#488 tau - it's 2pi and it writes code

**Topics covered in this episode:** - **The trusted-publishing debate: how to do it right vs. why you shouldn't trust it** - JupyterLab 4.6 and Notebook 7.6 are out! - **Tau – new small, readable terminal coding agent** - Django Tasks and Django 6.1 - **Extras** - **Joke** Watch on YouTube **About the show** Sponsored by us! Support our work through: - Our courses at Talk Python - Consulting from Six Feet Up **Connect with the hosts** - Michael: Mastodon / BlueSky / X / LinkedIn - Calvin: Mastodon / BlueSky / X / LinkedIn - Show: Mastodon / BlueSky / X Join us on YouTube at pythonbytes.fm/live to be part of the audience. Usually **Tuesday at 7am PT**. Older video versions available there too. Finally, if you want an artisanal, hand-crafted digest of every week of the show notes in email form? Add your name and email to our friends of the show list, we'll never share it. **Calvin #1:** The trusted-publishing debate: how to do it right vs. why you shouldn't trust it https://snarky.ca/how-to-publish-to-pypi-using-github-actions-securely/ (Brett Cannon) and https://blog.yossarian.net/2026/07/07/You-shouldnt-trust-trusted-publishing (W**illiam Woodruff**) - Trusted Publishing (PyPI's OIDC-based auth scheme, also now used by npm, RubyGems, crates.io, NuGet) replaces long-lived API tokens with short-lived, auto-scoped credentials tied to CI/CD machine identity. - Yossarian's post: it's purely an *authentication* mechanism between a machine identity and a package — it says nothing about package safety or quality. PyPI deliberately avoids any "verified/trusted" badge for it, unlike its verified-URL checkmarks. - Same logic applies to PyPI attestations: anyone can sign with any machine identity they control, so an attestation's presence isn't itself a trust signal. - Bottom line from that post: don't confuse "trusted" (machine-to-machine) with "trustworthy" (human judgment about the package). - Snarky.ca's companion piece is more practical: given GitHub Actions compromises in the news, the real fix is 3 concrete steps — run zizmor to lock down workflow permissions/checkout credentials and pin actions to commit hashes, adopt Trusted Publishing to eliminate stored PyPI tokens, and require manual approval via a GitHub environment before any publish job runs. - Takeaway for listeners: Trusted Publishing is good hygiene for *how* you authenticate to PyPI, but it's not a substitute for securing your CI pipeline itself — or for actually vetting the packages you install. **Michael #2: JupyterLab 4.6 and Notebook 7.6 are out!** Michał Krassowski's rundown - a chunky minor release: 68 features, 97 bug fixes, 95 contributors, one of the biggest ever. - **Scratchpad console** (Notebook 7.6 headliner) - a console next to your notebook sharing its kernel, for throwaway experiments. Ctrl+B. - **Jump to last-edited cell** - new commands hop through recently edited cells. - **File browser glow-up** - Date Created column, editable breadcrumbs with Tab-completion, and Open in Terminal. - **Debugger** - sources open in the main area, floating step/continue overlay, live kernel-sources filter. - **Custom layouts (Lab)** - activity bar top/bottom, draggable panels, four-way tab splits, per-panel Ctrl+scroll zoom. - **~5x faster extension builds** - webpack → Rspack, and `jupyter-builder` means no full Lab install needed to build extensions. - **Keyboard/a11y** - add shortcuts from the UI (no JSON), Find & Replace in Edit menu (Ctrl+H). **Calvin #3: Tau** – new small, readable terminal coding agent - **Tau** – new small, readable terminal coding agent (Python 3.12+), built as both a working tool and a teaching project for how coding agents work under the hood - Install via `uv tool install tau-ai`, `pipx`, or `pip`; ships a `tau` CLI - Three-layer architecture: `tau_ai` (provider-neutral model layer) → `tau_agent` (reusable "brain": messages, tools, events, loop) → `tau_coding` (CLI/TUI, file & shell tools, sessions) - Supports OpenAI, Anthropic, OpenAI Codex, OpenRouter, Hugging Face, and custom/local OpenAI-compatible endpoints - Built-in tools (read/write/edit/bash), durable JSONL sessions with resume/branching, project instructions via `AGENTS.md`, and context compaction - Core harness is UI-agnostic — same brain can power the TUI, print mode, or a custom frontend — usable as a standalone library too **Michael #4: Django Tasks and Django 6.1** - **Django 6.0 finally ships first-party background tasks** (`django.tasks`) - out of Jake Howard's DEP 14, accepted May 2024, after two decades of everyone bolting on Celery/RQ/Huey. - **It's an API, not a worker.** Django handles task definition, validation, queuing, and result storage - it does not execute them. You bring the backend. - **The default backend traps people.** `ImmediateBackend` runs tasks inline on the request thread and blocks until done - so out of the box `.enqueue()` backgrounds nothing (a 5-second task means a 5-second response). The other built-in, `DummyBackend`, runs nothing at all. Both are dev/test only. - **Nice API otherwise:** slap `@task` on a function, call `.enqueue()`, get back a `TaskResult` you look up later by id - with async twins like `aenqueue()`. Gotcha: args and return values must survive a JSON round-trip, so a tuple sneakily comes back as a list. - **The community local backend to know: `django-tasks-local`** by Chris Beaven (SmileyChris). A `ThreadPoolExecutor` backend that gives real background threads with zero infrastructure - no Redis, no Celery, no database - plus a `ProcessPoolBackend` for CPU-bound work → github.com/lincolnloop/django-tasks-local - **Its catch:** results live in memory, so pending tasks vanish on restart or deploy. Great for dev and low-traffic production; for persistence, drop to Jake Howard's `django-tasks` (DatabaseBackend + worker command). **Extras** Calvin: - Fixing the dictionary with Python 3.14 — Hugo van Kemenade stumbled on - and got fixed - a markup bug in the OED's own citation of a 1706 use of the pi symbol. Michael: - Bunny DNS is now free **Jokes:** - **What's the object-oriented way to become wealthy?** Inheritance - **To understand what recursion is...** You must first understand what recursion is - **3 SQL statements walk into a NoSQL bar.** Soon, they walk out They couldn't find a table.