The Hallway Track

prompt-engineering

10 tracked signals on prompt-engineering.

Discovering cryptographic weaknesses with Claude

Simon Willison · Jul 28, 2026

Claude Mythos found cryptographic weaknesses in HAWK and reduced-round AES after 60 hours and ~$100K in API costs

“no we don't want to change the targets [...] agian we need to find something that worth publishing”
Skills are just fancy prompts. Here's why that matters.

LangChain · Oct 05, 2026

Agent 'skills' are dynamically loaded prompts enabling progressive capability disclosure

“Skills are just prompts, they're fancy prompts, but they're really easy to share and they can help agents really narrow in and do a certain task well.”
Stop Writing Prompts. Start Writing Specs.

Microsoft Developer (Build) · Aug 24, 2026

Enterprises should replace prompt-first AI coding with specification-driven development practices.

“Stop treating the prompt as the main artifact and start treating the specification as that main artifact.”
Designing effective Genie Agents from a single prompt

Databricks Blog · Aug 19, 2026

Databricks Genie Agents require careful single-prompt design to avoid generic data retrieval errors

“Ask a generic agent about revenue, and it'll likely grab the first revenue table”
Quoting David Crawshaw's prompt

Simon Willison · Aug 03, 2026

A nightly cron prompt can automate dependency rebasing and validation via coding agents

“Set up a nightly cron job that executes the prompt: fetch upstream changes to the <software> and rebase all local changes on top of upstream. Check that the software works as intended and replace the current version.”
Build a Portfolio Website from Your Resume with GitHub Copilot

Microsoft Developer (Build) · Aug 21, 2026

GitHub Copilot desktop app can generate a portfolio website directly from a resume PDF.

“my favorite part of writing the prompt is always to create a clear goal as you said. But on top of that, I love to collaborate with the models.”