Simon Willison’s Weblog

llm-mistral 0.14. I added tool-support to my plugin for accessing the Mistral API from LLM today, plus support for Mistral's new Codestral Embed embedding model.

An interesting challenge here is that I'm not using an official client library for llm-mistral - I rolled my own client on top of their streaming HTTP API using Florimond Manca's httpx-sse library. It's a very pleasant way to interact with streaming APIs - here's my code that does most of the work.

The problem I faced is that Mistral's API documentation for function calling has examples in Python and TypeScript but doesn't include curl or direct documentation of their HTTP endpoints!

I needed documentation at the HTTP level. Could I maybe extract that directly from Mistral's official Python library?

It turns out I could. I started by cloning the repo:

git clone https://github.com/mistralai/client-python
cd client-python/src/mistralai
files-to-prompt . | ttok

My ttok tool gave me a token count of 212,410 (counted using OpenAI's tokenizer, but that's normally a close enough estimate) - Mistral's models tap out at 128,000 so I switched to Gemini 2.5 Flash which can easily handle that many.

I ran this:

files-to-prompt -c . > /tmp/mistral.txt

llm -f /tmp/mistral.txt \
  -m gemini-2.5-flash-preview-05-20 \
  -s 'Generate comprehensive HTTP API documentation showing
how function calling works, include example curl commands for each step'

The results were pretty spectacular! Gemini 2.5 Flash produced a detailed description of the exact set of HTTP APIs I needed to interact with, and the JSON formats I should pass to them.

There are a bunch of steps needed to get tools working in a new model, as described in the LLM plugin authors documentation. I started working through them by hand... and then got lazy and decided to see if I could get a model to do the work for me.

This time I tried the new Claude Opus 4. I fed it three files: my existing, incomplete llm_mistral.py, a full copy of llm_gemini.py with its working tools implementation and a copy of the API docs Gemini had written for me earlier. I prompted:

I need to update this Mistral code to add tool support. I've included examples of that code for Gemini, and a detailed README explaining the Mistral format.

Claude churned away and wrote me code that was most of what I needed. I tested it in a bunch of different scenarios, pasted problems back into Claude to see what would happen, and eventually took over and finished the rest of the code myself. Here's the full transcript.

I'm a little sad I didn't use Mistral to write the code to support Mistral, but I'm pleased to add yet another model family to the list that's supported for tool usage in LLM.

# 29th May 2025, 3:33 am / plugins, projects, python, ai, httpx, generative-ai, llms, ai-assisted-programming, llm, claude, mistral, gemini, llm-tool-use, claude-4

files-to-prompt 0.5. My files-to-prompt tool (originally built using Claude 3 Opus back in April) had been accumulating a bunch of issues and PRs - I finally got around to spending some time with it and pushed a fresh release:

• New -n/--line-numbers flag for including line numbers in the output. Thanks, Dan Clayton. #38
• Fix for utf-8 handling on Windows. Thanks, David Jarman. #36
• --ignore patterns are now matched against directory names as well as file names, unless you pass the new --ignore-files-only flag. Thanks, Nick Powell. #30

I use this tool myself on an almost daily basis - it's fantastic for quickly answering questions about code. Recently I've been plugging it into Gemini 2.0 with its 2 million token context length, running recipes like this one:

git clone https://github.com/bytecodealliance/componentize-py
cd componentize-py
files-to-prompt . -c | llm -m gemini-2.0-pro-exp-02-05 \
  -s 'How does this work? Does it include a python compiler or AST trick of some sort?'

I ran that question against the bytecodealliance/componentize-py repo - which provides a tool for turning Python code into compiled WASM - and got this really useful answer.

Here's another example. I decided to have o3-mini review how Datasette handles concurrent SQLite connections from async Python code - so I ran this:

git clone https://github.com/simonw/datasette
cd datasette/datasette
files-to-prompt database.py utils/__init__.py -c | \
  llm -m o3-mini -o reasoning_effort high \
  -s 'Output in markdown a detailed analysis of how this code handles the challenge of running SQLite queries from a Python asyncio application. Explain how it works in the first section, then explore the pros and cons of this design. In a final section propose alternative mechanisms that might work better.'

Here's the result. It did an extremely good job of explaining how my code works - despite being fed just the Python and none of the other documentation. Then it made some solid recommendations for potential alternatives.

I added a couple of follow-up questions (using llm -c) which resulted in a full working prototype of an alternative threadpool mechanism, plus some benchmarks.

