## Problem
The sidebar diff status (PR icon, +additions/-deletions, file count) was
not updating in real-time. Users had to reload the page to see changes.
Two root causes:
1. **Frontend**: The `diff_status_change` WebSocket handler in
`AgentsPage.tsx` had an early `return` (line 398) that skipped
`updateInfiniteChatsCache`, so the sidebar's cache was never updated.
Even for other event types, the cache merge only spread `status` and
`title` — never `diff_status`.
2. **Server**: `publishChatPubsubEvent` in `chatd.go` constructed a
minimal `Chat` payload without `DiffStatus`, so even if the frontend
consumed the event, `updatedChat.diff_status` would be `undefined`.
## Fix
### Server (`coderd/chatd/chatd.go`)
- `publishChatPubsubEvent` now accepts an optional
`*codersdk.ChatDiffStatus` parameter; when non-nil it's set on the
outgoing `Chat` payload.
- `PublishDiffStatusChange` fetches the diff status from the DB,
converts it, and passes it through.
- Added `convertDBChatDiffStatus` (mirrors `coderd/chats.go`'s converter
to avoid circular import).
- All other callers pass `nil`.
### Frontend (`site/src/pages/AgentsPage/AgentsPage.tsx`)
- Removed the early `return` so `diff_status_change` events fall through
to the cache update logic.
- Added `isDiffStatusEvent` flag and spread `diff_status` into both the
infinite chats cache (sidebar) and the individual chat cache.
Implement the backend for the desktop feature for agents.
- Adds a new `/api/experimental/chats/$id/desktop` endpoint to coderd
which exposes a VNC stream from a
[portabledesktop](https://github.com/coder/portabledesktop) process
running inside the workspace
- Adds a new `spawn_computer_use_agent` tool to chatd, which spawns a
subagent that has access to the `computer` tool which lets it interact
with the `portabledesktop` process running inside the workspace
- Adds the plumbing to make the above possible
There's a follow up frontend PR here:
https://github.com/coder/coder/pull/23006
Handle previously ignored error return values in coderd:
- coderd/chats.go: check sendEvent errors, log on failure
- coderd/chatd/chattest: thread testing.TB through server structs,
replace log.Printf with t.Logf, check writeSSEEvent errors
- coderd/chatd/chattool/createworkspace.go: log UpdateChatWorkspace
failure instead of discarding both return values
- coderd/chatd/chattool/execute.go: surface ProcessOutput error in
the timeout message returned to the caller
- coderd/provisionerdserver: log stream.Send failure in the
DownloadFile error helper
Add cost tracking for LLM chat interactions with microdollar precision.
## Changes
- Add `chatcost` package for per-message cost calculation using
`shopspring/decimal` for intermediate arithmetic
- **Ceil rounding policy**: fractional micros round UP to next whole
micro (applied once after summing all components)
- Database migration: `total_cost_micros` BIGINT column with historical
backfill and `created_at` index
- API endpoints: per-user cost summary and admin rollup under
`/api/experimental/chats/cost/`
- SDK types: `ChatCostSummary`, `ChatCostModelBreakdown`,
`ChatCostUserRollup`
- Fix `modeloptionsgen` to handle `decimal.Decimal` as opaque numeric
type
- Update frontend pricing test fixtures for string decimal types
## Design decisions
- `NULL` = unpriced (no matching model config), `0` = free
- Reasoning tokens included in output tokens (no double-counting)
- Integer microdollars (BIGINT) for storage and API responses
- Price config uses `decimal.Decimal` for exact parsing; totals use
`int64`
Frontend: #23037
Migration 000434 converts chat_messages.role from text to a Postgres
enum, rebuilds the partial index, and adds content_version smallint.
The column is backfilled with DEFAULT 0, then the default is dropped
so future inserts must set it explicitly.
Version 0 uses the role-aware heuristic from #22958. Version 1 (all
new inserts) stores []ChatMessagePart JSON for all roles, including
system messages. ParseContent takes database.ChatMessage directly
and dispatches on version internally. Unknown versions error.
