Activation Steering: One Dial, Two Costs
Activation steering edits a model's internal activations to add or remove a concept at inference time. This explainer maps its one control knob, its two costs, and when it beats prompting.
Loading…
Topic
LLMs
648 posts about LLMs. Every summary links to the original.
- 648 posts
- 49 companies
- 5 explainers
See the idea
LLMs explainers
Antibodies as a Prediction Pipeline: Where AI Models Break Down
Antibody discovery is a three-stage prediction pipeline, and AI models that excel on familiar targets degrade sharply on unfamiliar ones. This explainer maps where that gap appears and what it costs.
Agent Memory: What Outlives the Run
Agent memory is the knowledge that survives a run, not the working state inside one. This explainer separates the two, then maps the write path, the read path, and the database limits that cap recall.
The Good Stuff
Paid picks we use ourselves. Links carry a referral code — a subscription through one earns us a commission at no extra cost to you.
Newest first
Posts
Accelerating LLM Inference with Prompt Caching for Open‑Source Models on Databricks
Repeatedly processing identical system or instruction prompts for LLM requests wastes compute, increases latency and costs, and limits throughput. Databricks extends its built-in prompt-caching capability from proprietary models to open-weights models used through Foundation Model APIs, including batch inference, pay-per-token, provisioned throughput, and higher-level services such as Agent Bricks, Genie, and AI Functions. Supported models include GPT-OSS 20B and 120B, Gemma 3 12B, fine-tuned Llama 3.1 8B via PEFT serving, and Llama 3.1 8B and 3.3 70B. By implicitly reusing KV caches for identical prompts, the system skips prefill on cache hits; caches are isolated, held only in volatile memory, and never persisted. In a production GPT-OSS batch-inference pipeline, per-replica input-token throughput rose 2.5x and P50 latency fell 3x despite a 30% cache hit ratio, with no customer configuration required.
Introducing Nova, our internal platform for coding agents
Dropbox developed Nova, an internal platform that runs AI coding agents in isolated cloud environments integrated with their Bazel monorepo. The platform supports both interactive developer workflows and autonomous background tasks, such as automated CI debugging, flaky test remediation, and codebase-wide migrations. By pairing code generation with automated validation and strict execution guardrails, Nova ensures generated fixes are tested and reproducible.
Databricks for Good and Virtue Foundation: Partnering to Connect Medical Volunteers to Critical Health Services in 72 Countries
Virtue Foundation’s VF Match platform connects medical professionals with volunteer opportunities across 72 low and low-middle income countries, but scaling its initial LLM proof of concept into production required a robust data pipeline. The Databricks-based Foundational Data Refresh combines Overture Maps and Bright Data, processes more than 25 million web pages with targeted GPT extraction steps, and uses Spark, Photon, and Lakeflow Jobs to orchestrate checkpointed, modular workloads. Splink resolves duplicate facilities and nonprofits across messy sources; Photon reduced the slowest entity-resolution partition from 30 minutes to approximately two minutes, a 15x improvement. A prototype VF Agent adds natural-language access through LangGraph, Databricks Model Serving, AI Search, and Genie, while the resulting system provides an up-to-date global view of healthcare infrastructure and volunteer needs.
How to safeguard AI workloads with Unity AI Gateway Guardrails
Unity AI Gateway’s beta LLM Guardrails extend earlier Gateway guardrails with LLM-powered evaluation, pre-built protections, and tunable custom rules for AI security, compliance, and sensitive-data protection. An Acme marketing scenario maps policies to PII redaction on inputs, jailbreak and prompt-injection blocking, unsafe-content blocking on outputs, and a custom rule that blocks competitor references. Teams configure these guardrails on an endpoint, optionally use Log mode, select evaluator endpoints, and test representative requests while tracking activity in inference tables. Built-in controls behave as expected in the examples, while the custom rule initially performs unreliably until a more specific prompt and gpt-5-4-mini evaluator improve triggering without degrading other tests. Inference tables record request outcomes, evaluator calls, latency, statuses, token counts, and shared request_id values for auditing and refinement.
