Datasette Apps 0.3a0 improves its Datasette Agent integration
Datasette Apps adds support for hosting and editing custom HTML applications inside Datasette. Such apps can be written by hand, but the release notes say it is easier to create them with LLMs via Datasette Agent. The release, announced on 4 November 2026 by Simon Willison and titled datasette-apps 0.3a0, improves that integration in four ways.
First, apps can now be tagged in Datasette Agent chat messages by typing #. The autocomplete offers the apps the user has permission to view.
Second, two new tools, app_add_stored_queries() and app_remove_stored_queries(), let the agent manage which stored queries an app is allowed to call. Granting a write query requires approval from the user first.
Third, app_create() now checks that each requested stored query exists and that the user can view it. It also asks the user to approve any write queries before the app is created.
Fourth, the "View app" buttons shown by the agent tools, and the links on #app references, now open the app full screen in the Datasette Agent panel.
Key facts
- Datasette Apps hosts and edits custom HTML applications inside Datasette; they can be built by hand or, more easily, with LLMs via Datasette Agent.
- Typing # in a Datasette Agent chat message tags an app, with autocomplete limited to apps the user has permission to view.
- New app_add_stored_queries() and app_remove_stored_queries() tools let the agent manage which stored queries an app may call; granting a write query needs user approval.
- app_create() now verifies that each requested stored query exists and is viewable by the user, and asks for approval of any write queries before creating the app.
- "View app" buttons and #app reference links now open the app full screen in the Datasette Agent panel.
Why it matters
The release is about how an LLM agent gets to act on data. In Datasette Apps, an app can call stored queries, and the agent now has explicit tools to add or remove the queries an app may use. Write queries, which can change data, are gated behind the user's approval, both when granted through the new tools and when an app is first created. The notes frame the whole release as improving the integration between Datasette Apps and Datasette Agent, the easier route to making apps.
Who it affects
People who use Datasette Apps together with Datasette Agent: those who ask the agent to build custom HTML apps over their Datasette data, and those who review and approve what the apps can do. Permissions matter throughout: the # autocomplete lists only apps the user can view, and app_create() checks that the user can view each requested stored query.
How to use it
In a Datasette Agent chat message, type # to tag an app and pick from the autocomplete list. The agent can use app_add_stored_queries() and app_remove_stored_queries() to change which stored queries an app may call, and app_create() will check the requested queries before building the app. Expect an approval prompt for any write query. Clicking a "View app" button or a #app link opens the app full screen in the Datasette Agent panel. No installation instructions are given in the source.
How solid is it
The source is the release announcement itself, a short first-party post by Simon Willison on his blog. It lists the changes but gives no performance figures, user numbers or other metrics. The 0.3a0 version label appears only in the title, not in the body of the post.
Risks and caveats
The notes do not say which LLMs Datasette Agent uses, and they do not mention future plans or when a stable release will arrive. The 0.3a0 label is alpha-style, so details may change. The approval step is the one safeguard the notes describe for write queries; they describe no other protections.
“These can be created by hand, but it's easier to create them using LLMs via Datasette Agent.”
— Datasette Apps release notes, simonwillison.net