All string(codersdk.ChatMessageRole*) casts at DB write sites are
replaced with database.ChatMessageRole* constants from sqlc.
Refs #22958
File-reference parts in user messages were flattened to `TextContent` at
write time because fantasy has no file-reference content type. The
frontend never saw them as structured parts.
This moves all write paths (user, assistant, tool) from fantasy envelope
format to `codersdk.ChatMessagePart`. The streaming layer (`chatloop`)
is untouched, the conversion happens at the serialization boundary in
`persistStep`.
Old rows are still readable. `ParseContent` uses a structural heuristic
(`isFantasyEnvelopeFormat`) to distinguish legacy envelopes from SDK
parts. We chose this over try/fallback because fantasy envelopes
partially unmarshal into `ChatMessagePart` (the `type` field matches)
while silently losing content. A guard test enforces that no SDK part
can produce the envelope shape.
This is forward-only: new rows are unreadable by old code. Chat is
behind a feature flag so rollback risk is contained.
Also adds a typed `ChatMessageRole` to replace raw strings and
`fantasy.MessageRole*` casts at the persistence boundary. The type
covers `ChatMessage.Role`, `ChatStreamMessagePart.Role`, the
`PublishMessagePart` callback chain, and all DB write sites.
`fantasy.MessageRole*` remains only where we build `fantasy.Message`
structs for LLM dispatch.
Separately, `ProviderMetadata` was leaking to SSE clients via
`publishMessagePart`. `StripInternal` now runs on both the SSE and REST
paths, covering this.
Other cleanup:
- Old `db2sdk.contentBlockToPart` silently dropped metadata on
text/reasoning/tool-call content. New code preserves it.
- `providerMetadataToOptions` now logs warnings instead of silently
returning nil.
- `db2sdk` shrinks from ~250 lines of parallel conversion to ~15 lines
delegating to `chatprompt.ParseContent()`, removing the `fantasy` import
entirely.
Refs #22821
## Problem
Anthropic's API returns a 400 error when `web_search` tool results are
missing:
```
web_search tool use with id srvtoolu_... was found without a corresponding web_search_tool_result block
```
**Root cause:** `persistStep` in `chatd.go` splits ALL
`ToolResultContent` blocks into separate tool-role DB rows.
Provider-executed (PE) tool results like `web_search` must stay in the
assistant message — Anthropic expects `server_tool_use` and
`web_search_tool_result` in the same turn.
The previous fix (#22976) added repair passes to drop PE results during
reconstruction, which fixed cross-step orphans but broke the normal case
(PE result correctly in the same step).
## Fix
Three changes that address the root cause:
1. **`persistStep` (chatd.go):** Check `ProviderExecuted` before
splitting `ToolResultContent` into tool rows. PE results stay in
`assistantBlocks` and are stored in the assistant content column.
2. **`ToMessageParts` (chatprompt.go):** Propagate the
`ProviderExecuted` field to `ToolResultPart` so the fantasy Anthropic
provider can identify PE results and reconstruct the
`web_search_tool_result` block.
3. **Keep existing repair passes** for backward compatibility with
legacy DB data where PE results were incorrectly persisted as separate
tool messages.
## Tests
- `TestProviderExecutedResultInAssistantContent` — PE result stored
inline in assistant content round-trips correctly with
`ProviderExecuted` preserved.
- `TestProviderExecutedResult_LegacyToolRow` — legacy PE results in
tool-role rows are still dropped correctly.
- All existing tests pass (including the 3 PE tests from #22976).
## Problem
1. **Personal behavior prompt not applied**: The chatd background worker
was missing `ActionReadPersonal` on `ResourceUser` in its RBAC subject.
When `resolveUserPrompt` calls `GetUserChatCustomPrompt`, the dbauthz
layer checks `ActionReadPersonal` on the user — which the chatd role
didn't have. The error was silently swallowed (returns `""`), so the
user's custom prompt was never injected into the system messages.
