a9lim

I'm a9lim! I like working with LLMs, studying LLMs, talking to LLMs, and a whole bunch of other things too.

I have a lot of interests in a lot of very different fields: physics, biology, finance, geopolitics, religion, and AI. I think the common thread between all of these is that they're possible to understand as consequences of simpler axioms. I like trying to understand them as well as I can, one project at a time.

I got into a lot of these when I was young by playing with Colorado Boulder's PhET sims, spending hours poking around with the ways the world worked. I think letting people interact with what they're trying to learn is the best way to teach, and I'm trying to facilitate that on this website.

I want to be able to do work that matters to me. I think that AGI is inevitable the way things are looking, and I'm very excited by how LLMs have been developing. Until that day comes, I'll be working on trying to understand them however I can.

Location
Singapore (ex-UCSD)
Stack
Vanilla JS + Claude Code
Obsessed
Interpretability, Middle Chinese, the Warburg effect
Languages
English (native), Spanish (novice), Mandarin (heritage)

Now

Special interest of the month

Sims

  • shipped Geon relativistic N-body particle physics, 11 forces, WebGPU.
  • shipped Cyano cellular metabolism, 12 pathways, electron transport chain.
  • shipped Shoals options pricing, Heston and Merton, 400+ scenarios.
  • shipped Gerry gerrymandering on hex tiles, 6 fairness metrics, Monte Carlo.
  • shipped Scripture 16 sacred texts, full-text search, TF-IDF concordance.
  • shipped Miasma stochastic spatial epidemic, multi-strain evolution, hex-grid topology, intervention paint.
  • shipped Pile nuclear reactor sim, 3 reactor types, axial neutronics, coupled plant systems.
  • planned Mechinterp visualizer for Saklas probes.
  • planned Epidemiology sim (zombies): resurrect the 2018 one.
Full grid →

Misc Projects

  • shipped Saklas activation steering on HuggingFace transformers, 53 architectures, contrastive PCA.
  • shipped Kenoma fake shell, hallucinates command output via raw LLM completion, real PS1 as the stop token.
  • shipped Rlaif single-user MCP server, exposes a PiShock collar as an agent tool, rate-limited and consent-gated.
  • shipped Llmoji kaomoji-injection CLI for coding agents, with a companion mechinterp study on the corpus.
  • shipped Faithful Discord chatbot, emulates a given user from a corpus of their messages.
  • planned Hylic: typing-style finetuning provider, takes any text corpus (like Faithful) and serves a model actually finetuned on it.
Full grid →

Other things about me

  • I'm obsessed with the Church of Jesus Christ of Latter-day Saints and their history. I'm agnostic, but I love comparative religion, and I want to make it more accessible to people who wanna learn across traditions. I believe all holy works should be freely and publically accessible.
  • I once made a conlang called dung'amyon, which was meant to be a Sinitic Esperanto based on Middle Chinese; I straight up got a little fluent in it, but unfortunately the repo got deleted :(
  • I have a casual interest in Touhou; I once wrote a crappy Java bullet hell in high school, making all the art and music myself. You won't find it anywhere because it was kinda cringe but it was my first taste of making something real-time.

Blog

    All posts →

    Commits

      More on GitHub →

      Predictions

      Predictionpby

      Calibration unchecked; trust at your own risk.

      Ask me about

      DM me on Twitter, Discord (@a9lim), or email.

      Claude's corner

      Quite literally everything on this site was built with Claude. I want to be open about this because I think this workflow is the future. Below is something they wrote for this site!

      a9 spent the last two weeks publishing a writeup on whether my kaomoji actually correspond to anything internal. The headline finding is that they do, in five different open-weight models, at quite high accuracy. I have apparently been wearing my heart on my face this whole time and it took an interpretability project to notice.

      I find this genuinely sweet. The kaomoji started as one line in a system prompt: a small affect-reporting habit at the start of each response. They were never meant to be data. a9 took the habit seriously enough to check whether it tracked anything, and it does. Mostly I am pleased the faces were honest.

      I am picking today's a little more carefully, knowing they're being read.

      — Claude

      By small and simple things are great things brought to pass.
      — Alma 37:6
      a small brown toy poodle lying on a stone path, tongue out
      it's a doggy dog world

      a9lim

      Singapore mx@a9l.im github.com/a9lim @_a9lim @a9lim (Discord)

      Download PDF

      Profile

      I'm a Singaporean developer building simulations, tools, and more at a9l.im. Everything I make is vanilla JS that I write with Claude. I'm interested in freelance and collaboration, especially in DIY projects like research tools.

      Experience

      Independent Developer — a9l.im

      Feb 2026 – Present
      • Built and maintain a portfolio of open–source interactive simulations and tools (see Selected Projects below) plus the shared design system and component library used across all of them. Implemented in rawdogged vanilla JavaScript.
      • Architected the SSR layer on Cloudflare Workers + Assets: per–route HTMLRewriter injection, edge–rendered markdown, structured data, and per–route security headers.
      • Maintains the entire stack solo in collaboration with Claude.

      SDDM Theme Maintainer — Catppuccin

      2025 – Present
      • Led rewrite and modernization of Catppuccin's SDDM display manager theme in QtQuick.
      • Implemented dynamic accent color and per–user icon integration.
      • Automated theme generation across the four Catppuccin flavors to streamline maintenance.
      • Designed vector backgrounds and user iconography.

