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AI Engineer Europe 2026

Connecting the Dots with Context Graphs

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Connecting the Dots with Context Graphs

Agents need more than relevant documents: connected domain knowledge, persistent memory, and recorded decision context let them retrieve the evidence behind a recommendation.

From a talk by Stephen Chin

Before you start: Familiarity with LLMs and retrieval-augmented generation is helpful; graph concepts are introduced as they are used.

When agents review work without its context

An agent can review an engineer’s pull request while still missing the business context behind the change. That context may live in Slack discussions, customer threads, and separate enterprise systems. Giving an agent responsibility for consequential decisions does not automatically give it access to the information those decisions require. Stephen Chin opens with this mismatch: engineers have increasingly capable tools, but incomplete control over what those tools know.

Slide titled “Today — Scattered, lost reasoning” shows CRM, Slack, Jira, Zendesk, PagerDuty and Zoom icons with question marks beside a figure holding two pills.
Scattered enterprise tools leave reasoning and context disconnected.

The Matrix metaphor makes the choice concrete. The blue pill leaves knowledge scattered across disconnected systems. The red pill connects enterprise data, previous decision traces, and tool calls into a system of reasoning. The goal is to make the context available together, so an application can use the relationships between facts when answering a question.

Chin points to Gartner’s recognition of context graphs on its AI hype cycle and Foundation Capital’s AI’s trillion-dollar opportunity: Context graphs as signs of growing interest. The essay’s title says trillion-dollar, rather than the three-trillion-dollar phrasing in the talk; its figure is an investment thesis. The technical question is how to build the connected information layer that such applications need.

0:400:57
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Represent the relationships explicitly

A knowledge graph represents people, things, and companies as nodes, attaches properties to them, and connects them through relationships. Chin’s small example has Dan living with Anne and driving her car. Those connections encode different facts: living with someone, driving a vehicle, and owning it are separate relationships. An embedding attached to the car adds another access path, allowing similarity search alongside explicit connections.

Using illustrative labels and relationship names, the Dan–Anne–car example can be represented in Cypher as follows. The car is one shared node, so a query can follow either its driver or its owner to the same object.

cypher

CREATE (dan:Person {name: 'Dan'}),
       (anne:Person {name: 'Anne'}),
       (car:Car),
       (dan)-[:LIVES_WITH]->(anne),
       (dan)-[:DRIVES]->(car),
       (anne)-[:OWNS]->(car)
RETURN dan, anne, car;

A vector representation can supplement this structure without replacing the facts encoded by its relationships.

The complementary roles are straightforward: an LLM supplies language capabilities, reasoning, and creativity; the graph supplies organized knowledge, context, and enrichment. Storing relationships together makes them available for retrieval, visualizing them helps people inspect the relevant connections, and analysing them can expose hidden patterns.

Slide titled “Context from graphs enables explainable AI” pairs a network graphic with three sections: Storing, Visualizing and Analysing.
Graph context supports storing, visualizing and analysing agent interactions.
3:183:34
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Retrieve the patient’s plan, not just advice about the disease

The retrieval example asks: What was the care plan associated with Andrea Jenkins’ emphysema? Knowing what emphysema is does not answer a question about one patient’s recorded care. Chin develops the comparison from a baseline LLM through vector retrieval to graph-grounded context.

ApproachContext usedResponse in the example
Baseline LLMGeneral medical knowledgePrevent further lung damage
Vector RAGRetrieved patient informationRespiratory therapy, deep breathing, coughing exercises
Graph-grounded retrievalPatient, diagnosis, and operation historyMedication management, smoking cessation counseling, pulmonary rehabilitation

The difference is the background connected to the patient. Chin identifies a smoking history and a previous operation as information lost in the similarity search but available in the graph-grounded example. This is an illustrative retrieval comparison, not a clinical evaluation.

The Matrix callback is Neo loading the knowledge needed to perform a task. For an agent, the corresponding capability comes from retrieving the relevant connected context before generating its answer.