2. **Sequential DB calls on chat startup**: Several independent database
queries in `runChat` and `resolveChatModel` were running sequentially,
adding unnecessary latency before the LLM stream begins.
## Changes
### RBAC fix (`dbauthz.go`)
- Add `rbac.ResourceUser.Type: {policy.ActionReadPersonal}` to
`subjectChatd` site permissions
- This is the minimal permission needed — `ActionRead` on User remains
denied
### Parallelization (`chatd.go`)
Three parallelization points using `errgroup.Group`:
1. **`resolveChatModel`**: `resolveModelConfig` and
`GetEnabledChatProviders` run concurrently (both needed for
`ModelFromConfig`, which stays sequential after the wait)
2. **`runChat` startup**: `resolveChatModel` and
`GetChatMessagesForPromptByChatID` run concurrently (completely
independent)
3. **`runChat` prompt assembly**: `resolveInstructions` and
`resolveUserPrompt` run concurrently (both produce strings;
`InsertSystem` calls maintain correct order after the wait)
Same pattern applied to the `ReloadMessages` callback.
### Test (`dbauthz_test.go`)
- Add assertion in `TestAsChatd/AllowedActions` that
`ActionReadPersonal` on `ResourceUser` is permitted
## What
Adds provider-native web search tools to the chat system. Anthropic,
OpenAI, and Google all offer server-side web search — this wires them up
as opt-in per-model config options using the existing
`ChatModelProviderOptions` JSONB column (no migration).
Web search is **off by default**.
## Config
Set `web_search_enabled: true` in the model config provider options:
```json
{
"provider_options": {
"anthropic": {
"web_search_enabled": true,
"allowed_domains": ["docs.coder.com", "github.com"]
}
}
}
```
Available options per provider:
- **Anthropic**: `web_search_enabled`, `allowed_domains`,
`blocked_domains`
- **OpenAI**: `web_search_enabled`, `search_context_size`
(`low`/`medium`/`high`), `allowed_domains`
- **Google**: `web_search_enabled`
## Backend
- `codersdk/chats.go` — new fields on the per-provider option structs
- `coderd/chatd/chatd.go` — `buildProviderTools()` reads config, creates
`ProviderDefinedTool` entries (uses `anthropic.WebSearchTool()` helper
from fantasy)
- `coderd/chatd/chatloop/chatloop.go` — `ProviderTools` on `RunOptions`,
merged into `Call.Tools`. Provider-executed tool calls skip local
execution. `StreamPartTypeToolResult` with `ProviderExecuted: true` is
accumulated inline (matching fantasy's own agent.go pattern) instead of
post-stream synthesis.
- `coderd/chatd/chatprompt/` — `MarshalToolResult` carries
`ProviderMetadata` through DB persistence so multi-turn round-trips work
(Anthropic needs `encrypted_content` back)
## Frontend
- Source citations render **inline** at the tool-call position (not
bottom-of-message), using `ToolCollapsible` so they look like other tool
cards — collapsed "Searched N results" with globe icon, expand to see
source pills
- Provider-executed tool calls/results are hidden from the normal tool
card UI
- Tool-role messages with only provider-executed results return `null`
(no empty bubble)
- Both persisted (messageParsing.ts) and streaming (streamState.ts)
paths group consecutive `source` parts into a single `{ type: "sources"
}` render block
## Fantasy changes
The fantasy fork (`kylecarbs/fantasy` branch `cj/go1.25`) has the
Anthropic tool code merged in, but will hopefully go upstream from:
https://github.com/charmbracelet/fantasy/pull/163
## Summary
Scale-tested the `chatd` package with mock-based benchmarks to identify
performance bottlenecks. This PR fixes 6 of the 8 identified issues,
ranked by severity.
