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4 posts tagged “thariq-shihipar”

2026

A Fireside Chat with Cat and Thariq from the Claude Code team

Visit A Fireside Chat with Cat and Thariq from the Claude Code team

Earlier this month I hosted a fireside chat session at the AI Engineer World’s Fair with Cat Wu and Thariq Shihipar from Anthropic’s Claude Code team. We talked about Claude Code, Claude Tag, Fable, coding agent security, evals, tool design, and how Anthropic use these tools themselves.

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One of the most interesting tips I got from the Fireside Chat I hosted with Cat Wu and Thariq Shihipar from the Claude Code team at AIE on Wednesday was to let Fable (and to a certain extent Opus) use their own judgement rather than dictating how they should work.

The example they gave was testing. You can tell Fable "only use automated testing for larger features, don't update and run tests for small copy or design changes" - but it's better to just tell Fable to use its own judgement when deciding to write tests instead.

Jesse Vincent just gave me a related tip to help avoid burning too many of those valuable Fable tokens in the few days we have left before the prices go up. Tell Fable to use other models for smaller tasks, applying its own judgement about which model to use.

I prompted Claude Code just now with:

For all coding tasks use your judgement to decide an appropriate lower power model and run that in a subagent

Claude saved this memory file in ~/.claude/projects/name-of-project/memory/delegate-coding-to-subagents.md:

---
name: delegate-coding-to-subagents
description: Simon wants coding tasks delegated to subagents running an appropriately lower-power model
metadata: 
  node_type: memory
  type: feedback
  originSessionId: 30068d78-43a9-4fb1-bb29-9799e18c526a
---

Stated by Simon on 2026-07-03: "For all coding tasks use your judgement to decide an appropriate lower power model and run that in a subagent."

Why: cost/efficiency — implementation work rarely needs the top-tier model; judgment, review, and synthesis stay with the main loop.

How to apply: when a task in this project is primarily writing/editing code, spawn an Agent with a model override (sonnet for substantive implementation, haiku for trivial/mechanical edits) and a self-contained prompt; review the result in the main loop before committing. Design, auditing, data synthesis, and anything judgment-heavy stays in the main model. See also [[project-goals]].

So far it seems to be working well. I'm getting a ton of work done and my Fable allowance is shrinking less quickly than before.

# 3rd July 2026, 6:51 pm / ai, prompt-engineering, generative-ai, llms, anthropic, claude, coding-agents, claude-code, claude-mythos-fable, thariq-shihipar, cat-wu

Using Claude Code: The Unreasonable Effectiveness of HTML. Thought-provoking piece by Thariq Shihipar (on the Claude Code team at Anthropic) advocating for HTML over Markdown as an output format to request from Claude.

The article is crammed with interesting examples (collected on this site) and prompt suggestions like this one:

Help me review this PR by creating an HTML artifact that describes it. I'm not very familiar with the streaming/backpressure logic so focus on that. Render the actual diff with inline margin annotations, color-code findings by severity and whatever else might be needed to convey the concept well.

I've been defaulting to asking for most things in Markdown since the GPT-4 days, when the 8,192 token limit meant that Markdown's token-efficiency over HTML was extremely worthwhile.

Thariq's piece here has caused me to reconsider that, especially for output. Asking Claude for an explanation in HTML means it can drop in SVG diagrams, interactive widgets, in-page navigation and all sorts of other neat ways of making the information more pleasant to navigate.

I wrote about Useful patterns for building HTML tools last December, but that was focused very much on interactive utilities like the ones on my tools.simonwillison.net site. I'm excited to start experimenting more with rich HTML explanations in response to ad-hoc prompts.

Trying this out on copy.fail

copy.fail describes a recently discovered Linux security exploit, including a proof of concept distributed as obfuscated Python.

I tried having GPT-5.5 create an HTML explanation of the exploit like this:

curl https://copy.fail/exp | llm -m gpt-5.5 -s 'Explain this code in detail. Reformat it, expand out any confusing bits and go deep into what it does and how it works. Output HTML, neatly styled and using capabilities of HTML and CSS and JavaScript to make the explanation rich and interactive and as clear as possible'

Here's the resulting HTML page. It's pretty good, though I should have emphasized explaining the exploit over the Python harness around it.

Screenshot of a dark-themed technical document titled "What this Python script does". Body text: "This is a compact, deliberately obfuscated Linux-specific local privilege-escalation proof-of-concept. Its apparent goal is to tamper with the in-memory image/page cache of /usr/bin/su, then execute su to obtain elevated privileges." A yellow-bordered callout reads: "Safety note: This explanation is for code understanding, reverse engineering, and defensive analysis. Do not run this on systems you do not own or administer. On a vulnerable kernel, code like this can alter the behavior of a privileged executable." Left column heading "High-level summary": "The script opens /usr/bin/su read-only, decompresses an embedded binary payload, and then processes that payload in 4-byte chunks. For each chunk, it performs a carefully arranged sequence involving Linux's kernel crypto socket interface, AF_ALG, pipes, and splice(). The important point is that this is not ordinary file writing. It never calls write() on /usr/bin/su. Instead, it appears to rely on a kernel bug/primitive involving spliced file pages and the crypto API to get controlled bytes placed into the page-cache representation of a privileged executable." Numbered steps follow: "1. Open target executable — /usr/bin/su is opened read-only. 2. Decode hidden payload — A zlib-compressed hex blob is decompressed into bytes. 3. Patch in 4-byte chunks — The helper function is called repeatedly with offsets 0, 4, 8, ...". Right column heading "Why it looks strange" contains a table with Pattern and Purpose columns: "import os as g — Short aliasing to make the script compact and harder to read. socket(38, 5, 0) — Uses raw numeric Linux constants instead of readable names. Compressed hex blob — Hides binary payload bytes and keeps the script small. splice() — Moves file-backed pages through pipes without normal user-space copying. try: recv(...) except: 0 — Triggers the kernel operation and ignores expected errors."

# 8th May 2026, 9 pm / html, security, markdown, ai, prompt-engineering, generative-ai, llms, llm, claude-code, thariq-shihipar

Long running agentic products like Claude Code are made feasible by prompt caching which allows us to reuse computation from previous roundtrips and significantly decrease latency and cost. [...]

At Claude Code, we build our entire harness around prompt caching. A high prompt cache hit rate decreases costs and helps us create more generous rate limits for our subscription plans, so we run alerts on our prompt cache hit rate and declare SEVs if they're too low.

Thariq Shihipar

# 20th February 2026, 7:13 am / ai, prompt-engineering, generative-ai, llms, anthropic, ai-agents, claude-code, thariq-shihipar