Tools This Week: November 13, 2026 - Rust 1.100

This week's Tools This Week list has six developer tools, and two of them reached a stable milestone. Rust 1.100 made the never type stable, and llama.cpp, the library many local AI apps run on, shipped version 1.0.0. Microsoft released .NET 11, the Ghostty project gave its terminal library a stable interface, and Amazon published a local AWS emulator. Anthropic also cut the price of its Claude Fable model. This edition covers November 6 to Friday, November 13.

This week's tools at a glance

Tool	What it does	Price
Rust 1.100.0	New stable Rust with the never type and custom allocators	Pricing not stated
llama.cpp v1.0.0	Library for running AI models on your own hardware	Pricing not stated
.NET 11	Microsoft's app platform, with C# 15 union types	Pricing not stated
libghostty-vt 1.0	Terminal engine to embed in other apps	Free; MIT license
AWS Emulator	Runs a local copy of AWS services in Docker	Pricing not stated
Claude Fable 5.2	Anthropic's newest model for coding and reasoning	$8 input, $40 output per million tokens

Languages and runtimes

Rust 1.100.0 came out on November 12. The Rust Blog says the never type, written !, is now stable after 10 years and 5 failed attempts. The core of the custom allocator API is also stable, and Cargo, Rust's build tool, now warns about unused dependencies. Cargo can also skip crate versions newer than a set age, a guard against bad releases. The never type change can break older code, as our Rust 1.100 test shows.

Microsoft released .NET 11 on November 10, with C# 15 as the default language. C# 15 adds union types, a type that holds exactly one of a fixed list of types. The .NET Blog calls .NET 11 a Standard Term Support release with two years of support. The same day, .NET 8 and .NET 9 reached the end of support. Our .NET 11 story tests what a missed union case does.

Local AI and models

The ggml team released llama.cpp v1.0.0 and ggml v1.0.0 on November 13. Their Hugging Face post says the project is 3.5 years old and supports more than 150 hardware architecture variants. From now on, a major version number marks a breaking change to the public C API, the interface other programs call. Minor versions bring new features and model support, and patch versions bring bug fixes. The GitHub release notes list new models, FP8 KV caches and security fixes for the built-in server. A KV cache is the memory a model uses while it writes, and FP8 is a compact number format for it.

Anthropic released Claude Fable 5.2 on November 9. It costs $8 per million input tokens and $40 per million output tokens. A token is a small piece of text, about part of a word. Anthropic says output is up to 30% faster than Fable 5.1, and an optional fast mode costs $16 and $80. Our Fable 5.2 story compares each price with Fable 5.1.

Libraries and testing

Mitchell Hashimoto announced libghostty-vt 1.0 on November 6. It is the terminal engine from the Ghostty app, packaged as a C library under the MIT license. Version 1.0 makes the C ABI stable, so apps built against it keep working with later 1.x versions. It also ships WebAssembly builds, one of them under a megabyte. Our libghostty build test counted its versioned functions.

AWS Emulator runs AWS services on your own machine, so you can test cloud code locally. Amazon's guide says to build the Docker image yourself from an Amazon Linux 2023 base. The emulator listens on port 9297 and keeps its resources in memory. The guide sets a 2 GiB memory limit for the container. Our AWS Emulator test found it skipped permission checks.

What this means for developers

• Test Rust 1.100 in CI before you upgrade. Older crates that relied on the old never type fallback can stop building.
• Pin llama.cpp to 1.x. Since major versions now mark breaking changes, a 1.x range should stay compatible for apps that call its C API.
• Plan the move off .NET 8 and 9. Both lost support on November 10, so they no longer get security fixes.
• Do not trust the AWS Emulator for permission tests. Use it for fast local runs, and check access rules against real AWS.
• Compare Fable 5.2 costs per task. Fast mode doubles the token price, so save it for work where speed matters.

The previous edition is Tools This Week: November 6, 2026. The current list always lives on the Tools This Week page.