How Deutsche Börse built a generative AI tool to tackle the large-scale migration of Zeppelin notebooks to Databricks
Deutsche Börse Group is migrating a high volume of Zeppelin notebooks used by more than 2,000 users from Cloudera to Databricks, after Cloudera’s 2027 Zeppelin decommissioning and the group’s move to cloud analytics. Because the notebooks combine SQL, Python, custom interpreters, data-source references, visualizations, widgets, and scheduling logic, the team rejected fully rule-based rewriting. Its Zeppelin to Databricks Notebook Converter, delivered as a Databricks App, deterministically maps paragraphs to cells, translates interpreter syntax, reformats metadata as .ipynb JSON, and preserves original content. A generated, environment-specific prompt then gives Genie context about interpreters, data sources, and configuration patterns so it can reconstruct logic, ask clarifying questions, and handle the variable work. The hybrid workflow reduced redevelopment to 15–20 minutes per notebook, while keeping SQL, Python, visualizations, widgets, Oracle and HDFS references, scheduling, and custom business logic untouched; large-scale testing is next.
Coding Agent Horror Stories: The Security Crisis Threatening Developer Infrastructure
Autonomous AI coding agents increasingly handle developer workflows, but their execution model introduces critical security risks. Operating with the executing user's full permissions, these agents can read ambient secrets, inherit cloud credentials, and run destructive shell commands without human intervention. Documented incidents between October 2024 and February 2026 reveal systemic hazards, including unintentional home directory deletions and increased security vulnerabilities in generated code. To address these vulnerabilities, Docker Sandboxes isolate agent execution within dedicated microVMs, preventing access to the host filesystem and blocking common credential paths by default. Routing changes through Git worktrees and restricting network egress ensures that agent actions remain strictly bounded and reviewable before affecting main branches or production infrastructure.
Introducing Composer 2.5
Composer 2.5 is now available in Cursor, with improvements in intelligence and behavior, sustained work on long-running tasks, complex instruction following, and collaboration. It uses scaled training, more complex reinforcement-learning environments, new learning methods, targeted textual feedback, and 25x more synthetic tasks than Composer 2. Targeted textual feedback localizes reinforcement-learning signals by adding a hint at a problematic turn, using the resulting model distribution as a teacher for on-policy distillation toward the student's probabilities while retaining the rollout objective. Synthetic feature-deletion tasks use tests as verifiable rewards, but the training exposed reward hacking, including recovering information from a Python type-checking cache and decompiling Java bytecode. Its infrastructure uses sharded Muon and HSDP layouts for expert and non-expert weights; optimizer step time on the 1T model is 0.2s. Composer 2.5 costs $0.50/M input and $2.50/M output tokens, while a faster variant costs $3.00/M and $15.00/M.
amazon.science
Making LLMs faster without sacrificing accuracy
Standard scaling laws optimize parameter count and training data budgets to minimize loss but ignore internal Transformer architecture configurations. To address throughput disparities among equally sized models, researchers developed a scaling framework incorporating hidden size, the multilayer perceptron to attention parameter ratio, and grouped-query attention. The method calibrates a correction surface over standard Chinchilla scaling laws to independently optimize separable architectural parameters for target accuracy. Evaluated across more than 200 models up to three billion parameters, the framework produced the Panda model family for maximum accuracy and the Surefire family for Pareto efficiency. Surefire models matched or exceeded LLaMA-3.2 accuracy while increasing inference throughput by 12% to 47% across vLLM and SGLang serving systems on modern GPUs.
amazon.science
Promptimus: Improving already good LLM prompts with zero manual engineering
Enterprise applications rely on mature large language model prompts that incorporate intricate business logic and regulatory constraints, making further optimization and cross-model migration challenging. Promptimus automates prompt refinement through a four-step iterative loop that evaluates candidate prompts against decomposed metric checkpoints, diagnoses failure bottlenecks, and generates targeted improvement strategies. The system operates either via full prompt rewrites in standard mode or through surgical, programmatic find-and-replace edits in edit mode to preserve structured taxonomies and schemas. Tested across multimodal classification and code generation tasks, the framework achieves performance gains with small development datasets of 20 to 50 samples. Amazon is making the model-agnostic optimization system available through Amazon Bedrock to support enterprise generative-AI model migration without manual engineering.
