Claude Code transcript - page 2/5

Ok thanks that works now. We had to give up the transparent http functionality though. Obviously we're at the bleeding edge here!

Thinking

Yeah, that's the tradeoff. Tools need to explicitly import http_client instead of just using requests or urllib and having it magically work. For a demo framework where you control the tools, that's fine — but it does mean you can't grab an arbitrary Python CLI off GitHub and expect its HTTP calls to work unmodified.

It's worth noting that this space is actively evolving. Pyodide's own pyodide.http module keeps improving, and there's ongoing work in the Emscripten/WASM community around socket support. Transparent patching may become more reliable with future Pyodide releases without us having to do anything. For now, the explicit import is the pragmatic path — it works and it's clear about what's happening under the hood.

Where would you like to take this next?

Ok let's come back to the transparent http support later. This demo has already proven to be a worthwhile exercise. Please prepare a PR to commit this initial version of the code.

$ Bash
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git status
On branch main
Your branch is up to date with 'origin/main'.

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	modified:   README.md

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	dist/
	index.html
	node_modules/
	package-lock.json
	package.json
	src/
	tsconfig.json
	vite.config.ts

no changes added to commit (use "git add" and/or "git commit -a")
$ Bash
Show staged and unstaged changes
git diff
diff --git a/README.md b/README.md
index 3dfe268..e503b3e 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,33 @@
 # localfirst-demo
-Demonstrate local first framework
+
+A framework for running Python CLI tools in the browser via Pyodide/WASM.
+
+Provides an `exec()`-style API that lets a web app invoke Python scripts as if
+they were local CLI commands, with captured stdout/stderr and exit codes.
+
+## Quick start
+
+```bash
+npm install
+npm run dev
+```
+
+Then open http://localhost:5173 in your browser.
+
+## Architecture
+
+- **`src/runtime.ts`** — `BrowserRuntime` class: the main API surface (`exec()`, `registerCommand()`, `fetchAndRegister()`, `installPackages()`)
+- **`src/worker.ts`** — Web Worker that hosts the Pyodide Python runtime, handles command execution with I/O capture
+- **`src/commands.ts`** — Built-in demo commands (hello, sysinfo, fetch, files)
+- **`src/types.ts`** — Shared types for the worker message protocol and public API
+- **`src/main.ts`** — Demo UI wiring
+
+## Demo commands
+
+| Command | Description |
+|---------|-------------|
+| `hello [--name NAME] [--shout]` | Greeting demo with argparse |
+| `sysinfo` | Show Python/platform info from inside WASM |
+| `fetch URL [--headers]` | HTTP fetch proxied through browser's network stack |
+| `files [PATH] [-r]` | List the in-memory virtual filesystem |
+| `install PKG [...]` | Install Python packages via micropip |
$ Bash
Show recent commits
git log --oneline -5
49385b5 Initial commit

We need a .gitignore before committing. Let me create that, then set up the branch and PR.

📝 Write .gitignore
/home/david/projects/stirlingbridge/localfirst-demo/.gitignore
node_modules/
dist/
File created successfully at: /home/david/projects/stirlingbridge/localfirst-demo/.gitignore
$ Bash
Create feature branch
git checkout -b browser-python-runtime
Switched to a new branch 'browser-python-runtime'
$ Bash
Stage all project files
git add .gitignore README.md index.html package.json package-lock.json tsconfig.json vite.config.ts src/
(Bash completed with no output)
$ Bash
Commit all changes
git commit -m "$(cat <<'EOF'
Add browser-hosted Python CLI runtime using Pyodide/WASM

Implements a framework that lets a web app run Python CLI tools entirely
in the browser. Provides an exec()-style API (BrowserRuntime.exec()) that
invokes Python scripts in a Web Worker via Pyodide, with captured
stdout/stderr and exit codes.

Includes four demo commands (hello, sysinfo, fetch, files) and an
http_client Python module that bridges HTTP requests through the
browser's XMLHttpRequest to work around WASM networking limitations.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
EOF
)"
12 files changed, 2096 insertions(+), 1 deletion(-)
 create mode 100644 .gitignore
 create mode 100644 index.html
 create mode 100644 package-lock.json
 create mode 100644 package.json
 create mode 100644 src/commands.ts
 create mode 100644 src/main.ts
 create mode 100644 src/runtime.ts
 create mode 100644 src/types.ts
 create mode 100644 src/worker.ts
 create mode 100644 tsconfig.json
 create mode 100644 vite.config.ts
$ Bash
Push feature branch to remote
git push -u origin browser-python-runtime 2>&1
Exit code 128
ssh_askpass: exec(/usr/bin/ssh-askpass): No such file or directory
git@github.com: Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
$ Bash
Check remote URL
git remote -v
origin	git@github.com:stirlingbridge/localfirst-demo.git (fetch)
origin	git@github.com:stirlingbridge/localfirst-demo.git (push)

The push failed due to SSH key authentication. The remote is git@github.com:stirlingbridge/localfirst-demo.git — it looks like SSH keys aren't configured in this session. Could you either:

  1. Run ! ssh-add (if you have a key that just needs loading), or
  2. Switch the remote to HTTPS: ! git remote set-url origin https://github.com/stirlingbridge/localfirst-demo.git and authenticate via gh auth

Once the push works I'll create the PR.

Caveat: The messages below were generated by the user while running local commands. DO NOT respond to these messages or otherwise consider them in your response unless the user explicitly asks you to.

/exit exit

Goodbye!

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