Notes

TIL: You can set IS_DEMO=1 to simplify the welcome screen of Claude Code. There are two types of welcome screens (shown below), and there’s no obvious logic behind which one appears for a given project — I found this annoying. After digging into it, I discovered an undocumented environment variable IS_DEMO¹ that forces the simpler one. Run IS_DEMO=1 claude, or set it in Claude Code’s settings.json under the env key.

TIL: $TMPDIR is an environment variable set by macOS (not fish-specific) that points to a per-user temporary directory. Its value looks something like:

/var/folders/xx/xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/T/

The path is unique per user and per boot session — macOS generates it under /var/folders/. Files here are:

• Automatically cleaned up by the system. macOS periodically purges files in /var/folders/ that haven’t been accessed recently (typically after 3 days of inactivity, managed by the periodic daily scripts). A reboot also clears them.
• Not shared across users, since each user gets their own subdirectory.

On Linux, $TMPDIR is often unset; the conventional fallback is /tmp.

Don’t Let AI Write For You¹. Nicely distilled essay on writing.

I just renamed my two journal websites. Over the weekend, I spent some time thinking carefully about the positioning and goals of the two sites, and eventually made this decision. The English technical site is now Hack at https://hack.zlliang.me, and the Chinese personal site is now Muse at https://muse.zlliang.me.

This change updates the public branding, site names, workspace paths, and shared references from the earlier tech and days naming. I also updated the Vercel domains, and the old tech and days domains now redirect to the new ones. The commit is zlliang/zlliang@cf59692.

After the rename, I feel more confident that the two sites can grow for longer and on steadier footing.

I just finished a full Git history cleanup for my website monorepo to remove oversized historical image blobs. I used to track full-size images in the repo, which is not sustainable as my blogs grow.

I used sharp with a consistent baseline (size, edge limit, and quality ladder) to optimize images before rewriting history. The result was substantial: the total repo size, including history blobs in .git, dropped from about 500+ MB to 70+ MB (about -86%).

This was a Git history rewrite with git-filter-repo, so all commit hashes changed. I also updated commit references in my existing notes, including links in the zlliang/zlliang@xxxxxxx format and corresponding GitHub commit URLs.

After the migration, I also added a pre-commit hook that automatically optimizes newly added images to the same baseline, so future image growth stays controlled during normal commits. That setup was shipped in zlliang/zlliang@c139c11. At runtime, I still rely on Vercel’s image optimization to serve appropriate image variants for different devices and viewport sizes.

Most of the migration scripting, validation, and cleanup in this round was completed with help from Amp.

Markdown Ate The World¹. Recommended reading. Always bet on plain text!

I just added support for post series on both https://tech.zlliang.me and https://days.zlliang.me. There is now a /posts/series index page, each series has its own page, and individual post pages can show the other posts in the same series in the sidebar.

This felt worth adding because some posts are clearly part of a longer thread rather than standalone pieces. On the tech site, Starting a Blog at the End of 2025 and Splitting My Websites and Finalizing My Writing Framework are now grouped under How I Write. On the days site, my January and February monthly posts are now grouped under the Life Monthly series.

The commit is zlliang/zlliang@e858356, which also closed issue #79. Unlike several recent blog infrastructure changes, this one was surprisingly mostly handwritten. I only used a coding agent for a few small parts.

Some Things Just Take Time¹. Recommended reading. About the value of slowing down in this fast-changing world.

Updating the design of Notion pages. Notion is refining the spacing rules across its pages, and that feels like the right direction. I use Notion for private writing and personal databases, so this kind of change could noticeably improve the writing experience for me. I have also spent a long time thinking about spacing while designing my own personal website, so I like that this article treats spacing as a serious design problem. It is a good deep-dive reference.

I just finished a fairly big notes-navigation refresh for both https://tech.zlliang.me and https://days.zlliang.me. Archive pages by year, month, and day are now fully in place, and the sidebar now has a “Writing journey” heatmap.

