DEV Community: Rohit Raj

Kimi K2.7-Code vs Claude Opus 4.8 and GPT-5.5: Is the 1T Open Coding Model Worth It? (2026)

Rohit Raj — Sun, 14 Jun 2026 08:26:48 +0000

Moonshot AI dropped Kimi K2.7-Code on June 12, 2026 — a 1T-parameter open-weight coding model that costs $0.95/$4.00 per million tokens, roughly 5-7x cheaper than Claude Opus 4.8 and GPT-5.5. Here is the developer read: the real benchmark numbers (and why they are all first-party), a verified cost-per-task comparison the hype guides skip, how to run it via API or locally, and when you should still reach for Claude or GPT.

Read the full version with code samples, diagrams, and architecture details: Kimi K2.7-Code vs Claude Opus 4.8 and GPT-5.5: Is the 1T Open Coding Model Worth It? (2026)

More engineering notes: rohitraj.tech/en/notes

AI Agent Payments in 2026: x402 vs AP2 — How to Let Your Agent Actually Pay

Rohit Raj — Sat, 13 Jun 2026 06:03:34 +0000

x402 crossed 161M cumulative payments and got picked up by AWS Bedrock AgentCore in May 2026, while Google’s AP2 defines the trust layer above it. Here is the developer read: how x402 and AP2 actually work, working code to monetize an MCP server or API per request, the per-request settlement trap, and when to skip crypto rails entirely.

Read the full version with code samples, diagrams, and architecture details: AI Agent Payments in 2026: x402 vs AP2 — How to Let Your Agent Actually Pay

More engineering notes: rohitraj.tech/en/notes

OpenCode vs Claude Code vs Cursor: The Best AI Coding Agent in 2026?

Rohit Raj — Fri, 12 Jun 2026 05:23:47 +0000

OpenCode just became the most-starred AI coding agent on GitHub — 172,198 stars under MIT, with v1.17.4 shipping June 12, 2026. Here is the developer read: how the free, model-agnostic OpenCode compares to Claude Code and Cursor, the Terminal-Bench numbers, the BYOK cost math, and when each one is the right call.

Read the full version with code samples, diagrams, and architecture details: OpenCode vs Claude Code vs Cursor: The Best AI Coding Agent in 2026?

More engineering notes: rohitraj.tech/en/notes

How to Run DiffusionGemma Locally: A vLLM Serving Guide for RTX 5090 and H100 (2026)

Rohit Raj — Thu, 11 Jun 2026 17:08:00 +0000

A build-focused guide to self-hosting Google\'s DiffusionGemma: the exact vLLM serve command, what each diffusion flag does, how to call it like an OpenAI endpoint, and how to tune the speed-vs-quality trade-off on an RTX 5090 or H100.

Read the full version with code samples, diagrams, and architecture details: How to Run DiffusionGemma Locally: A vLLM Serving Guide for RTX 5090 and H100 (2026)

More engineering notes: rohitraj.tech/en/notes

DiffusionGemma: Text Diffusion LLMs Explained, and When to Actually Use One (2026)

Rohit Raj — Thu, 11 Jun 2026 03:09:32 +0000

Google open-sourced DiffusionGemma on June 10, 2026 — a 26B MoE that writes a 256-token block in parallel instead of one token at a time, hitting 700+ tokens/sec on an RTX 5090 and up to 4x faster than Gemma 4. The catch: quality sits below standard Gemma 4. Here is the developer read — how text diffusion works, how to run it locally, the speed-vs-quality decision, and when to skip it.

Read the full version with code samples, diagrams, and architecture details: DiffusionGemma: Text Diffusion LLMs Explained, and When to Actually Use One (2026)

More engineering notes: rohitraj.tech/en/notes

Claude Fable 5: Pricing, the API, and When to Use It vs Opus 4.8 (2026)

Rohit Raj — Wed, 10 Jun 2026 04:38:38 +0000

Anthropic shipped Claude Fable 5 on June 9, 2026 — a Mythos-class model at $10/$50 per million tokens, double the Opus 4.8 rate. Here is the developer read: the claude-fable-5 API, the Opus-4.8 safeguard fallback you must design around, the new 30-day retention rule, Fable vs Mythos, and when to wait.

Read the full version with code samples, diagrams, and architecture details: Claude Fable 5: Pricing, the API, and When to Use It vs Opus 4.8 (2026)

More engineering notes: rohitraj.tech/en/notes

This Week in AI Dev: Codex Builds Apps, the Open-Weight Frontier Explodes, and Anthropic Meters the Agent SDK (Week 24 of 2026)

Rohit Raj — Tue, 09 Jun 2026 03:48:44 +0000

Week 24 of 2026 in AI dev tools: OpenAI's Codex graduates from coding agent to app builder with Sites and role plugins, three open-weight models drop in 72 hours (MiniMax M3, Gemma 4 12B, NVIDIA Nemotron 3 Ultra), Anthropic moves the Agent SDK to metered billing on June 15, Microsoft Build hardens agent security, and the Gemini CLI consumer sunset hits June 18.