4:374:49
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Add memory across interactions and decisions

Retrieval supplies grounding for the current question. The next layer is persistent agent memory, which preserves what has happened so later work can build on it. Chin separates that memory into three forms.

  • Short-term memory: The conversation, current agent pipeline, and state of activities underway. Persisting these in the graph preserves information needed during execution.
  • Long-term memory: Knowledge accumulated across longer tasks, procedures, and customer interactions. Its usefulness depends on a domain model that organizes business processes, entities, and participants.
  • Reasoning memory: Recorded decision provenance that helps explain a recommendation and supplies precedents for later decisions.

The last category needs a precise interpretation: a useful decision trace records the evidence, actions, and rationale available to the application; it does not imply access to a model’s hidden chain-of-thought. Retained provenance can support repeatability, compliance review, and debugging.

6:096:20
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Use similarity to enter the graph, then follow connections

Graphs provide a representation that both software and people can work with. An LLM can generate Cypher queries or extract graph structure from unstructured documents. A person can inspect the resulting nodes and relationships much as they would a diagram on a whiteboard. Relationships are first-class objects in this representation, rather than connections reconstructed through a series of table joins.

Chin describes multi-hop traversal as a performance advantage, without presenting a benchmark. He then combines several graph operations: FastRP produces graph embeddings; vector lookup can provide a starting point in the graph; and Louvain community grouping helps organize connected regions. Similarity and traversal serve different purposes: one locates a useful entry point, while the other follows explicit connections from it.

The open-source Neo4j Agent Memory package brings short-term, long-term, and reasoning memory together in a context graph. Chin connects this approach with explainable decisions and ACID-compliant storage, and invites contributions to the repository. The linked repository’s current APIs may differ from those used in the recording.

8:138:30
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Explore connected information in Lenny’s podcast

Podcasts make a useful test case because their information is dense and interconnected. A conversation about AI or product management can mention people, organizations, topics, and locations whose connections matter beyond any one passage. Chin’s Lenny’s Podcast Memory Explorer loads a podcast corpus and uses the three memory layers to support questions about it.

The agent receives tools built on the Neo4j Agent Memory APIs. In the demonstration, it retrieves locations mentioned in an episode, returning location records with coordinates. Chin describes using that information to build a map; the selected screen shows the returned locations and a successful Get Episode Locations tool result.

Lenny’s Memory interface displays a list of locations with coordinates and a successful Get Episode Locations tool result.
Lenny’s Memory returns locations mentioned in a podcast episode.

The purpose of the graph is to make the connected dataset navigable and dynamically queryable. Rather than asking only which location mentions resemble a query, the application can aggregate the locations associated with an episode. Chin describes this as a holistic view of the loaded data, compared with retrieving a partial set of similarity matches.

9:5710:14
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Write decision context back into memory

Cross-domain business questions require more than retrieving facts. They also require understanding why a previous decision was made. Chin distinguishes a context graph from a traditional audit log by the decision context it retains: entities and relationships connect evidence that might otherwise remain buried in Slack, email, or informal conversations. A new recommendation can then become part of the record available to the next interaction.

The architecture forms a feedback loop:

  1. Retrieve context. The agent uses context graph tools that combine knowledge graphs, vector search, and data science algorithms.
  2. Work through the request. Retrieved domain knowledge and earlier decision traces inform the agent’s recommendation.
  3. Record the new context. The agent loop pushes its output and associated trace into context memory, adding them to the graph.
  4. Reuse the history. Subsequent queries retrieve the accumulated traces alongside other relevant information.

The output of one interaction becomes evidence available to a later interaction. That is the mechanism that turns retrieval into an accumulating decision history.

11:3211:38
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Connect financial records to decision provenance

The financial services example gives the graph a concrete domain model. People and organizations are entities. Decisions, transactions, and approvals are events. Applied policies, risk factors, and employee reasoning provide the context for why those events occurred. Chin describes an open-source application that can be run locally, as well as a hosted version.

