What I Learned Pushing Prompt Engineering to the Limit | by Jacob Marks, Ph.D. | Jun, 2023


Satirical depiction of immediate engineering. Paradoxically, the DALL-E2 generated picture was generated by the creator utilizing immediate engineering with the immediate “a mad scientist handing over a scroll to an artificially clever robotic, generated in a retro model”, plus a variation, plus outpainting.

I spent the previous two months constructing a large-language-model (LLM) powered utility. It was an thrilling, intellectually stimulating, and at occasions irritating expertise. My whole conception of immediate engineering — and of what’s doable with LLMs — modified over the course of the mission.

I’d like to share with you a few of my largest takeaways with the purpose of shedding gentle on a few of the usually unstated points of immediate engineering. I hope that after studying about my trials and tribulations, it is possible for you to to make extra knowledgeable immediate engineering selections. When you’d already dabbled in immediate engineering, I hope that this helps you push ahead in your personal journey!

For context, right here is the TL;DR on the mission we’ll be studying from:

  • My crew and I constructed VoxelGPT, an utility that mixes LLMs with the FiftyOne laptop imaginative and prescient question language to allow looking out by way of picture and video datasets through pure language. VoxelGPT additionally solutions questions on FiftyOne itself.
  • VoxelGPT is open supply (so is FiftyOne!). All the code is available on GitHub.
  • You possibly can strive VoxelGPT free of charge at gpt.fiftyone.ai.
  • When you’re curious how we constructed VoxelGPT, you’ll be able to read more about it on TDS here.

Now, I’ve break up the immediate engineering classes into 4 classes:

  1. General Lessons
  2. Prompting Techniques
  3. Examples
  4. Tooling

Science? Engineering? Black Magic?

Immediate engineering is as a lot experimentation as it’s engineering. There are an infinite variety of methods to put in writing a immediate, from the precise wording of your query, to the content material and formatting of the context you feed in. It may be overwhelming. I discovered it best to start out easy and construct up an instinct — after which check out hypotheses.

In laptop imaginative and prescient, every dataset has its personal schema, label sorts, and sophistication names. The purpose for VoxelGPT was to have the ability to work with any laptop imaginative and prescient dataset, however we began with only a single dataset: MS COCO. Preserving all the extra levels of freedom mounted allowed us to nail down into the LLM’s means to put in writing syntactically right queries within the first place.

When you’ve decided a formulation that’s profitable in a restricted context, then work out learn how to generalize and construct upon this.

Which Mannequin(s) to Use?

Individuals say that probably the most vital traits of enormous language fashions is that they’re comparatively interchangeable. In concept, it is best to be capable to swap one LLM out for one more with out considerably altering the connective tissue.

Whereas it’s true that altering the LLM you employ is usually so simple as swapping out an API name, there are undoubtedly some difficulties that come up in follow.

  • Some fashions have a lot shorter context lengths than others. Switching to a mannequin with a shorter context can require main refactoring.
  • Open supply is nice, however open supply LLMs should not as performant (but) as GPT fashions. Plus, if you’re deploying an utility with an open supply LLM, you will have to verify the container operating the mannequin has sufficient reminiscence and storage. This will find yourself being extra troublesome (and dearer) than simply utilizing API endpoints.
  • When you begin utilizing GPT-4 after which change to GPT-3.5 due to price, you could be shocked by the drop-off in efficiency. For sophisticated code technology and inference duties, GPT-4 is MUCH higher.

The place to Use LLMs?

Massive language fashions are highly effective. However simply because they could be able to sure duties doesn’t imply it’s good to — and even ought to — use them for these duties. One of the best ways to consider LLMs is as enablers. LLMs should not the WHOLE answer: they’re simply part of it. Don’t anticipate giant language fashions to do every little thing.

For instance, it could be the case that the LLM you might be utilizing can (underneath ideally suited circumstances) generate correctly formatted API calls. But when you understand what the construction of the API name ought to seem like, and you might be truly desirous about filling in sections of the API name (variable names, situations, and so forth.), then simply use the LLM to do these duties, and use the (correctly post-processed) LLM outputs to generate structured API calls your self. This shall be cheaper, extra environment friendly, and extra dependable.

A whole system with LLMs will certainly have a whole lot of connective tissue and classical logic, plus a slew of conventional software program engineering and ML engineering parts. Discover what works finest on your utility.