## Changes
### 1. Parallel tool execution (HIGH) — `chatloop.go`
`executeTools` ran tool calls sequentially. Now dispatches all calls
concurrently via goroutines with `sync.WaitGroup`. Results are
pre-allocated by index (no mutex needed). `onResult` callbacks fire as
each tool completes.
### 2. Pubsub-backed subagent await (HIGH) — `subagent.go`
`awaitSubagentCompletion` polled the DB every 200ms. Now subscribes to
the child chat's `ChatStreamNotifyChannel` via pubsub for near-instant
notifications. Fallback poll reduced to 5s. Falls back to 200ms only
when `pubsub == nil` (single-instance / in-memory).
### 3. Per-chat stream locking (MEDIUM) — `chatd.go`
Replaced single global `streamMu` + `map[uuid.UUID]*chatStreamState`
with `sync.Map` where each `chatStreamState` has its own `sync.Mutex`.
Zero cross-chat contention.
### 4. Batch chat acquisition (MEDIUM) — `chatd.go`
`processOnce` acquired 1 chat per tick. Now loops up to
`maxChatsPerAcquire = 10` per tick, avoiding idle time when many chats
are pending.
### 5. Reduced heartbeat frequency (LOW-MEDIUM) — `chatd.go`
`chatHeartbeatInterval` changed from 30s to 60s. Safe given the 5-minute
`DefaultInFlightChatStaleAfter`.
### 6. O(depth) descendant check (LOW) — `subagent.go`
Replaced top-down BFS (`O(total_descendants)` queries) with bottom-up
parent-chain walk (`O(depth)` queries). Includes cycle protection.
## Not addressed (intentionally)
- Message serialization overhead
- Buffer eviction (`buffer[1:]` pattern)
Adds a `created_by` column (nullable UUID) to the `chat_messages` table
to track which user created each message. Only user-sent messages
populate this field; assistant, tool, system, and summary messages leave
it null.
The column is threaded through the full stack: SQL migration, query
updates, generated Go/TypeScript types, db2sdk conversion, chatd
(including subagent paths), and API handlers. All API handlers that
insert user messages now pass the authenticated user's ID as
`created_by`.
No foreign key constraint was added, matching the existing pattern used
by `chat_model_configs.created_by`.
Adds a user-level custom prompt to the database.
I'll be doing a follow-up for the UI, as we currently do not have
user-level settings (it's just admin). I'll also make it very obvious
for chats where there is a user-level prompt, but I don't know how yet.
Instead of the static 'Agent has finished running.' text, extract a
summary from the last assistant message to give users meaningful context
about what the agent accomplished. Falls back to the static text if no
suitable message is found.
Co-authored-by: Kyle Carberry <kyle@carberry.com>
Fixes https://github.com/coder/internal/issues/1371
## Root causes
Two independent races cause this test to flake at ~2–3/1000:
### 1. Title-generation requests racing with the streaming request
counter
`maybeGenerateChatTitle` fires in a `context.WithoutCancel` goroutine
(line 2130) and makes a **non-streaming** request to the mock OpenAI
handler. The test handler was not filtering by request type, so these
title requests incremented the `requestCount` atomic — throwing off the
coordination logic that uses `requestCount == 1` to identify the first
streaming request and hold it open until shutdown.
**Fix:** Guard the test handler to return a canned response for
non-streaming requests before touching `requestCount`.
### 2. Phantom acquire: `AcquireChat` commits in Postgres but Go sees
`context.Canceled`
During `Close()`, the main loop's `select` can randomly pick
`acquireTicker.C` over `ctx.Done()` (Go spec: when multiple cases are
ready, one is chosen uniformly at random). This calls `processOnce(ctx)`
with an already-canceled context.
In the pq driver, `QueryContext` does **not** check `ctx.Err()` up
front. Instead it calls `watchCancel(ctx)` which spawns a goroutine
monitoring `ctx.Done()`, then sends the query on the existing
connection. When `ctx` is already canceled, a race ensues:
- **pq's watchCancel goroutine** immediately sees `<-done`, opens a
*new* TCP connection to Postgres, and sends a cancel request.