One final example: I decided to see if there were any undocumented features in Litestream, so I checked out the repo and ran a prompt against just the .go files in that project:

git clone https://github.com/benbjohnson/litestream
cd litestream
files-to-prompt . -e go -c | llm -m o3-mini \
  -s 'Write extensive user documentation for this project in markdown'

Once again, o3-mini provided a really impressively detailed set of unofficial documentation derived purely from reading the source.

# 14th February 2025, 4:14 am / async, projects, python, sqlite, ai, datasette, webassembly, litestream, generative-ai, llms, ai-assisted-programming, llm, gemini, llm-reasoning, files-to-prompt

shot-scraper 1.6 with support for HTTP Archives. New release of my shot-scraper CLI tool for taking screenshots and scraping web pages.

The big new feature is HTTP Archive (HAR) support. The new shot-scraper har command can now create an archive of a page and all of its dependents like this:

shot-scraper har https://datasette.io/

This produces a datasette-io.har file (currently 163KB) which is JSON representing the full set of requests used to render that page. Here's a copy of that file. You can visualize that here using ericduran.github.io/chromeHAR.

That JSON includes full copies of all of the responses, base64 encoded if they are binary files such as images.

You can add the --zip flag to instead get a datasette-io.har.zip file, containing JSON data in har.har but with the response bodies saved as separate files in that archive.

The shot-scraper multi command lets you run shot-scraper against multiple URLs in sequence, specified using a YAML file. That command now takes a --har option (or --har-zip or --har-file name-of-file), described in the documentation, which will produce a HAR at the same time as taking the screenshots.

Shots are usually defined in YAML that looks like this:

- output: example.com.png
  url: http://www.example.com/
- output: w3c.org.png
  url: https://www.w3.org/

You can now omit the output: keys and generate a HAR file without taking any screenshots at all:

- url: http://www.example.com/
- url: https://www.w3.org/

Run like this:

shot-scraper multi shots.yml --har

Which outputs:

Skipping screenshot of 'https://www.example.com/'
Skipping screenshot of 'https://www.w3.org/'
Wrote to HAR file: trace.har

shot-scraper is built on top of Playwright, and the new features use the browser.new_context(record_har_path=...) parameter.

# 13th February 2025, 9:02 pm / cli, projects, python, scraping, playwright, shot-scraper

llm-gemini 0.4. New release of my llm-gemini plugin, adding support for asynchronous models (see LLM 0.18), plus the new gemini-exp-1114 model (currently at the top of the Chatbot Arena) and a -o json_object 1 option to force JSON output.

I also released llm-claude-3 0.9 which adds asynchronous support for the Claude family of models.

# 18th November 2024, 7:37 am / async, google, plugins, projects, python, ai, generative-ai, llms, llm, anthropic, claude, gemini

LLM 0.18. New release of LLM. The big new feature is asynchronous model support - you can now use supported models in async Python code like this:

import llm

model = llm.get_async_model("gpt-4o")
async for chunk in model.prompt(
    "Five surprising names for a pet pelican"
):
    print(chunk, end="", flush=True)

Also new in this release: support for sending audio attachments to OpenAI's gpt-4o-audio-preview model.

# 17th November 2024, 8:40 pm / async, projects, python, ai, generative-ai, llms, llm

files-to-prompt 0.4. New release of my files-to-prompt tool adding an option for filtering just for files with a specific extension.

The following command will output Claude XML-style markup for all Python and Markdown files in the current directory, and copy that to the macOS clipboard ready to be pasted into an LLM:

files-to-prompt . -e py -e md -c | pbcopy

# 16th October 2024, 11:29 pm / projects, python, llms, files-to-prompt

Datasette 0.65. Python 3.13 was released today, which broke compatibility with the Datasette 0.x series due to an issue with an underlying dependency. I've fixed that problem by vendoring and fixing the dependency and the new 0.65 release works on Python 3.13 (but drops support for Python 3.8, which is EOL this month). Datasette 1.0a16 added support for Python 3.13 last month.

# 7th October 2024, 6:07 pm / projects, python, datasette

simonw/docs cookiecutter template. Over the last few years I’ve settled on the combination of Sphinx, the Furo theme and the myst-parser extension (enabling Markdown in place of reStructuredText) as my documentation toolkit of choice, maintained in GitHub and hosted using ReadTheDocs.

My LLM and shot-scraper projects are two examples of that stack in action.

