MCP preview after the server lost a session (it expired, or the MCP
process restarted):
- Every server state has an id, made when the state is created. The tab
notices a new id even when the version numbers happen to match, and
every push names the state it was based on, so one based on a lost state
is refused, also when it comes before the tab's first poll (the server
recovers the saved file first).
- The tab keeps the newest canvas XML, saved or not. When the server knows
nothing (no file) or exactly what the tab last saved, the canvas wins and
is saved, so edits made while the server was down are kept. Otherwise
the server's diagram (an AI write the tab missed, a cleared document
that was saved) is shown and the tab's copy goes to History.
- Late answers to an old state's push or poll are dropped; a failed push
says the server is unreachable; Download as .drawio saves the canvas.
Settings and server:
- Saved providers this version does not know stay in storage with their
keys, and sending no longer trips over them.
- The desktop "Ollama (Local)" preset with a key goes to local Ollama
again; a server model's Ollama URL variable is read; the admin panel
writes Ollama Cloud's URL for a key without one.
- Provider error texts show again in the desktop app and for EdgeOne.
- .env: a quoted value followed by a comment ending in a quote is read as
dotenv reads it; unquoted values are unchanged.
- Desktop app: the next launch opens the port where a chat was last
saved; a launch elsewhere that saves nothing does not move it, and a
page with no chats lets the next launch try the other port once.
- The Test button no longer stays busy after another tab changed the key.
- A completed append_diagram is no longer undone by an earlier failed
edit's preview; a file read once in vain is saved again once it is read
or gone.
From the first batch's review:
- The admin panel's Test of an entry without a URL now tests the server's
<P>_BASE_URL, where chat sends the entry's key; chat is unchanged (the
first fix rerouted working setups).
- The model list ends downloads that are too large, accepts answers
without a body, and keeps the "redirects are not allowed" explanation.
- A test covers the preview's History rendering.
- A call the server runs (get_shape_library) still reaches the browser's
tool handler, and it dropped the stored diagram of an earlier broken
edit, whose preview then stayed. Only the tools that draw take it now.
- A display_diagram whose final XML fails the checks loads the diagram
from before its preview again, as a failed edit does.
- After Stop, a tool result that arrives later (a screenshot check still
running) no longer sends a new request; Stop also skips calls the tool
handler already took.
- New chat and opening another chat kept nothing of a diagram drawn
without messages when it could not be saved; now they stay on it.
- The settings dialog drops a model list or test result whose provider
credentials changed meanwhile, also in another tab.
- A saved provider this version does not know crashed the whole page on
load; it is skipped.
- The input emptied a moment after the message showed in the chat, so it
briefly appeared twice (seen as a flaky e2e test).
- The desktop app's preset switch on the same port refetches the server
models instead of reloading the page, which lost unsent attachments.
Found by the second PR review:
- After a streamed edit, an older render of the stream stored the edit's
original diagram again, and the next failed request (no quota, a lost
connection) put that old diagram back on the canvas. The tool handler
now marks its call as handled, so the preview code leaves it alone.
- An edit applied before the UI showed an earlier broken edit's error was
erased when that error undid its preview, or was built on that preview.
The handler now starts from the diagram before all unhandled previews,
and reads the diagram state that updates at once.
- A failed or stopped display_diagram left its half drawn diagram on the
canvas. Its preview is undone now, like an edit's.
- "New chat" cleared a chat that could not be saved (storage full).
- The settings dialog showed a model list, a fetch error or a test result
on the provider that was opened after the request started, and marked a
model id changed during the test as tested.
- A tool call with broken JSON was shown as cut off by the output limit.
- History entries and session thumbnails could pair with a later diagram
when draw.io answered an export late.
- A server model saved before non-ASCII provider names got into the id
was reset to the default model.
Found by the PR review:
- The built-in examples showed a finished card and an empty canvas. They
are answered in the browser, never reach the tool handler, and relied
on the final redraw that an earlier commit removed. The example branch
now loads its diagram itself.
- When the request failed while an edit was streaming (a provider error,
a lost connection), its preview stayed on the canvas. The error handler
now restores the diagram from before the preview.
- The model picker could not scroll with the wheel or touch: the settings
dialog blocks those events outside itself, and the picker is rendered
outside it. The popover is modal now.
- A fetch error and the open picker stayed when switching providers.
- Editing a model id kept the old test warning and response time, which
also hid the "may not be able to draw" hint for the new id.
The "Fetch models" button asks the provider for its models (OpenAI-style
/models, Anthropic, Google, Ollama, OpenRouter, Vercel Gateway, AIHubMix)
and shows them in a searchable picker. This replaces the route that only
worked for AIHubMix.
A snapshot of models.dev (MIT) says which models support tool calls.
Models without them get a "no tool calls" badge in the picker and a hint
in the model list, since drawing needs tool calls. Refresh the snapshot
with scripts/update-model-catalog.mjs.
dayuan.jiang