ChatGPT

Perplexity

Perplexity is an AI “answer engine” that responds to questions with concise, cited answers drawn from live web sources, blending search with conversational AI. It is popular for research and quick, sourced answers.

Claude

Claude is Anthropic's family of large language models and conversational assistant, designed with a focus on being helpful, harmless, and honest. It is known for strong long-form reasoning, careful instruction-following, and large context windows that allow it to work with entire codebases or lengthy documents at once. Projects let users organize conversations around persistent context, such as a codebase or a set of reference documents, so Claude can stay consistent across many related tasks. Artifacts create a side-by-side workspace for iterating on code, documents, and diagrams generated during a conversation. Claude is available directly via claude.ai, as an API for developers building on top of the model, and integrated into products like Claude Code for agentic software development tasks.

Google Gemini

Gemini is Google’s family of multimodal AI models and assistant, capable of text, image, and reasoning tasks and integrated across Google products like Search, Workspace, and Android. It competes directly with ChatGPT and Claude.

claude-obsidian

Claude Obsidian is an AI-powered chatbot designed to work seamlessly with Obsidian, a popular note-taking and knowledge management tool. With Claude, users can interact with their Obsidian vault using natural language, making it easier to manage and retrieve information.

gpt4free

gpt4free offers unrestricted access to GPT‑4 through a simple web interface, letting users experiment with advanced language models without any cost. Designed for researchers, students, and developers, it runs entirely in the cloud, eliminating the need for local installations or API keys. The platform provides a responsive chat experience, supports multi‑turn conversations, and includes basic export options for saving results. With email support and open‑source transparency, gpt4free aims to democratize AI research and learning.

Agent-Reach

Agent Reach is a command‑line utility that enables AI agents to fetch content from popular public platforms such as Twitter, Reddit, YouTube, GitHub, Bilibili and XiaoHongShu. It returns the data in a structured format that downstream agents can consume directly. The tool requires no per‑platform credentials, simplifying integration for developers. Documentation is provided in English, Chinese, Japanese and Korean, making it accessible to a global developer audience.