Chin describes a support ticket system, CRM, and internal business data system accessed through 10 MCP tools. Claude agents orchestrate the work, OpenAI embeddings supply vector representations, and Neo4j stores the resulting context. This separates orchestration from embedding generation: Claude does not itself compute OpenAI embeddings. The application maintains both a domain graph and a reasoning graph, then exposes them through a simple Next.js interface for end users.

12:5813:16
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Follow Jessica Norris’s loan recommendation

The demonstration asks whether Jessica Norris should receive approval. The application queries the graph for her history, including her bank account and related margin trades. It exposes model-issued Cypher queries and the graph being traversed and populated, making the retrieved information inspectable. The connected record also reveals a previous rejection—precisely the kind of prior decision that can disappear from view when systems remain separate.

The model recommends against giving Jessica the loan. Its response includes reasons, risk factors, earlier decisions, and fraud-detection patterns that it identifies as relevant to the risk. This is a recommendation presented to a human user, not a demonstrated execution of a loan denial. The person using the system can inspect the supporting context before making and defending a decision.

For developers, the value is a path from an agent’s answer back to the information used to produce it. Connected records and visible queries help users evaluate a recommendation; recorded decision context gives later interactions something more useful than an isolated final answer. Chin frames that grounded information as the practical business value of context graphs.

14:1614:28
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Try the memory layers in a graph database

Chin closes with a practical route to experimentation through Neo4j’s free education program. He introduces the GraphAcademy context graphs course and says the course provisions a free Aura instance in the background. That gives learners a graph database in which to try the techniques before bringing them into their own production or enterprise environment.

Neo4j Graph Academy slide with descriptive text, a QR code and the URL https://dev.neo4j.com/ga-rag.
Neo4j Graph Academy provides a resource for learning about generative AI and knowledge graphs.
16:1016:26
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Resources

From the talk

Read the complete timestamped transcript
  1. 0:00

    [upbeat music] Hello, and welcome everybody to Connecting the Dots with Context Graphs.

  2. 0:20

    My name is Stephen Chin. I run the developer relations team at Neo4j, and you are in store for the power hour of context and graphs and all this technology.

  3. 0:31

    So, um, I'm the first speaker. We have some other amazing talks after me. So I hope you enjoy all the great content which you're gonna see over the next, um, hour or so.

  4. 0:40

    So, what I'm gonna talk about is a bit about how we've all been feeling with the AI revolution, where we are trapped as engineers. We are using AI coding tools or, or maybe they're using us, where our work is being reviewed.

  5. 0:57

    Who, who here has their work reviewed by an agent when they check in their PRs? Yes, all of you. So we are, we're stuck in this limbo where we have amazing tools, we have amazing capabilities, but rather than us controlling them, they are controlling us.

  6. 1:14

    And we would like to get to a state where we're in control of this. So, we have to decide, is it going to be the, the blue pill where we're stuck inside of this mire of disparate knowledge, stuck in, in Slack discussions and little customer threads and different enterprise systems which are all segregated and

  7. 1:39

    siloed? And when, when we ask the agents to make critical business decisions or, or applications to make critical business decisions with, with all this spread, it can't possibly give good answers 'cause it doesn't have the context.

  8. 1:52

    Or do we wanna dive in and, and embrace the red pill, escape from the matrix, and have a system of reasoning where we actually have all these systems connected,

  9. 2:06

    all of our different enterprise data sources, previous decision traces, the reasoning tool, calls of the tools to give us a more consolidated view of our enterprise stack,

  10. 2:19

    and escape from the matrix? So who, who's, who's gonna... who's in the escape club? Who, who wants to break out? Okay. Hopefully, if you're in the room, you're, you're with me.

  11. 2:28

    Um, and guess who else is with us?

  12. 2:33

    Gartner [laughs] has now officially made context graphs as part of the AI hype cycle. So, we have been officially recognized by the, um, the analysts of the world. They, they also realize that we're all stuck in this, in this mire.

  13. 2:49

    Um, Foundation Capital actually started this thread with their three trillion dollar startup opportunity post about how context graphs are gonna move forward the industry and dramatically change how we build applications.

