Your Coding Agent Is 6 Months Out of Date — Jakub Hojsan, Exa
This talk introduces Exa, a semantic search engine designed to address the "knowledge cutoff" problem in large language models (LLMs) used for coding and code review agents. Exa provides highly relevant, token-efficient highlights from web pages, rather than entire documents, allowing LLMs to process information faster and more cost-effectively. The platform also offers Exa Agent for orchestrating searches across various data providers, extending beyond just web content to include private markets and media intelligence.
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Jakob Hoisan, a deployed engineer at Exa, presents on semantic search built for coding and review agents, specifically addressing the limitations of large language models (LLMs) in accessing up-to-date information. The core problem, referred to as “knowledge cutoff,” is that LLMs are trained on fixed datasets and thus lack real-time or recent information, creating a significant lag (typically around six months) between their knowledge cutoff date and current events or code changes.
For coding and code review agents, this means LLMs cannot review pull requests (PRs) or provide assistance on recent code changes or dependency bumps that occurred after their training data cutoff. A human developer would typically search platforms like Stack Overflow for error codes or package updates. In contrast, an LLM without external search capabilities would declare the information non-existent.
Exa's solution involves a semantic search engine that provides LLMs with context-rich highlights from the web. Instead of returning full webpages or long lists of links, Exa distills the most relevant information into concise snippets, often around 700 characters, to efficiently answer specific queries. This approach is token-efficient, reducing the input size for LLMs, which in turn lowers processing costs and speeds up response times without sacrificing information quality.
Key advantages of Exa for LLMs include:
1. Transparency: Exa reveals the exact sources, queries, and highlights provided to the LLM, making the information retrieval process auditable, unlike the opaque "black box" web search capabilities often built into proprietary LLMs. 2. Token-efficient highlights: Only relevant passages are passed to the LLM, preventing the need to process entire pages, which is crucial for managing context windows and computational costs. 3. Cost-effectiveness: By delivering precise, highlighted information rather than entire web pages, Exa reduces the number of tokens an LLM needs to process, leading to lower operational costs, especially for large workloads. 4. Standardization: Exa provides a consistent retrieval layer across various LLM providers (e.g., Anthropic, OpenAI), allowing developers to switch models without needing to re-engineer their search integration. This also enables models to access current information that lives outside their frozen training weights.
To effectively leverage search, an LLM agent requires a trigger mechanism—a rule for when to use the search tool. Simply providing access to a search API is insufficient, as the model may not know when to invoke it, particularly if the answer lies outside its training data. Exa addresses this by enabling agents to be configured with rules, for example, "when a diff bumps a dependency or version, then search upstream for breaking changes and ground the review in what you find."
The presentation includes a live demo showcasing Exa's capabilities within an external search playground. The demo illustrates how Exa can quickly retrieve specific information (e.g., a phone number from a personal website) or broader data (e.g., attendees and their affiliations at the AI Engineer World’s Fair) by dynamically extracting highlights from web sources. Users can specify the number of results, search type (instant, feed, auto, deep), and maximum character count for highlights.
Beyond basic web search, Exa is expanding with Exa Connect & Exa Agent. Exa Connect is designed to integrate with a growing list of data providers—including the open web, and private data sources—to surface insights from web analytics (Similarweb), media intelligence (Particle for podcast transcripts), and private markets (Crunchbase for funding and acquisitions). Exa Agent orchestrates these diverse data sources to answer complex, high-computational research queries that would otherwise require manual effort or multiple specialized tools. This allows agents to perform tasks like finding all employees of a startup or gathering comprehensive company profiles for financial firms and hedge funds. Exa emphasizes its ability to provide highly curated and relevant data through its carefully indexed documents, leading to better quality information compared to broader search engines.
Finally, Exa encourages engineers to integrate its search API into their coding agents. It supports various coding environments and LLM providers like Cursor, Claude Code, CodeX, Mindcraft, Continue, Zed, VS Code, Warp, Emu Code, Kite, and Opencode, offering flexibility and powerful external knowledge grounding for AI applications.