Read the full version with code samples, diagrams, and architecture details: This Week in AI Dev: Codex Builds Apps, the Open-Weight Frontier Explodes, and Anthropic Meters the Agent SDK (Week 24 of 2026)

More engineering notes: rohitraj.tech/en/notes

What Is Harness Engineering? OpenAI’s Agent-First Codex Playbook (2026)

Rohit Raj — Mon, 08 Jun 2026 04:36:57 +0000

Harness engineering is the discipline of building the scaffolding — docs, golden rules, custom linters, and agent-to-agent review loops — that lets AI coding agents ship reliable software at scale. OpenAI coined the term after building a ~1M-line beta product in 5 months with zero hand-written code using Codex. Here is what a harness actually contains, the architecture that makes it work, when it pays off, when to skip it, and how I run a smaller version of it today.

Read the full version with code samples, diagrams, and architecture details: What Is Harness Engineering? OpenAI’s Agent-First Codex Playbook (2026)

More engineering notes: rohitraj.tech/en/notes

NVIDIA RTX Spark + Windows: What Microsoft’s Local-AI Superchip Means for Developers (2026)

Rohit Raj — Sun, 07 Jun 2026 07:54:39 +0000

NVIDIA and Microsoft unveiled the RTX Spark superchip at Computex 2026 — a 20-core Grace Arm CPU plus a 6,144-core Blackwell RTX GPU and up to 128GB unified memory that runs 120B-parameter LLMs locally with up to 1M tokens of context. Here is the developer-only read: the confirmed specs, RTX Spark vs DGX Spark, how it ties into Satya Nadella’s agentic-AI push at Build 2026, what you can actually build on it this fall, and when to wait.

Read the full version with code samples, diagrams, and architecture details: NVIDIA RTX Spark + Windows: What Microsoft’s Local-AI Superchip Means for Developers (2026)

More engineering notes: rohitraj.tech/en/notes

Open Notebook vs Khoj vs SurfSense: Best Self-Hosted NotebookLM Alternative (2026)

Rohit Raj — Sun, 07 Jun 2026 03:51:49 +0000

Open Notebook just hit #1 on GitHub Trending — but is it the best self-hosted NotebookLM alternative? Here's how Open Notebook (MIT), Khoj (AGPL-3.0), and SurfSense (Apache-2.0) actually compare on Docker setup, RAG architecture, integrations, and the open-source license trap that can bite a commercial build.

Read the full version with code samples, diagrams, and architecture details: Open Notebook vs Khoj vs SurfSense: Best Self-Hosted NotebookLM Alternative (2026)

More engineering notes: rohitraj.tech/en/notes

AI Agent Memory in 2026: Mem0 vs Zep vs Letta vs MemPalace (Open-Source, Benchmarked)

Rohit Raj — Sat, 06 Jun 2026 15:14:31 +0000

Agent memory — not the model — is the 2026 bottleneck. MemPalace just hit 54.1k GitHub stars and shipped v3.4.0 with a 96.6% LongMemEval score and zero API calls. Here's how the four open-source AI agent memory layers (Mem0, Zep, Letta, MemPalace) actually compare on architecture, real benchmarks, and honest licensing — plus a code snippet to add memory in minutes and how I'd wire it into a production agent.

Read the full version with code samples, diagrams, and architecture details: AI Agent Memory in 2026: Mem0 vs Zep vs Letta vs MemPalace (Open-Source, Benchmarked)

More engineering notes: rohitraj.tech/en/notes

Claude AI Vulnerability Scanner: Anthropic's Open-Source Code-Security Harness (2026)

Rohit Raj — Fri, 05 Jun 2026 05:21:28 +0000

Anthropic open-sourced defending-code-reference-harness — a Claude-powered pipeline that finds and patches security bugs in your code — and it hit the GitHub Trending front page this week. Here's what actually shipped, how to run /vuln-scan on your own repo, how it compares to the claude-code-security-review Action, managed Claude Security, and Snyk/Semgrep/CodeQL, where it quietly breaks, and how I'd wire it into a production CI without burning your token budget.

Read the full version with code samples, diagrams, and architecture details: Claude AI Vulnerability Scanner: Anthropic's Open-Source Code-Security Harness (2026)

More engineering notes: rohitraj.tech/en/notes