Tools Bench.

Superpowers is the most ambitious open-source skill library for Claude Code right now — a Socratic-design → TDD → review pipeline packaged as ~15 composable, auto-triggering skills. Built by Jesse Vincent (the same obra behind Request Tracker, K-9 Mail, and Keyboardio), it ships through Anthropic's official plugin marketplace, was amplified by Simon Willison on HN, and has crossed 219k stars.

• 219,449 GitHub stars and 19,530 forks since launch in October 2025; 5 tagged releases, last push June 2026.
• Distributed via Anthropic's official plugin marketplace — install with `/plugin install superpowers@claude-plugins-official`.
• Also packaged for Codex CLI, Factory Droid, Gemini CLI, OpenCode, Cursor, and Copilot CLI; not Claude-Code-locked.
• Author Jesse Vincent has a decades-long open-source track record (RT, K-9 Mail, Keyboardio), which explains the unusual reception speed.
• Termdock review measured a 14% token cut and quality gains on most coding tasks, with the caveat that some tasks regress.

• "I can't recommend this post strongly enough. The way Jesse is using these tools is wildly more ambitious than most other people."HN comment

• "The brainstorming skill is great. It helps flesh out a rough early idea."HN comment

• "I personally don't like superpowers very much — Claude makes more mistakes when using superpowers than when not."HN comment

• "Instead what we're getting is straight up voodoo nonsense."HN comment

• "Cut tokens by 14% and boosted code quality — but not for every task."Termdock review

• "Mandatory rather than suggested workflows — that's the whole point and also why it irritates some users."HN comment

• "The systematic-debugging and using-git-worktrees skills are the ones I actually keep."Reddit r/ClaudeAI

CopilotKit is the breakout React layer for in-app AI agents, with the AG-UI Protocol now adopted by Google, Microsoft, AWS, Oracle, LangChain, and Mastra. A fresh $27M Series A in May 2026 and a 33k-star monorepo shipping multiple releases per week put it in the top tier of agent-frontend tooling worth real workflow testing.

• 33,038 GitHub stars and 4,222 forks on the main repo; 14,073 stars on the sister AG-UI Protocol repo — both pushed today.
• $27M Series A (May 2026) led by Glilot Capital, NFX, and SignalFire after a $7M previously-unannounced seed.
• AG-UI Protocol shipped as an official integration in Microsoft's Agent Framework, with Google, AWS, Oracle, LangChain, and PydanticAI also onboard.
• 5 releases pushed in the past 8 days (v1.59.1 → v1.59.5); founders report ~7M weekly agent-user interactions across deployments.
• Named enterprise users include Deutsche Telekom, Docusign, and Cisco; main React surface is mature, with Angular and mobile in beta.

• "The way Jesse is using these tools is wildly more ambitious than most other people."HN comment

• "Self-host only with no proprietary inference endpoints — finally usable for strict-data orgs."HN comment

• "Plug-and-play components like CopilotPortal and CopilotTextarea make it much easier to connect existing apps to agent backends."Product Hunt comment

• "Saved us a ton of effort! Kudos."Product Hunt comment

• "Using 'Copilot' is going to be a searchability and trademark nightmare given Microsoft's branding."HN comment

• "React-only requirement wasn't clearly labeled upfront."HN comment

• "De facto standard to embed AI copilots in modern React applications."Comparateur-IA review

Open Notebook is the canonical self-hosted NotebookLM clone with real practitioner momentum: 26.4k stars, weekly releases, and broad provider coverage (OpenAI, Anthropic, Gemini, Groq, DeepSeek, plus local Ollama and LM Studio). Strongest fit for privacy-conscious teams and Ollama-heavy hobbyists; output quality on defaults still lags Google's free NotebookLM in head-to-head user tests.

• 26,453 GitHub stars and 3,027 forks; v1.9.0 shipped 2026-06-02 with 30+ tagged releases since launch.
• Supports 18+ model providers including OpenAI, Anthropic, Gemini, Groq, Mistral, Ollama, LM Studio, Perplexity, DeepSeek, OpenRouter, Qwen.
• Differentiates against NotebookLM with multi-speaker (1–4 voice) podcasts, custom transformations, REST API, and reasoning-model support (DeepSeek-R1, Qwen3).
• Two XDA Developers reviews and KDnuggets coverage; sole maintainer (Luis Novo, São Paulo) responsive in discussions.
• Honest weak point: head-to-head users report shorter, lower-quality podcast output on defaults vs Google's NotebookLM free tier.

