The library

A growing field-guide library. One operating method.

Each book owns a distinct production problem, and every supporting guide leads back to one clear system boundary.

Cover of AI Agent Platform Engineering by Leo J. Li

Signal Studio field guide

AI Agent Platform Engineering

From Prototype to Production: Orchestration, State, Queues, Retries, Identity, Deployment, and Operations

A production engineering method for agent services, connecting execution contracts, deployment revisions, operational controls, human takeover, tenancy, and capacity.

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Cover of AI Agents for SRE by Leo J. Li

Signal Studio field guide

AI Agents for SRE

Building LLM Root Cause Analysis on OpenTelemetry Traces, Logs, and Metrics

A field guide to building SRE agents that investigate incidents through explicit evidence, falsifiable hypotheses, bounded authority, and replayable evaluations.

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Cover of AI Cost Engineering by Leo J. Li

Signal Studio field guide

AI Cost Engineering

Token Economics, Model Routing, Caching, Capacity, and Cost per Outcome

An engineering guide to measuring and controlling the full cost of useful AI outcomes across requests, retries, tools, reviews, routing, caching, and capacity.

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Cover of AIOps in Production by Leo J. Li

Signal Studio field guide

AIOps in Production

From Intelligent Thresholds to Graph Reasoning and Reliable Automation

An operating guide to alert quality, incident grouping, capacity forecasts, operational graphs, diagnosis, and bounded recovery automation.

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Cover of Build Your First App with AI by Leo J. Li

Signal Studio field guide

Build Your First App with AI

A Step-by-Step Guide for People Who Have Never Written Code

A beginner path from a first web page to an AI-built app, with recoverable data, checkable changes, and deliberate release decisions.

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Cover of ClickHouse Observability at Scale by Leo J. Li

Signal Studio field guide

ClickHouse Observability at Scale

Build a Unified OpenTelemetry Platform for Logs, Metrics, and a Million Spans per Second

Design OpenTelemetry and ClickHouse observability around signal meaning, ingestion, query performance, replay, and operating limits.

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Cover of Context Engineering in Production by Leo J. Li

Signal Studio field guide

Context Engineering in Production

Designing Memory, Retrieval, State, Provenance, and Long-Running Agent Workflows

A systems guide to trustworthy working context, governed memory, durable state, provenance, retrieval, and side effects across long-running agent workflows.

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Cover of Engineering Judgment in the Age of AI by Leo J. Li

Signal Studio field guide

Engineering Judgment in the Age of AI

From Writing Code to Making Tradeoffs: A Practical Guide to Questions, Verification, and Failure Drills for Early-Career Developers

A practical guide for developers who want AI-assisted speed without surrendering problem framing, constraints, verification, failure reasoning, and durable learning.

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Cover of Evaluating AI Agents by Leo J. Li

Signal Studio field guide

Evaluating AI Agents

From Golden Datasets and Trace Grading to Simulation, Red Teaming, and Production Quality Gates

A measurement guide to agent outcomes, trajectories, permissions, budgets, stochastic reliability, and serious failures in controlled and production environments.

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Cover of EvoOntology in Practice by Leo J. Li

Signal Studio field guide

EvoOntology in Practice

Building and Evaluating Self-Evolving Semantic Layers for Data Agents

Build an inspectable semantic layer for data agents and evaluate bounded changes to definitions before they affect business answers.

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Cover of From the Field to the Product by Leo J. Li

Signal Studio field guide

From the Field to the Product

How Forward Deployed Engineering Turns Real-World Problems into Scalable Products

A field guide to forward deployed engineering as an accountable loop from operational problems to production outcomes, reusable products, and customer independence.

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Cover of Generative Engine Optimization by Leo J. Li

Signal Studio field guide

Generative Engine Optimization

From Search Rankings to Accurate Discovery, Understanding, and Citation by AI

An evidence-first guide to technical content across discovery, retrieval, understanding, citation, and post-answer behavior—without replacing sound SEO with GEO folklore.

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Cover of LLM-as-a-Judge in Practice by Leo J. Li

Signal Studio field guide

LLM-as-a-Judge in Practice

A Complete Guide to Expert-Led Evaluation

Design and maintain a task-specific language-model judge with expert reference decisions, error measurement, stress tests, and auditable recalibration.

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Cover of MCP in Production by Leo J. Li

Signal Studio field guide

MCP in Production

Security, Observability, Versioning, and Governance for Agent Tooling

Operate production MCP tools with catalog identity, authorization, service objectives, compatibility, releases, admission, and remote-provider controls.

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Cover of Observability for AI Agents by Leo J. Li

Signal Studio field guide

Observability for AI Agents

Tracing Models, Tools, Memory, and Multi-Agent Workflows with OpenTelemetry

A vendor-neutral guide to observing agent runs across models, retrieval, tools, memory, handoffs, state, effects, evaluations, cost, privacy, and human review.

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Cover of Ontology-Driven Forward Deployed Engineering by Leo J. Li

Signal Studio field guide

Ontology-Driven Forward Deployed Engineering

An Enterprise Architecture for Turning Domain Meaning into Governed Operational Systems

Connect business meaning to governed action through decision discovery, a semantic kernel, source mappings, evidence, delivery slices, semantic change, and product reuse.

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Cover of Securing AI Agents by Leo J. Li

Signal Studio field guide

Securing AI Agents

Prompt Injection, Tool Permissions, Identity, Sandboxing, Memory Poisoning, and Audit Trails

A control-oriented guide to prompt injection and excessive agency through permissions, identity, sandboxing, governed memory, mediated effects, and audit trails.

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Cover of Skills in Production by Leo J. Li

Signal Studio field guide

Skills in Production

Designing Governed, Secure, and Self-Evolving Agent Capabilities

A production method for reusable agent skills: capability boundaries, discovery, package identity, release evidence, coexistence, and controlled improvement.

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Cover of Why Systems Fail by Leo J. Li

Signal Studio field guide

Why Systems Fail

From Ontology Modeling, Observability, and CMDB to AI-Agent Root Cause Investigation

A systems guide to building operational semantics across ontology, CMDB, telemetry, provenance, topology, change, and AI-assisted root cause investigation.

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