Today I wanted to spin up a new documentation site so I finally took the time to construct a cookiecutter template for my preferred configuration. You can use it like this:

pipx install cookiecutter
cookiecutter gh:simonw/docs

Or with uv:

uv tool run cookiecutter gh:simonw/docs

Answer a few questions:

[1/3] project (): shot-scraper
[2/3] author (): Simon Willison
[3/3] docs_directory (docs):

And it creates a docs/ directory ready for you to start editing docs:

cd docs
pip install -r requirements.txt
make livehtml

# 23rd September 2024, 9:45 pm / documentation, projects, python, markdown, cookiecutter, sphinx-docs, read-the-docs, uv

Upgrading my cookiecutter templates to use python -m pytest. Every now and then I get caught out by weird test failures when I run pytest and it turns out I'm running the wrong installation of that tool, so my tests fail because that pytest is executing in a different virtual environment from the one needed by the tests.

The fix for this is easy: run python -m pytest instead, which guarantees that you will run pytest in the same environment as your currently active Python.

Yesterday I went through and updated every one of my cookiecutter templates (python-lib, click-app, datasette-plugin, sqlite-utils-plugin, llm-plugin) to use this pattern in their READMEs and generated repositories instead, to help spread that better recipe a little bit further.

# 17th August 2024, 5:12 am / projects, python, pytest, cookiecutter

datasette-python. I just released a small new plugin for Datasette to assist with debugging. It adds a python subcommand which runs a Python process in the same virtual environment as Datasette itself.

I built it initially to help debug some issues in Datasette installed via Homebrew. The Homebrew installation has its own virtual environment, and sometimes it can be useful to run commands like pip list in the same environment as Datasette itself.

Now you can do this:

brew install datasette
datasette install datasette-python
datasette python -m pip list

I built a similar plugin for LLM last year, called llm-python - it's proved useful enough that I duplicated the design for Datasette.

# 12th July 2024, 11:17 pm / plugins, projects, python, datasette

llm-claude-3. I built a new plugin for LLM—my command-line tool and Python library for interacting with Large Language Models—which adds support for the new Claude 3 models from Anthropic.

# 4th March 2024, 6:46 pm / projects, python, ai, generative-ai, llms, llm, anthropic, claude

datasette-studio. I've been thinking for a while that it might be interesting to have a version of Datasette that comes bundled with a set of useful plugins, aimed at expanding Datasette's default functionality to cover things like importing data and editing schemas.

This morning I built the very first experimental preview of what that could look like. Install it using pipx:

pipx install datasette-studio

I recommend pipx because it will ensure datasette-studio gets its own isolated environment, independent of any other Datasette installations you might have.

Now running datasette-studio instead of datasette will get you the version with the bundled plugins.

The implementation of this is fun - it's a single pyproject.toml file defining the dependencies and setting up the datasette-studio CLI hook, which is enough to provide the full set of functionality.

Is this a good idea? I don't know yet, but it's certainly an interesting initial experiment.

# 18th February 2024, 8:38 pm / cli, plugins, projects, pypi, python, datasette

Trogon (via) The latest project from the Textualize/Rich crew, Trogon provides a Python decorator—@tui—which, when applied to a Click CLI application, adds a new interactive TUI mode which introspects the available subcommands and their options and creates a full Text User Interface—with keyboard and mouse support—for assembling invocations of those various commands.

I just shipped sqlite-utils 3.32 with support for this—it uses an optional dependency, so you’ll need to run “sqlite-utils install trogon” and then “sqlite-utils tui” to try it out.

# 21st May 2023, 9:39 pm / cli, projects, python, sqlite-utils

A simple Python implementation of the ReAct pattern for LLMs. I implemented the ReAct pattern (for Reason+Act) described in this paper. It's a pattern where you implement additional actions that an LLM can take - searching Wikipedia or running calculations for example - and then teach it how to request that those actions are run, then feed their results back into the LLM.

# 17th March 2023, 2:52 pm / projects, python, ai, generative-ai, llms, llm-tool-use

click-app. While working on sqlite-generate today I built a cookiecutter template for building the skeleton for Click command-line utilities. It’s based on datasette-plugin so it automatically sets up GitHub Actions for running tests and deploying packages to PyPI.

# 23rd June 2020, 2:21 am / projects, python, cookiecutter

Datasette 0.31. Released today: this version adds compatibility with Python 3.8 and breaks compatibility with Python 3.5. Since Glitch support Python 3.7.3 now I decided I could finally give up on 3.5. This means Datasette can use f-strings now, but more importantly it opens up the opportunity to start taking advantage of Starlette, which makes all kinds of interesting new ASGI-based plugins much easier to build.

# 12th November 2019, 6:11 am / glitch, projects, python, datasette, asgi

json-flatten. A little Python library I wrote that attempts to flatten a JSON object into a set of key/value pairs suitable for transmitting in a query string or using to construct an HTML form. I first wrote this back in 2015 as a Gist—I’ve reconstructed the Gist commit history in a new repository and shipped it to PyPI.

# 22nd June 2019, 4:51 am / json, projects, python