LLMs Are Biased

Language fashions are each inference engines and information shops. Oftentimes, the information retailer facet of an LLM might be of nice curiosity to customers — many individuals use LLMs as search engine replacements! By now, anybody who has used an LLM is aware of that they’re inclined to creating up faux “information” — a phenomenon known as hallucination.

Generally, nevertheless, LLMs undergo from the alternative downside: they’re too firmly fixated on information from their coaching information.

In our case, we had been making an attempt to immediate GPT-3.5 to find out the suitable ViewStages (pipelines of logical operations) required in changing a consumer’s pure language question into a sound FiftyOne Python question. The issue was that GPT-3.5 knew in regards to the `Match` and `FilterLabels` ViewStages, which have existed in FiftyOne for a while, however its coaching information did not embrace not too long ago added performance whereby a `SortBySimilarity` ViewStage can be utilized to search out photos the resemble a textual content immediate.

We tried passing in a definition of `SortBySimilarity`, particulars about its utilization, and examples. We even tried instructing GPT-3.5 that it MUST NOT use the `Match` or `FilterLabels` ViewStages, or else will probably be penalized. It doesn’t matter what we tried, the LLM nonetheless oriented itself in direction of what it knew, whether or not it was the proper alternative or not. We had been preventing in opposition to the LLM’s instincts!

We ended up having to take care of this situation in post-processing.

Painful Put up-Processing Is Inevitable

Regardless of how good your examples are; irrespective of how strict your prompts are — giant language fashions will invariably hallucinate, offer you improperly formatted responses, and throw a tantrum once they don’t perceive enter data. Essentially the most predictable property of LLMs is the unpredictability of their outputs.

I spent an ungodly period of time writing routines to sample match for and proper hallucinated syntax. The post-processing file ended up containing nearly 1600 strains of Python code!

A few of these subroutines had been as easy as including parenthesis, or altering “and” and “or” to “&” and “|” in logical expressions. Some subroutines had been much more concerned, like validating the names of the entities within the LLM’s responses, changing one ViewStage to a different if sure situations had been met, guaranteeing that the numbers and forms of arguments to strategies had been legitimate.

If you’re utilizing immediate engineering in a considerably confined code technology context, I’d suggest the next method:

  1. Write your personal customized error parser utilizing Summary Syntax Timber (Python’s ast module).
  2. If the outcomes are syntactically invalid, feed the generated error message into your LLM and have it strive once more.

This method fails to handle the extra insidious case the place syntax is legitimate however the outcomes should not proper. If anybody has a great suggestion for this (past AutoGPT and “present your work” model approaches), please let me know!

The Extra the Merrier

To construct VoxelGPT, I used what appeared like each prompting method underneath the solar:

  • “You might be an skilled”
  • “Your job is”
  • “You MUST”
  • “You may be penalized”
  • “Listed here are the principles”

No mixture of such phrases will guarantee a sure kind of habits. Intelligent prompting simply isn’t sufficient.

That being stated, the extra of those methods you utilize in a immediate, the extra you nudge the LLM in the proper route!

Examples > Documentation

It is not uncommon information by now (and customary sense!) that each examples and different contextual data like documentation may also help elicit higher responses from a big language mannequin. I discovered this to be the case for VoxelGPT.

When you add all the straight pertinent examples and documentation although, what must you do you probably have further room within the context window? In my expertise, I discovered that tangentially associated examples mattered greater than tangentially associated documentation.

Modularity >> Monolith

The extra you’ll be able to break down an overarching downside into smaller subproblems, the higher. Relatively than feeding the dataset schema and an inventory of end-to-end examples, it’s far more efficient to establish particular person choice and inference steps (selection-inference prompting), and feed in solely the related data at every step.

That is preferable for 3 causes:

  1. LLMs are higher at doing one job at a time than a number of duties without delay.
  2. The smaller the steps, the better to sanitize inputs and outputs.
  3. It is a vital train for you because the engineer to know the logic of your utility. The purpose of LLMs isn’t to make the world a black field. It’s to allow new workflows.

How Many Do I Want?

A giant a part of immediate engineering is determining what number of examples you want for a given job. That is extremely downside particular.

For some duties (effective query generation and answering questions based on the FiftyOne documentation), we had been capable of get away with out any examples. For others (tag selection, whether or not chat history is relevant, and named entity recognition for label classes) we simply wanted just a few examples to get the job completed. Our fundamental inference job, nevertheless, has nearly 400 examples (and that’s nonetheless the limiting consider general efficiency), so we solely move in essentially the most related examples at inference time.