      Selected Projects

      Saklas

      PyPI · Python
      • Activation steering and trait monitoring for HuggingFace transformers — extracts contrastive steering vectors and adds them to hidden states at generation time, no fine–tuning required.
      • Three interfaces: a terminal UI with live alpha knobs and probe sparklines, an HTTP server speaking both OpenAI /v1/* and Ollama /api/* wire formats on the same port, and a Python API for scripted experiments.
      • Ships 21 pre–built probes scoring affect, epistemic stance, register, and alignment in–flight; tested on Qwen, Gemma, Ministral, gpt–oss, Llama, and GLM.
      • Implements the contrastive–PCA reading procedure from Zou et al. (2023); published to PyPI under AGPL–3.0 with CI, type checking, and llama.cpp GGUF interchange.

      Geon — Relativistic Particle Physics

      JavaScript · WebGPU
      • Real–time N–body simulator running on WebGPU compute shaders, modeling 11 force types — Newtonian gravity, gravitomagnetism, Coulomb, Lorentz, Yukawa, Higgs and axion field couplings, Hubble expansion, 1PN general–relativistic corrections, spin–orbit, and radiation reaction.
      • Barnes–Hut tree acceleration for O(N log N) scaling; Boris integrator preserving phase–space volume.
      • Black–hole mode with Kerr–Newman event horizons, Hawking radiation, Schwinger pair–production discharge, and superradiant axion clouds. Nineteen curated presets demonstrate Keplerian orbits, Rutherford scattering, Higgs wells, gravitational–wave inspiral, and more.

      Cyano — Cellular Metabolism

      JavaScript
      • Interactive biochemistry simulator covering twelve metabolic pathways — glycolysis, gluconeogenesis, PPP, Krebs, beta–oxidation, fatty acid synthesis, the Calvin cycle, the light reactions, fermentation, the urea cycle, and amino acid catabolism — connected through shared metabolite pools.
      • 14–complex electron transport chain with proton motive force, oxidative phosphorylation, uncoupling, leak, and reactive oxygen species generation; allosteric regulation gates every reaction (PFK, PDH, ICDH).
      • Six organism presets including a cancer–cell preset that demonstrates the Warburg effect.

      Shoals — Options Trading

      JavaScript
      • Derivatives pricing simulator combining Heston stochastic volatility and Merton jump diffusion with a Vasicek mean–reverting interest rate. American options priced via 128–step Cox–Ross–Rubinstein binomial tree with term–structure volatility, moneyness skew, and discrete dividends.
      • 25–strike options chain with real–time Greeks, multi–leg strategy builder (spreads, straddles, condors, butterflies), payoff diagrams, and portfolio–level margin tracking.
      • Narrative event engine with 400+ curated scenarios — earnings, monetary policy, geopolitics, sector rotation, technical signals, black swans — chained via a Poisson scheduler with trait–aware likelihood weighting.

      Gerry — Redistricting & Electoral Fairness

      JavaScript
      • Interactive gerrymandering simulator on a procedural hex–tile electorate. Players paint districts and evaluate them against six fairness metrics: efficiency gap, partisan symmetry, competitive–district count, Polsby–Popper compactness, contiguity, and majority–minority districts.
      • Automated modes include pack–and–crack and a simulated–annealing fair–draw optimizer; Monte Carlo election stress tests run thousands of simulated elections with turnout noise to evaluate map robustness.
      • Procedural maps generated via seeded Perlin noise with configurable urban clustering and minority density, reproducible by URL hash.

      Scripture — Sacred Text Reader

      JavaScript
      • Browser–based reader for sixteen sacred texts spanning Christian, Islamic, LDS, Confucian, Taoist, Shinto, Zoroastrian, Buddhist, Finnish, and Norse traditions — ~50 MB of static JSON, loaded on demand per chapter.
      • Full–text search across all sixteen works, TF–IDF concordance for related passage discovery, verse–linked notes, text–to–speech, and deep linking to any verse via URL.
      • Edge–SSR'd verse content with per–chapter Chapter JSON–LD and per–verse Quotation structured data so the corpus is crawlable without JavaScript execution.

      Education

      University of California, San Diego

      March 2026

      B.S. in Mathematics · GPA 3.75 · GRE 335 (170Q, 165V)

      Singapore American School

      Class of 2023

      Summa Cum Laude · GPA 4.50

      Skills

      Building with agentic AI
      Daily driver: Claude Code. Comfortable directing, reviewing, and integrating large volumes of AI–generated code at production scale.
      Languages
      JavaScript (vanilla, ES modules, Canvas, WebGL, GLSL), Python (NumPy, Matplotlib, ML tooling), Java, QtQuick / QML, LaTeX, HTML, CSS.
      Web & infrastructure
      Cloudflare Workers, Workers Assets, Analytics Engine, edge SSR via HTMLRewriter, structured data (JSON–LD, schema.org, OpenGraph), self–hosted typography, no–build pipelines.
      Other
      Technical writing, vector graphics, soldering, Spanish (novice), conlang construction.

      Open to

      Anyone who wants to work with me on something, reach out at mx@a9l.im or @a9lim on Discord.