced today. Long context models enable answering questions against large chunks of text, but the price of those long prompts can be prohibitive - $3.50/million for Gemini Pro 1.5 up to 128,000 tokens and $7/million beyond that.
Context caching offers a price optimization, where the long prefix prompt can be reused between requests, halving the cost per prompt but at an additional cost of $4.50 / 1 million tokens per hour to keep that context cache warm.
Given that hourly extra charge this isn't a default optimization for all cases, but certain high traffic applications might be able to save quite a bit on their longer prompt systems.
It will be interesting to see if other vendors such as OpenAI and Anthropic offer a similar optimization in the future.
Update 14th August 2024: Anthropic's Claude now has its own version of prompt caching.