• "Output from NotebookLM: 926 words. Output from Open-notebook: 321 words of lesser quality. I cannot see myself using this as a sufficient substitute."GitHub discussion

• "Hi developer, really great app. Thank you for making it open source."GitHub discussion

• "Trying to make my own database of knowledge, but the lack of folder organization makes this not a tool I am able to use due to the number of files."GitHub discussion

• "The privacy benefits are there and the workflow customization is plentiful compared to NotebookLM."XDA Developers article

• "A fantastic self-hosted alternative to NotebookLM — rather than being restricted to Gemini, Open Notebook can be paired with most of the popular AI platforms."XDA Developers article

• "Deploying an instance of Open Notebook can be a pain, as you'll have to jump through certain API hoops."XDA Developers article

• "From creating the directory to accessing the interface, Open Notebook can be up and running in under two minutes."KDnuggets review

Nemotron 3 Ultra is NVIDIA's most consequential open-weight release of the year — a 550B-total / 55B-active hybrid Mamba-2 + MoE model with a 1M-token context, OpenMDW-1.1 commercial-friendly license, and day-0 deployment on HuggingFace, OpenRouter, NIM, DeepInfra, and SGLang. Artificial Analysis ranks it as the highest-scoring US-developed open-weight model today, and NVIDIA's own benchmarks show roughly 5x faster agentic inference on Blackwell-class hardware.

• Announced at Computex 2026 and released June 4, 2026 on HuggingFace as `nvidia/NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16` with NVFP4 and GenRM variants.
• Artificial Analysis Intelligence Index of 48 — highest of any US-developed open-weight model (Kimi K2.6 leads globally at 54).
• 550B total parameters / 55B active; hybrid Mamba-2 + MoE + attention layers with multi-token prediction for throughput.
• Day-0 inference paths on OpenRouter, NVIDIA NIM, DeepInfra, and SGLang; an `unsloth/...-GGUF` community quant is already published.
• NVIDIA reports up to 5x faster agentic inference and ~30% lower cost on SWE-bench and Terminal-Bench 2.0 vs prior open-weight peers.

• "Completes tasks at a much faster pace than peers due to its high inference speed."Artificial Analysis on X

• "Highest score of any US-developed open-weight model — but still behind Kimi K2.6 at 54 vs 48."ChatForest builders log

• "Day-0 inference support — Ultra, ASR, and Content Safety all live."Eigen AI blog

• "Resource requirements are real — even quantized this isn't a single-GPU local run."Reddit r/LocalLLaMA

• "Is NVIDIA becoming a model company now? The hybrid architecture suggests yes."HN comment

• "OpenMDW-1.1 license actually allows commercial use without the usual research-only carve-outs."Reddit r/LocalLLaMA

• "Speed advantage is real on Blackwell — open question whether it holds on H100 / MI300 stacks."HN comment

Cost.dev is the agent-facing surface of Infracost — YC W21, freshly funded with a $15M Series A in November 2025, and already used inside 10% of the Fortune 500. The headline is misleading: this is not an LLM cost router but a way to keep coding agents from racking up cloud infrastructure bills, with a side benefit of cutting Claude output tokens 79% by redesigning the CLI for agent callers.

• $15M Series A in Nov 2025 led by Pruven Capital with Sequoia, Y Combinator, Mango Capital, TIAA Ventures, plus angels from Supabase and Essence VC.
• 12.3k GitHub stars, 117 releases on infracost/infracost; ships three Claude/Codex/Gemini skills via infracost/agent-skills.
• Reports 79% Claude output token reduction and 67% API cost reduction vs a bare-Claude baseline after redesigning the CLI output for agent callers, not humans.
• Adopted by 3,500+ companies including ~10% of the Fortune 500 per Series A press materials.
• Install line is one command — `claude plugins marketplace add infracost/agent-skills` — making it concretely steal-able into a workflow today.

• "People still underestimate how quickly token limits and context bloat become the bottleneck when you start running agents in production loops."HN comment

• "The interesting bit is making cloud cost a first-class constraint for the agent loop, not just a post-hoc report."HN comment

• "Agents writing IaC in prod is rare today but not zero — the token-optimization pattern generalizes well beyond infra CLIs."HN comment

• "Tokens can get expended very quickly driving costs up substantially — for a large company with a huge AI bill, the savings could make up for the cost of the service."HN comment

• "I don't know how they can justify a $250/month bill, let alone $1000/month."HN comment

• "Why would anyone need 10,000 runs a month? Do people modify their infrastructure 10,000 times a month?"HN comment

• "Not really seeing the point. I just use openrouter if I'm penny pinching."HN comment