  14. 3:01

    And, uh, what I'll do is I'll, I'll show some demos, and I'll talk about how we can move from being stuck in this matrix, stuck in this world, and then become the superheroes of our organization and actually build the capability of the systems using technologies like knowledge graphs.

  15. 3:18

    So, knowledge graphs are a very powerful tool for us to aggregate all this information, create the connections, create the relationships. And at a fundamental level, they, they hold nodes, which are, are people or, or things or companies or relationships.

  16. 3:34

    Um, you, you have relationships between nodes where, um, in this case, um, you know Dan, those are properties, um, lives with Anne. They, he drives her car, apparently, so we know who, who wears the pants in this relationship.

  17. 3:49

    And we have some embeddings on top of the car, so we're embedding vector information in it, so we can also do similarity searches and kind of combine the best of both worlds with building information, but then also combining it with LLMs.

  18. 4:03

    So when we take what LLMs are really good at, this language, this reasoning, this creativity, when we combine that with what knowledge graphs are really effective at, so knowledge, context, and enrichment, then we can start doing things with our data like, um, storing all these relationships together, visualizing them, so we can get to the data which matters,

  19. 4:25

    finding hidden patterns, and then analyzing this and getting more insights, which will help power the context graph demonstrations, which I'm gonna show you all.

  20. 4:37

    So here's a, a simple example of how graphs power retrieval, because I think it's, it's good to understand what the difference is between a baseline LLM. So this is a, um, healthcare case.

  21. 4:49

    What was the care plan associated with Andrea Jenkins' emphysema?

  22. 4:53

    And when you ask the LLM, it has broad knowledge. It, it understands a lot of information. It knows what emphysema is. It knows what standard practice is. So it gives a, a very generic answer, preventing damage to the lungs, yada, yada, yada.

  23. 5:05

    Now, when we give it a RAG system, so we go to vector database, now it has more context. It knows a bit about the, the patient and their information, and it tells you, maybe recommend some activities like respiratory therapy, deep breathing, coughing exercises.

  24. 5:20

    So this is pretty generic medical advice. Now, where we wanna get to

  25. 5:26

    is grounded, complete information, where we're pulling in who's the patient, what was the previous diagnosis, what operations have they had? And you can see here that it, it's specifically me- recommending medication management, smoking cessation counseling, pulmonary rehabilitation exercises.

  26. 5:42

    So that, clearly, the parent here has a, the patient here has a history of, of smoking, has had an operation. So, like, there's, there's certain things which are background information that was lost in the similarity search.

  27. 5:55

    And if our agents had this information, then, like The Matrix, now we've loaded all up this information, and we can, you know, we're like Neo. We can do kung fu.

  28. 6:05

    We can shoot bullets. We can do all this amazing stuff.

  29. 6:09

    With the right memory structure in place. So this is kind of the second layer. So now we have the, the grounding with, with GraphRAG and retrieval, and we can pull things out of knowledge graphs.

  30. 6:20

    But we need to now store the, the memories, the short-term memory, the long-term memory, and the reasoning memory so that we have our complete history of what's happened and we can build on top of this.

  31. 6:32

    Um, so I think you all know that short-term memory is things which are happening in the current pipeline with agents, the conversation, the, the current state of, um, activities which your, your agent architecture is working on.

  32. 6:46

    So this can all be persistent in the knowledge graph, and it gives important information in the execution pipeline.

  33. 6:53

    Long-term memory is really important and needs to be organized well 'cause there's so much of it, so you have to figure out how to aggregate and pull this information in, have a good domain model for representing the, the different business processes, the entities, the, um, folks who are part of your application or part of your domain.

  34. 7:14

    And then you can actually store the information which your agents are working on over longer, um, tasks and procedures and across multiple different, um, user or customer interactions to give that history and context for what your application has done.

  35. 7:30

    And then finally, reasoning traces give us the ability to understand why decisions were made and how they're done. So typically, what we get from LLMs is we, we get the result, right?

