DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.
Remote sessions now give a more specific error when trying to switch models: "Model picker shows local options in remote sessions — use /model <name> instead" and "Fast mode switching in remote sessions is coming soon — set at session creation for now".
Evidence
Remote model switching (search for "remote-model-picker-unavailable", "Fast mode switching in remote sessions")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.