Adds a deployment-wide setting to select the computer-use provider
(Anthropic or OpenAI) for AI agents, plus the OpenAI computer-use runner
needed to honor that selection.
The setting is stored in `site_configs` under
`agents_computer_use_provider`, defaults to Anthropic when unset, and is
exposed via experimental GET/PUT endpoints under
`/api/experimental/chats/config/computer-use-provider`. The chatd
computer-use tool now dispatches to either `runAnthropicComputerUse` or
`runOpenAIComputerUse` based on the resolved provider, with
provider-specific result metadata for OpenAI screenshots.
Frontend adds a provider dropdown to the Agents Experiments settings
page nested under the virtual desktop toggle, with disabled state
handling while virtual desktop is off and skeleton loaders while config
queries are in flight.
Hugo and Codex review follow-up:
- Uses shared provider validation and clearer computer-use constant
names.
- Removes stale OpenAI pending-safety-checks commentary.
- Documents why provider result metadata is needed for OpenAI
screenshots.
- Keeps the computer-use subagent visible when provider credentials are
missing, then returns a clear spawn-time configuration error.
- Uses OpenAI's recommended 1600x900 screenshot geometry to preserve the
native 16:9 aspect ratio.
- Moves OpenAI-specific computer-use helpers into
`coderd/x/chatd/chatopenai/computeruse` after rebasing onto the provider
package refactor in `main`.
- Converts OpenAI pixel scroll deltas to Coder desktop wheel-click
amounts.
- Preserves OpenAI pointer modifiers with key down/up desktop actions
and rejects unsupported non-left double-click buttons explicitly.
- Maps OpenAI back/forward side-button clicks to browser navigation key
actions.
- Defaults omitted OpenAI click buttons to left-click.
- Retries mouse release cleanup if the final OpenAI drag release fails.
- Keeps computer-use subagent availability messages stable when provider
config cannot be loaded, while logging the backend error.
- Releases remaining OpenAI modifier keys if a synthetic key-up cleanup
action fails.
- Updates Storybook interaction stories so provider snapshots show the
selected final provider.
> Mux updated this PR description on behalf of Mike.
- **computeruse.go**: Decode base64 screenshot data before storing in
`ToolResponse.Data` (was casting base64 string to bytes without
decoding)
- **chatloop.go**: Re-encode `ToolResponse.Data` to base64 via
`base64.StdEncoding.EncodeToString` instead of `string()` cast
- **mcpclient.go**: UTF-8 validate all text from MCP responses in
`convertCallResult()` using `strings.ToValidUTF8`
- **chatprompt.go (persist)**: Defense-in-depth UTF-8 sanitization of
text and media Text fields before database storage
- **chatprompt.go (replay)**: Antivenom layer that validates base64 and
UTF-8 at read time, auto-healing already-poisoned chats without
requiring a migration
- `TestToolResultAntivenom`: 4 subtests covering poisoned text, poisoned
media, valid media round-trip, and media with invalid UTF-8 text
- Adds `TestConvertCallResult_UTF8Sanitization`: 4 subtests covering invalid
UTF-8 in TextContent, EmbeddedResource, valid passthrough, and
multi-part
- Adds `TestComputerUseTool_Run_ScreenshotDataIsDecodedBinary`: Verifies no
double-encode in the computer-use path
- Updated existing computer-use tests for the new decoded-binary
contract
> 🤖
Agents can already see workspace files and take screenshots, but users could not download those artifacts from chat. This PR adds durable chat attachments to chatd. `attach_file`, explicit `computer` screenshot actions (not the automatic post-action screenshots), and `propose_plan` now fetch bytes over the agent connection, store them in `chat_files`, link them to the chat, and carry attachment metadata in tool responses so `buildAssistantPartsForPersist` can materialize ordinary `type:"file"` assistant parts that the chat file APIs serve.
The same storage helpers are reused for other artifact-producing paths. `wait_agent` recordings and thumbnails are stored as chat files and linked back to the parent chat, with best-effort relinking so parent chats retain those artifacts without leaving orphaned rows when chat-file caps reject links. `storeChatAttachment` wraps insert + link in one transaction, files are capped at 10 MB each and 20 per chat, and serving defaults to `Content-Disposition: attachment` with an explicit inline-safe allowlist.
This PR also consolidates chat-file media policy in `coderd/chatfiles`. Uploads and tool-generated attachments share byte-based MIME detection, SVG blocking, inline-safety rules, and compatible `text/plain` refinement for JSON, CSV, and Markdown. Prompt construction still only inlines synthetic pasted text for model consumption; assistant-created attachments are persisted for the user and intentionally not replayed into later LLM turns.
UI follow-up lives in #24281.
Relates to CODAGT-91
The `ComputerUseProviderTool` function needed a little bit of an
adjustment because I changed `NewComputerUseTool`'s signature in
upstream fantasy a little bit.
- Moves `coderd/chatd/`, `coderd/gitsync/`, `enterprise/coderd/chatd/`
under `x/` parent directories to signal instability
- Adds `Experimental:` glue code comments in `coderd/coderd.go`
> 🤖 This PR was created with the help of Coder Agents, and was
reviewed by my human. 🧑💻
Michael Suchacz