auto_open parameter on the Artifact tool / Claude Code v2.1.247

Not switched on

Useful2 Signal4

Artifacts Notable not in their notes

The Artifact tool's auto_open option only appears if server-side config enables Artifact type creation for you.

auto_open with at_create and after_first_write is in the tool schema but spliced in only when server config enables Artifact type creation.

auto_openat_createafter_first_writetype_url

What

The Artifact tool schema accepts auto_open with values at_create and after_first_write, applying only to a create with type_url and no file_path. It is spliced into the schema only when Artifact type creation is enabled for the account by server-side config, so with no server value the parameter is not offered at all.

Details

Passing it alongside file_path is refused with reason auto_open_with_files; passing it without type_url is an input-validation error.
In 2.1.246 the only auto_open strings in the build were unrelated telemetry reasons, so the parameter itself is new.

Evidence

auto_open: un(["at_create", "after_first_write"])

Strings lifted out of the shipped bundle, so the claim above can be checked against them.