  36. 7:42

    They'll, they'll tell us, "Well, this is what I recommend. This is, you know, advise this." But to get to that result, there's, there's thinking, there's reasoning, which happens behind the scenes, and we'd like to make it repeatable where that information, it's learning from the experience of the previous traces.

  37. 7:59

    It has that decision provenance for if there were previous decisions. You're going to draw on that knowledge, and we'll use that to come up with better future decisions. And this also gives us a great hook in for compliance and debugging.

  38. 8:13

    One of the great things about knowledge graphs is they're great for tooling, they're great for LLMs. LLMs can build Cypher, which is the query language for knowledge graphs. They can create knowledge graphs and create structure out of, um, unstructured documents, but it's also how we would represent things as humans.

  39. 8:30

    It's how we would draw things on a whiteboard. It's how we would show things. And with these, now we are loading up the memory

  40. 8:39

    into a structure where we can actually start to do interesting things with our memory. So graphs are a, a great use case for memory because relationships are first class within knowledge graphs.

  41. 8:53

    They're part of the structure. It's not like you have to join a bunch of tables together. It's a natural progression. They're highly performant for multi-hop traversal. Um, a lot of the GraphRAG research papers talk about this specifically as a major advantage to GraphRAG and graph AI architectures, where they can navigate more complex structures at a very performant

  42. 9:13

    speed. Um, using graph embeddings like FastRP, we can also do vector lookups, which is a great way to get a starting point or hook into the graph, where we navigate using algorithms like the Louvain algorithm for community grouping.

  43. 9:28

    And then we get explainable decisions. We have more cross-knowledge, and we're building ACID-compliant, um, solutions with things like the Neo4j Agent Memory package. So this is an open source package which we built on top of Neo4j.

  44. 9:44

    We have an open GitHub repo. We encourage other folks to contribute for it. And it brings these three concepts together, short-term memory, long-term memory, reasoning into a context graph structure.

  45. 9:57

    And the first demonstration I'm gonna show is an example of how you can build a knowledge graph which ties your short-term, your long-term memory, and your reasoning memory together to answer questions from Lenny's podcast.

  46. 10:14

    Who's a, who's a fan of Lenny's podcast in the room? Oh, okay. A bunch of folks. Um, it's a great resource and, um, but it's hard. Like, podcasts are hard.

  47. 10:23

    They're very dense. There's a lot of connected information and topics, and we'd like to be able to extract that and then understand more of the context and things which are happening with the help of AI.

  48. 10:35

    So, um, we built a little demo, Lenny Memory Podcast, again, an open source project. Um, what it lets you do is it has all the podcasts loaded up. Um, for those of you who don't know, Lenny talks a lot about different AI topics, about product management, and, um, one of the things we can do is we provide

  49. 10:54

    the AI with different tools for accessing the memory. This is all written on top of the Neo4j Agent Memory APIs. And then, for example, we're pulling back locations in the episode, and it's using that to design and build a graph and, or in this case, a, a map, and show us all the different locations of things mentioned

  50. 11:15

    in the film by aggregating all that context. And because we have it in a graph format, it's not just pulling out some similar locations and getting, like, part of the data.

  51. 11:24

    We get a holistic view of the entire data set, which can be navigated and queried dynamically.

  52. 11:32

    So now we've shown what we can do with graphs, what we can do with memory,

  53. 11:38

    but what we're all here for is, is context graphs, right? How can we take this and actually apply this to solve those cross-domain business problems where it's very hard to get the information, it's very hard to quantify why decisions are made.

  54. 11:53

    And, um, context graphs are really powerful for this because unlike a traditional audit log, they're capturing the, the why, the decision traces that happens while you're evaluating your models.

  55. 12:05

    It organizes these by entities and relationships. And then it's pulling all the knowledge from, from different sources. So rather than having conversations hidden in Slack or emails or other informal, um, conversations, now your app becomes a central point where they can look up previous decisions, they can get that advice, and then they can add that recommendation back

  56. 12:27

    to the reasoning traces for, um, future lookups. Broadly, the architecture is you're, you're searching, you're using your context graph retrieval tools from your agentic architecture. It's using a combination of knowledge graphs, vector search, and, um, data science algorithms.

