Agentic vs. Vector Search: An Eval-Driven Approach to Coding Agent Performance

Agentic vs. Vector Search: An Eval-Driven Approach to Coding Agent Performance

🎙 Jessica Wang 👥 5K 📅 August 11, 2026 ⏱ 29 min 👁 5 📄 expert opinion 🧭 2026-08-15
Available in: English (current) Français

Keywords

evalsagentic searchvector searchcoding agentsBraintrust

Summary

The talk by Jessica Wang, a DevRel engineer at Braintrust, introduces the concept of AI evals as a way to replace subjective ‘vibes’ with quantifiable decisions. She explains the four core components of an eval: datasets, tasks, scoring, and experiments. To illustrate, she presents a real-world eval comparing agentic search (as used by Claude Code) and vector search for coding agents. The methodology involves creating datasets from the TypeScript Go repository and SWE-bench, synthesizing bug tickets, and using Claude Code as the harness. Vector search was implemented with restrictions to prevent fallback to agentic search. Results show similar accuracy (~70%) but significantly higher token and cost usage for vector search. Analysis of traces revealed that vector search returned many chunks but lacked the ‘connective tissue’ to implement fixes, leading to more calls. The speaker discusses limitations, including small datasets and non-determinism, and suggests improvements such as multiple trials and hybrid approaches. She emphasizes that evals are a team sport and iterative process.

162 words

Critical Evaluation

Value of the Information & Strength of the Argument

The talk provides a valuable, practical introduction to AI evals, with a concrete example that demonstrates the process. The argumentation is clear and logical, building from basic concepts to a real-world application. The speaker is transparent about the limitations of her eval, which enhances credibility. However, the conclusions are based on a small sample size and a single run, so they should be interpreted with caution. The comparison between agentic and vector search is insightful, highlighting efficiency differences, but the speaker acknowledges that her vector search implementation was basic, which could affect the results.

Scientific Rigor, Source Quality, Title Accuracy

The talk is scientifically rigorous in its approach, with a clear methodology and acknowledgment of limitations. The speaker cites the Cursor article as motivation and uses SWE-bench as a benchmark, but no external sources are provided in the description. The title accurately reflects the content. The talk is based on the speaker’s own work and experience, which adds authenticity but also means it is not peer-reviewed. The small dataset sizes and single-run results limit the generalizability of the findings.

188 words

Title / Content Match

The title accurately reflects the content, which focuses on comparing agentic and vector search for coding agents using an eval-driven approach.

Quality & Reliability

7/10

The talk is based on a real-world eval conducted by the speaker, with clear methodology and transparent limitations. However, the sample sizes are small (10 and 25 test cases), and the results are not peer-reviewed. The speaker openly acknowledges the preliminary nature of the findings.

Key Moments

Cited Sources

  • Cursor article on agentic search — Mentioned as motivation for the eval, but no URL provided
  • SWE-bench — Used as a source for the second dataset (Django rows)

Concurring Sources

  • SWE-bench — Used as a benchmark for coding agents, consistent with the talk's methodology.

Contribution & Novelties

The talk provides a practical, step-by-step guide to building an eval for comparing search strategies in coding agents. It offers a real-world example with concrete results and insights, such as the efficiency difference between agentic and vector search. The speaker also shares technical challenges and solutions, like tracing subprocess calls. This is valuable for practitioners looking to implement evals in their own workflows.

Pour aller plus loin :

  • SWE-bench — The industry standard benchmark for coding agent performance, used in the talk.
  • Braintrust — The platform used for evals and observability, mentioned throughout.
  • Claude Code — The agentic coding tool used in the eval, which uses agentic search by default.

110 words

Radar Profile

The radar profile shows a balanced performance across all dimensions, with slightly lower scores in 'fiabilite_globale' due to the preliminary nature of the results. The talk is strong in providing valuable information and clear argumentation, but the small sample size and lack of peer review temper the overall reliability.

Reliability 6/10

💬 No comments were provided for analysis.