Engineering notes
Since 2023 we have documented what actually works in AI systems — with numbers, sources and honest limits.
Copilot Studio entered 2026 with four production-relevant capabilities: model choice including Anthropic's Claude models, computer-use automation in preview, generally available MCP integration, and agent evaluations. We examine what each capability shipped, what remains preview-only, and why low-code agents now clear the bar for production use — with dates, limits, and open questions.
Microsoft Agent Framework merges Semantic Kernel and AutoGen into one open-source agent stack for .NET and Python. Both predecessors are in maintenance mode. We summarize the timeline and the API changes, then give a migration playbook and a parity-testing approach that catches behavioral drift before cutover — as of January 2026, with GA expected within months.
Agentic systems end their journeys at systems other people operate: authorities, banks, partner APIs. We define simulated counterparts that implement the identical agent contract, show how end-to-end journey tests run against them before go-live, and argue for strict provenance labeling — a simulated pass proves logic, never production readiness. Verified dates, honest limits included.
A2A is approaching its first production-ready release. We trace the protocol from Google's April 2025 announcement to the v1.0 Release Candidate: signed Agent Cards, the task lifecycle, multi-tenancy, and the JSON-RPC and gRPC bindings. Plus concrete guidance on what to build on v0.3.0 today and which wire-format changes to isolate before 1.0 lands.
A retrospective on 2025 as the protocol year: MCP became the cross-vendor interface for tools, Google donated A2A to the Linux Foundation, DeepSeek-R1 and Apache-2.0 releases commoditized reasoning, and coding agents reached production. We review the verified milestones and outline what 2026 must solve: agent identity, evaluation infrastructure, and simulation.
Subagent and peer agent name two different architectures, not two words for one. We derive the distinction from first principles — who owns the context, who owns the lifecycle — and show how trust boundaries, token cost, and testability follow, with measured numbers from Anthropic's multi-agent research system and the A2A protocol as of December 2025.
On December 9, 2025 the Linux Foundation announced the Agentic AI Foundation, co-founded by Anthropic, Block and OpenAI. Anthropic donated the Model Context Protocol, Block contributed goose, OpenAI added AGENTS.md. We examine what neutral governance changes for the agentic stack, what it deliberately leaves unsolved, and what engineering teams should do now.
Microsoft Agent Framework entered public preview on October 1, 2025, converging Semantic Kernel and AutoGen into one SDK. Both predecessors are now in maintenance mode. We summarize the verified facts, map the .NET programming model changes, and outline a migration sequence that avoids maintenance-mode debt before the framework reaches general availability in 2026.
LangChain 1.0 and LangGraph 1.0 shipped on 22 October 2025 with a no-breaking-changes commitment until 2.0. We examine create_agent and its middleware hooks, checkpointer-backed persistence, human-in-the-loop interrupts, and the mechanics of migrating legacy chains to langchain-classic — including what the stable APIs do not solve.
Agents that run for hours or days cannot keep their state in process memory. We define durable execution, compare event-history replay with checkpoint snapshots, survey the late-2025 engine landscape from Temporal to LangGraph 1.0 and Microsoft Agent Framework, and state plainly what durability does not solve: side effects, decision quality, and context growth.
OpenAI's DevDay on 6 October 2025 introduced AgentKit — a visual Agent Builder, the embeddable ChatKit UI, extended Evals and a Connector Registry — plus apps that run inside ChatGPT via an MCP-based Apps SDK. We summarize what shipped, what is beta, where lock-in sits, and how agent teams should frame the build-vs-buy decision.
Ahead of Microsoft Ignite 2025 in November we take stock of Azure AI Foundry: what the Agent Service as a hosted runtime delivers since its May GA, what the agent factory narrative signals, why the Azure prefix is eroding, and which capabilities engineering teams should adopt now versus merely watch.