  57. 12:44

    Then the... When you go through the agent loop, it's then pushing that back into the context memory, which gets added back into the graph, and subsequent queries are then pulling this back as part of your reasoning traces and your output to solve specific domain problems.

  58. 12:58

    So what I'm gonna show here as an example is a financial services application. Um, for this, we're going to have entities of different people and organizations, um, different events for decisions, transactions, and approvals which happen during the workflow of the application, and then the context of why.

  59. 13:16

    What policies were applied? What risk factors are there? What was the employee reasoning behind giving a certain recommendation? And the architecture, again, it's an open source project. You can try this out on...

  60. 13:29

    We have a hosted version of this, and you can try it out with a GitHub project and run it locally. But it's pulling in from a variety of different data sources.

  61. 13:37

    So we've hooked it up to a support ticket system, a CRM, and an internal business data system with 10 different MCP tools that it has access to. And then we've used our Claude agents to create OpenAI embeddings, and then populate a Neo4j context graph with a lot of this information so that it has a, a domo- domain

  62. 13:55

    graph and a reasoning graph which it can look into.

  63. 14:00

    And then finally, it's exposed with a user interface, which is a simple Next.js application that gives us a front end like what we'd want a, an end user or consumer to, to use for this particular use case.

  64. 14:16

    And for this application, what it does is it presents to you a prompt where you can ask it a bunch of questions. We're gonna ask it about Jessica Norris and see whether she should get an approval.

  65. 14:28

    And it's going back to the graph, and it's querying both information about her history, so it, it knows what her bank account is, it knows that she has some related margin trades.

  66. 14:38

    You can see some of the Cypher queries there that were queried through the model. And you can also see the knowledge graph that we're traversing and populating. So this is why knowledge graphs make things explainable and auditable, because now we see exactly the information which is being populated and used.

  67. 14:55

    You can see there was a previous rejection. And these are the sort of things which get, which get lost in, in disparate systems and tooling, where we don't bring all this information together in a, in a queryable, in a understandable form where we can build and pull out that knowledge.

  68. 15:12

    Now, unfortunately for Jessica, [laughs] the, the AI model recommends not giving her the loan, but it gives us the reasons, the risk factors, it gives us previous decisions which should influence this, and, um, fraud detection patterns about why this may be a big risk for our organization.

  69. 15:32

    And as a, an agent who's... Or a, a c- a user, a human who's using the system to make decisions, this is the sort of information you need to actually make a decision you can stand behind and you can justify to your organization.

  70. 15:48

    And then us as developers, now we can justify why our agentic applications are actually solving real business problems, providing grounded information that our users can rely on,

  71. 16:02

    and are taking advantage of the latest techniques with context graphs, which, um, as we know, Gartner approves of.

  72. 16:10

    All right. So let me leave you with some resources that you can use to learn more. Um, I run the DevRel team. One of our big pushes is free education, so we just wanna help people to understand how to, how to use graphs, how to use context graphs, how to use, um, AI.

  73. 16:26

    We have a new context graph course that we just released on Graph Academy. Um, also, it makes it really easy to get started because we, in the background, we spin up a free Aura instance, so you just have a graph database to play with for free.

  74. 16:39

    You can try a bunch of these techniques out before you even try it in, you know, your own production instance, your own enterprise instance.

  75. 16:47

    So, I hope you guys enjoyed the talk and learned a little bit about what the possibility with context graphs is. The next set of presenters, my, my colleagues, um, Zayd and ABK, are gonna dig a little bit more into agentic use cases of context graphs.

  76. 17:02

    And, you know, please come chat with us, either after the talk or at the Neo4j booth. We're, we're happy to have conversations, kind of dig more into demos, dig more into your use cases, and help all of us to escape the matrix.

  77. 17:17

    So, thank you very much. [audience applauding] [upbeat music]