The Twenty Minute VC (20VC): Venture Capital | Startup Funding | The Pitch
Hosted by Harry Stebbings
Written by a model from the transcript; not yet reviewed.
This episode features a conversation with Harrison, the founder of LangChain, exploring the complexities of building AI agents, the evolving infrastructure stack, and the economics of inference and coding tools. The guest explains why non-deterministic models cause cascading errors in agent systems, how businesses must regularly erase parts of their product as foundational models improve, and why the guest believes model routing belongs primarily at the harness layer rather than the gateway layer for vertical applications. They also discuss the true cost of engineering tools, the future of agent memory, and what makes top-tier venture capital firms like Sequoia and Benchmark invaluable partners for early-stage founders.
Throughout the discussion, the guest shares specific metrics from running LangChain, noting that engineering teams spend roughly 30% of their salary on coding tools and detailing how implementing visibility, basic cost controls, and custom cloud harnesses helped bring those expenses under control. They also analyze the state of open-source versus proprietary models, the limitations of current agent memory solutions, and why vertical agents will ultimately interact through standardized natural language interfaces. The conversation offers a candid look at the realities of technical execution and startup scaling in a rapidly moving market.
The host introduces the episode, mentions the guest and sets the stage for a discussion on agents and inference markets.
A detailed explanation of Fireworks, its Nexus platform, and how intelligent model routing optimizes AI workloads.
Discussion on the role of evals and traces in improving agents, the mechanics of continual learning, and how insights loop back into context, harness, and model layers.
Exploration of how agent systems must adapt as models improve, the concept of erasing product layers, and the importance of neutral harnesses for portability.
A deep dive into where model routing should reside, the trade-offs between harness-level and gateway-level routing, and the impact on vertical versus horizontal agents.
Insights into the early state of memory systems for agents, the need for domain-specific solutions, and the anticipated widespread adoption of memory layers in future products.
Examination of how agent workloads strain infrastructure, the evolving cost of tokens, and strategies for cost control and efficiency in coding and other agent use cases.
A survey of enterprise concerns, highlighting accuracy as the top priority, followed by latency, cost, and security, and how these factors influence agent design.
The team discusses a costly plugin misuse that led to a $40K expense, highlighting the need for better monitoring.
They project that coding agent spend could match or exceed human salaries as organizations shrink and become more efficient.
Why Building Agents Is Hardinsight
The guest explains that agents are non-deterministic black boxes operating in infinite input and output spaces, making it difficult to prevent cascading system errors.
Erasing Products As Models Improvestrategy
As foundation models improve every few months, developer tool companies must be willing to delete large parts of their product that are no longer necessary.
Harness Versus Gateway Model Routingdebate
The guest argues that smart routing belongs at the harness layer because it has awareness of prompt caching and operational state, unlike API gateways.
Automating Harness Updates With Tracesstrategy
LangChain uses an internal agent called Engine to run over agent traces and automatically update the code of the harness itself.
Killing Commercial Memory Solutionsstory
The guest reveals that LangChain launched and later killed a commercial memory product because it was too general and failed to find product-market fit.
Engineering Salary Spent On Toolsdata
The guest shares that LangChain spends roughly 30% of its engineering salary on coding tools, though total token usage and costs fluctuate.
“We spend probably roughly 30% of our engineering salary on coding tools.”
“The hard part about building agents is they don't behave how you want them to behave.”
“If value is derived through verification, I think the people who win are the domain experts.”
“I think the fact that memory will have an impact is quite obvious, and that's where you see so many people interested in it.”
“Another thing would be latency, by the way. We run developer surveys every year where we ask developers what they care about.”
“I think the tricky part is that the only place we've seen agents really have effect is in software engineering so far, though, and there are a ton of other places within an enterprise that I would argue have yet to kind of be affected by agents.”
“I think in the next 12 months, we will absolutely have comparable US open-source models.”
“I wish I knew what harnesses today looked like so we could have built them earlier.”
“I think we should have inference and then like infrastructure, so like low level infrastructure, Temporal, Modal, Superbase, Convex.”
Harrison Chase is the co-founder and CEO of LangChain, which helps developers build, test and deploy AI agents. Backed by Sequoia Capital, Benchmark and IVP, LangChain has announced approximately $160 million in funding with the last round at a $1.25BN valuation. The company works with 35% of the Fortune 500, has surpassed one billion open-source downloads and processes over one billion events daily through LangSmith. AGENDA: 04:10 Why Is It Still So Hard to Build AI Agents? 08:50 Will the Model Labs Eat the Agent Stack? 16:25 Is Model Routing a Real Business or a Commodity? 25:45 Why Has No One Solved AI Memory? 35:45 Why Are AI Bills Exploding as Tokens Get Cheaper? 43:25 Should Companies Be Afraid of Chinese AI Models? 46:20 Where Would Harrison Not Be Investing Today? 53:05 Should Founders Take a Discount for Benchmark and Sequoia? 57:35 OpenAI at $1.5T or Anthropic at $2T: Which Would You Buy?
13,554 words · 2 speakers
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