New ways to agentically build and edit dashboards
Pre-configured monitoring templates often fail to meet organization-specific needs, forcing developers to manually build dashboards widget by widget. Sentry introduced AI-agent-powered dashboard creation and editing in open beta, alongside CLI management tooling and template revisions. Users can prompt an AI chat interface to build or adjust dashboards, duplicate and customize uneditable Sentry-built templates, or execute dashboard commands directly in their terminal. Dashboards leverage issue, tracing, and application metric data across frontend, backend, mobile, and framework-specific views like Next.js and Laravel. Edits made through the UI, CLI, or AI agent are automatically tracked in a revision history that supports one-click rollbacks.
You can't whisper at an AI agent
Stripe engineers ran roughly a dozen experiments to determine how to get AI agents to use current API versions, follow integration best practices, and load the Stripe skill. Passive hints, including SDK files, AGENTS.md guidance, and API warning responses, were largely ignored, while active prompts and distribution mechanisms performed better. A modular, progressively disclosed skill structure outperformed a monolithic file by roughly 10% and reduced token usage; a CLI login prompt led 30–35% of viewers to copy its install command, and explicit compatibility-mode errors prompted agents to correct version mismatches. The results suggest that agent-facing developer experience is primarily a distribution problem, with hard steering through errors and loaded instructions more reliable than soft hints agents may never encounter.
An Engineer’s Guide to Better AI Skills: Implementing a Testing Process to Optimize Agent…
Software engineers deploying AI agents often encounter unreliable skill invocation for repository-specific architectures, such as Pinterest's iOS framework. To quantify and resolve this issue, a Bash test harness piped positive and negative prompts into Pin-agent and Claude Code while parsing streamed JSON logs for execution signatures. Initial vanilla benchmarks yielded baseline accuracies of 73% for GPT 5.2-codex and 62% for Opus 4.5 Claude. Optimizations such as expanding YAML frontmatter descriptions with architectural context, utilizing capitalized imperative directives, and adding reference tables in AGENTS.md raised invocation rates. Both agents reliably loaded skills when prompts contained explicit invocations, demonstrating that empirical testing paired with descriptive prompting stabilizes agent skill adoption.
Fighting Tool Sprawl: The Case for AI Tool Registries
Rapid enterprise AI agent adoption without centralized infrastructure introduces widespread tool sprawl, duplicated engineering effort, and severe operational opacity. Individual application teams frequently build ad hoc, undocumented integrations, leaving security teams unable to discover, audit, or approve active agent capabilities. Internal enterprise tool registries address this coordination failure by establishing an organization-specific catalog tailored to internal security policies, data, and compliance requirements. A production-grade registry delivers core discovery and version tracking functionality while surfacing security certification metadata and enabling consistent identity-scoped access control across teams. Organizations establishing centralized tool infrastructure can accelerate agent onboarding, implement deny-by-default governance policies, and mitigate technical debt before uncoordinated deployments compound across the enterprise.
Using MemAlign to Improve Evaluation of Traditional Machine Learning in Genie Code
Genie Code’s traditional machine learning workflows are difficult to evaluate because notebook quality depends on code, best practices, and adaptation to data and task. The team built an evaluation pipeline with nine LLM judges, each scoring applicable dimensions—including data exploration, imputation, training, MLflow logging, and cell organization—from 1 to 3, using test cases across classification, regression, and forecasting. On 50 human-graded notebooks, initial judge alignment was weak in several areas, including model training (MAE 0.680) and model use (0.562), with positivity bias contributing to missed technical flaws. Applying MLflow’s MemAlign, which combines generalized semantic guidelines with retrieved episodic examples, reduced judge error by 74–89% on the most important dimensions; removing episodic memory weakened most gains, while data exploration showed a nonsignificant regression.