When you find yourself producing examples, attempt to comply with two tips:

  1. Be as complete as doable. In case you have a finite area of prospects, then attempt to give the LLM at the very least one instance for every case. For VoxelGPT, we tried to have on the very least one instance for every syntactically right approach of utilizing each ViewStage — and sometimes just a few examples for every, so the LLM can do sample matching.
  2. Be as constant as doable. If you’re breaking the duty down into a number of subtasks, ensure the examples are constant from one job to the following. You possibly can reuse examples!

Artificial Examples

Producing examples is a laborious course of, and handcrafted examples can solely take you thus far. It’s simply not doable to think about each doable state of affairs forward of time. If you deploy your utility, you’ll be able to log consumer queries and use these to enhance your instance set.

Previous to deployment, nevertheless, your finest wager may be to generate artificial examples.

Listed here are two approaches to producing artificial examples that you just may discover useful:

  1. Use an LLM to generate examples. You possibly can ask the LLM to differ its language, and even imitate the model of potential customers! This didn’t work for us, however I’m satisfied it may work for a lot of purposes.
  2. Programmatically generate examples — doubtlessly with randomness — primarily based on parts within the enter question itself. For VoxelGPT, this implies producing examples primarily based on the fields within the consumer’s dataset. We’re within the strategy of incorporating this into our pipeline, and the outcomes we’ve seen thus far have been promising.


LangChain is widespread for a purpose: the library makes it simple to attach LLM inputs and outputs in complicated methods, abstracting away the gory particulars. The Fashions and Prompts modules particularly are high notch.

That being stated, LangChain is certainly a piece in progress: their Reminiscences, Indexes, and Chains modules all have vital limitations. Listed here are only a few of the problems I encountered when making an attempt to make use of LangChain:

  1. Doc Loaders and Textual content Splitters: In LangChain, Document Loaders are supposed to rework information from totally different file codecs into textual content, and Text Splitters are supposed to separate textual content into semantically significant chunks. VoxelGPT solutions questions in regards to the FiftyOne documentation by retrieving essentially the most related chunks of the docs and piping them right into a immediate. With the intention to generate significant solutions to questions in regards to the FiftyOne docs, I needed to successfully construct customized loaders and splitters, as a result of LangChain didn’t present the suitable flexibility.
  2. Vectorstores: LangChain provides Vectorstore integrations and Vectorstore-based Retrievers to assist discover related data to include into LLM prompts. That is nice in concept, however the implementations are missing in flexibility. I needed to write a customized implementation with ChromaDB with a purpose to move embedding vectors forward of time and never have them recomputed each time I ran the appliance. I additionally needed to write a customized retriever to implement the customized pre-filtering I wanted.
  3. Query Answering with Sources: When constructing out query answering over the FiftyOne docs, I arrived at an affordable answer using LangChain’s `RetrievalQA` Chain. Once I wished so as to add sources in, I assumed it might be as easy as swapping out that chain for LangChain’s `RetrievalQAWithSourcesChain`. Nevertheless, unhealthy prompting methods meant that this chain exhibited some unlucky habits, reminiscent of hallucinating about Michael Jackson. As soon as once more, I needed to take matters into my own hands.

What does all of this imply? It might be simpler to simply construct the parts your self!

Vector Databases

Vector search could also be on 🔥🔥🔥, however that doesn’t imply you NEED it on your mission. I initially applied our comparable instance retrieval routine utilizing ChromaDB, however as a result of we solely had a whole lot of examples, I ended up switching to a precise nearest neighbor search. I did must take care of all the metadata filtering myself, however the end result was a quicker routine with fewer dependencies.


Including TikToken into the equation was extremely simple. In complete, TikToken added <10 strains of code to the mission, however allowed us to be far more exact when counting tokens and making an attempt to suit as a lot data as doable into the context size. That is the one true no-brainer on the subject of tooling.

There are tons of LLMs to select from, a lot of shiny new instruments, and a bunch of “immediate engineering” methods. All of this may be each thrilling and overwhelming. The important thing to constructing an utility with immediate engineering is to:

  1. Break the issue down; construct the answer up
  2. Deal with LLMs as enablers, not as end-to-end options
  3. Solely use instruments once they make your life simpler
  4. Embrace experimentation!

Go construct one thing cool!

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