Improve all readmes (#188)

* Improve all readmes

* Address some of the comments

mcp-client-rust/README.md

@@ -1,6 +1,35 @@
 # An LLM-Powered Chatbot MCP Client written in Rust
 
-See the [Build an MCP client](https://modelcontextprotocol.io/docs/develop/build-client) tutorial for more information.
+An interactive chatbot MCP client: it launches an MCP server over stdio, lists its tools, and hands them to Claude, which can call them while answering your questions.
+
+This example accompanies the [Build an MCP client](https://modelcontextprotocol.io/docs/develop/build-client) tutorial.
+
+## Prerequisites
+
+- Rust (stable) and Cargo
+- An [Anthropic API key](https://console.anthropic.com/) (optional — see below)
+
+## Setup
+
+Export your API key, or put it in a `.env` file in this directory (the `.env` file is optional):
+
+```bash
+export ANTHROPIC_API_KEY=your-api-key-here
+```
+
+## Run the client
+
+Pass the command that starts the server — a binary or a script — after `--`:
+
+```bash
+cargo run -- ../weather-server-rust/target/release/weather
+```
+
+(Build the server first with `cargo build --release` in its directory.)
+
+Type a question (for example, "What's the weather in Sacramento?") and Claude answers using the server's tools. Type `quit` to exit.
+
+Without an `ANTHROPIC_API_KEY`, the client still connects, prints the server's tools, and exits — useful for verifying the MCP wiring without credentials.
 
 ## Structured content