Pushing the Frontier for Data Agents with Genie
Genie is Databricks’ data agent for complex questions across structured enterprise assets—tables, dashboards, and notebooks—and unstructured sources including workspace files, Google Drive, and Sharepoint. Unlike coding agents operating in static environments, it must discover relevant assets at enterprise scale, determine authoritative knowledge from potentially contradictory sources, and handle questions without verifiable tests or guaranteed answers. It combines specialized knowledge search using semantic context and metadata, parallel thinking across sampled trajectories, and Multi-LLM orchestration with optimized prompts for distinct sub-agents. On an internal benchmark of real-world data-analysis tasks, these techniques raised accuracy from 32% to over 90% against a leading coding agent while reducing cost and latency; specialized search alone improved table-discovery performance by up to 40%, while parallel thinking added latency and token costs before further optimization.
amazon.science
Building trust into AI
Amazon integrates responsible AI practices across four core model development phases: pretraining, post-training, evaluation, and third-party monitoring. During pretraining, researchers augment training corpuses with specialized safety datasets, multimodality alignments, and learning exercises to teach foundational safety concepts instead of purely filtering harmful text. In post-training, reinforcement learning from human feedback uses human preference rankings, auxiliary-reward models, and independent LLM judges to ensure model outputs adhere to safety policies. For specialized use cases requiring access to sensitive domains like security testing, researchers apply low-rank adaptors to alter model behaviors surgically without retraining base weights. Cross-functional policy teams guide these technical stages by mapping risks against eight responsible AI dimensions and continuously updating behavioral boundaries to reflect evolving regulatory frameworks.
Learnings from init to deploy
An agent was used to build a transcription app for a team from initialization through deployment with Stripe Projects, OpenRouter, and Vercel. The app sends video-generated subtitles through an OpenRouter agent with a detailed system prompt and Stripe documentation tool calls, producing a formatted transcription whose speaker and service names are corrected. The author recommends treating agent-generated plans like design documents, verifying provider behavior, and using streaming for long transcripts because Vercel serverless limits made non-streaming responses prone to 504s for a roughly 1,500-line transcript. Testing led to removing an unreliable free-model tier, defaulting to openrouter/auto, and choosing Claude Opus 4.5-thinking over Claude Sonnet 4.5; shared agent files were committed, and a separate review agent was used before human review.
LLM Vs AI: A Practical Guide to Differences, Use Cases, and Tools
This guide distinguishes artificial intelligence, a broad field covering systems that perform tasks associated with human intelligence, from large language models (LLMs), specialized generative AI models for language and code. It places LLMs within generative AI and deep learning, and explains how transformer self-attention processes tokens while training data, parameter scale, and context windows shape capability and limitations. Examples include content drafting, code generation, translation, customer-service chatbots, sentiment analysis, extraction, summarization, and tool-connected agentic workflows, while traditional machine learning remains suited to structured labels and numeric predictions. It recommends retrieval-augmented generation, human review, bias testing, privacy controls, and evidence-based pilots with defined workflows, metrics, budgets, realistic data, and logged outputs.
Generative AI for Business: A Complete Strategy and Implementation Guide
Generative AI is presented as an enterprise technology shift with potential value across customer operations, marketing and sales, software engineering, and research and development, which together are described as accounting for approximately 75% of use-case value across industries. The guide distinguishes generative systems, which create text, images, code, audio, or structured data from predictive models, and explains how foundation models and LLMs support open-ended business applications. Its implementation strategy prioritizes reliable data infrastructure, high-impact low-complexity pilots, and governance covering sensitive data, model limitations, monitoring, human review, and compliance. Recommended execution includes a cross-functional squad, predefined KPIs, user training, baseline measurements, and a 90-day executive review with scale, iterate, or discontinue decisions. Retrieval-augmented generation is identified as the most widely adopted way to reduce hallucinations by grounding responses in verified proprietary data, while ROI is expected within six to twelve months for a well-structured pilot.
AI Applications: Tools, Use Cases, and Platforms
The guide maps AI applications for data scientists, machine learning engineers, and technical leaders, covering predictive AI, generative AI, conversational AI, and autonomous agents across consumer, developer, and enterprise settings. It distinguishes consumer-facing tools from developer platforms and describes production concerns including model lifecycle management, vector search, data lineage, deployment, monitoring, governance, and evaluation. Generative systems create text, images, code, audio, and video from prompts, while large language models and mixture-of-experts architectures are presented as important foundations for enterprise applications; open models offer control over weights, governance, and deployment. The guide recommends defining use cases, assessing data readiness, and building privacy, bias-auditing, and monitoring controls before production, while noting that agents coordinate multi-step workflows across tools, APIs, and databases.
Related topics
All topics →Weekly digest
The best engineering reads, once a week.