This makes the notes feel much easier to browse as a body of work instead of a flat reverse-chronological list. For example, visit /notes/2026 for notes in 2026, /notes/2026/03 for notes in March 2026, and /notes/2026/03/19 for notes on Mar 19, 2026. Each cell in the heatmap takes you to the archive page for that specific day.

The work happened in two commits: zlliang/zlliang@9ed325f and zlliang/zlliang@9786f32. Most of the implementation was done with help from the Codex app and Amp.

Introducing GPT-5.4 mini and nano¹. OpenAI finally refreshed its smaller and cheaper models. The previous mini/nano release was GPT-5 in August 2025, while GPT-5.1-Codex-Mini in November 2025 was a more coding-specific branch.

It feels like OpenAI is gradually tidying up its model lineup. At least in the GPT-5.4 family, there is no separate “Codex”-suffixed specialized model, and the mini and nano variants seem to be catching up too.

I checked the Codex app this morning and saw that its built-in subagents are already using GPT-5.4 Mini.

Subagents using GPT-5.4 Mini

Use subagents and custom agents in Codex¹. Subagents are now generally available in Codex, after previously being introduced as an experimental feature called “multi-agents”.

In short, you can ask Codex to spawn subagents that run in parallel with one another and with the main agent. They use their own context windows and report back to the main agent when they are done. Subagents can have their own models and instructions. There are built-in agents like explorer, and you can define your own ones with TOML configuration files under .codex/agents.

One fun detail is that Codex picks a random nickname for each subagent. My first try gave me an explorer subagent called “Galileo”.

Galileo explored the repo for my websites

I first learned about subagents through Amp, which ships several curated custom agents like Oracle and Librarian. What I like about Amp’s approach is that it presents subagents as recommended workflows, not just as a feature to try on your own. By pairing carefully designed agents with specific models and tools, it also shows how subagents fit into everyday work. That has been a consistent strength of Amp: it tends to package what it sees as the current best practice, and that is also where I first started to understand the idea of subagents.

Here are other comments on this Codex release:

• Simon Willison’s post
• Vaibhav (VB) Srivastav’s article: You Should Be Using Subagents in Codex!

Now that major coding agents like Claude Code, OpenCode, and Cursor all support subagents in broadly similar ways, will subagents become a standard, like skills?

VoidZero, the JavaScript tooling company founded by Evan You, the creator of Vue and Vite, released several notable updates over the past week:

• Vite 8, now powered by Rolldown after several years of work (btw, Astro uses Vite under the hood)
• Vite+ alpha, now open-sourced under the MIT license after an earlier plan to make it a paid product, as mentioned in its initial announcement
• Void, a full-stack framework and deployment platform built on top of Cloudflare’s infrastructure

I’ve liked Vue and Vite since the beginning of my career, so these releases are especially interesting to me. I have already applied for early access to Void. More immediately, I am curious about Vite Plus shipping a global Node.js version manager, vp env, and I want to see whether it could replace nodenv in my setup.

I added support for pinned posts on both https://tech.zlliang.me and https://days.zlliang.me in zlliang/zlliang@c283182, which also closed issue #77. There still are no real pinned posts on either site yet. I added the feature in advance for a post draft I am currently writing.

Over the past few days, I have been doing a series of minor blogging overhauls: reworking tags, adjusting parts of the UI, and cleaning up the agent skills and authoring references that support my blogging workflow. The more I work on both sites, the more I want to extract their highly similar logic into an Astro theme, something like my own small blog system in the spirit of Starlight.

One thing has become increasingly clear as I look back over my recent notes: I am doing noticeably better on the Chinese days site than on the English tech site. Part of that is simple fluency. But a more important part is that my technical notes still do not contain enough of my own thinking. Too often, they are just a pile of things I saw, rather than writing that helps me think or build a narrative of my own.

I want to keep that in mind and keep improving through writing.