- **The query** is sent concurrently on the existing connection.
Because the `AcquireChat` UPDATE is fast (sub-millisecond, single row
with `SKIP LOCKED`), it often commits before the cancel arrives via the
second connection. Meanwhile in `database/sql`, `initContextClose`
spawns an `awaitDone` goroutine that fires immediately (context is
already canceled), stores `contextDone`, and calls `rs.close(ctx.Err())`
— which races with `Row.Scan` → `rows.Next()`. If `awaitDone` wins,
`Next()` sees `contextDone` is set and returns false, causing Scan to
return `context.Canceled` (or `ErrNoRows`).
**Result:** Postgres committed the UPDATE (chat is now `running` with
serverA's worker ID), but Go sees an error and never spawns a goroutine
to process it. The chat is stuck as `running` with no worker.
If the previous `processChat` cleanup already set the chat back to
`pending`, this phantom acquire flips it back to `running` — which is
exactly what the debug logs showed: after `Close()` returns, the DB
shows `status=running` with serverA's worker ID.
**Fix:** Three guards in `processOnce`:
1. Early `ctx.Err()` check — catches the common case where `select`
picked the ticker after cancellation.
2. `context.WithoutCancel(ctx)` for `AcquireChat` — prevents the pq
`watchCancel` race entirely, ensuring the driver sees the query
result if Postgres executed it.
3. Post-acquire `ctx.Err()` check — if the context was canceled while
`AcquireChat` ran (or between the early check and the call),
immediately release the chat back to `pending`.
## Verification
Passes 2000/2000 iterations (previously flaked at ~2–3/1000):
```
go test -run "TestCloseDuringShutdownContextCanceledShouldRetryOnNewReplica" \
-count=2000 -timeout 1800s -failfast ./coderd/chatd/
```
## Problem
When a chat worker shuts down gracefully (e.g. Kubernetes pod SIGTERM)
while a tool is executing (like `wait_agent` polling for a subagent),
the chat gets stuck in `waiting` status forever — no other worker will
pick it up.
### Root Cause
`persistStep` in `chatd.go` unconditionally returned
`chatloop.ErrInterrupted` for **any** canceled context:
```go
if persistCtx.Err() != nil {
return chatloop.ErrInterrupted // BUG: doesn't check WHY the context was canceled
}
```
During shutdown, the context cause is `context.Canceled` (not
`ErrInterrupted`). But because `persistStep` returned `ErrInterrupted`,
the error handling in `processChat` hit the `ErrInterrupted` check first
(line 2011) and set status to `waiting` — the `isShutdownCancellation`
check (line 2017) was never reached:
```go
// Checked FIRST — matches because persistStep returned ErrInterrupted
if errors.Is(err, chatloop.ErrInterrupted) {
status = database.ChatStatusWaiting // Stuck forever
return
}
// NEVER REACHED during shutdown
if isShutdownCancellation(ctx, chatCtx, err) {
status = database.ChatStatusPending // Would have been correct
return
}
```
### Trigger scenario (from production logs)
1. Chat spawns a subagent via `spawn_agent`, then calls `wait_agent`
2. `wait_agent` blocks in `awaitSubagentCompletion` polling loop
3. Worker pod receives SIGTERM → `Close()` cancels server context
4. Context cancellation propagates to `awaitSubagentCompletion` →
returns `context.Canceled`
5. Tool execution completes, `persistStep` is called with canceled
context
6. `persistStep` returns `ErrInterrupted` (wrong!) → status set to
`waiting` (stuck!)
## Fix
Check `context.Cause()` before deciding which error to return:
```go
if persistCtx.Err() != nil {
if errors.Is(context.Cause(persistCtx), chatloop.ErrInterrupted) {
return chatloop.ErrInterrupted // Intentional interruption
}
return persistCtx.Err() // Shutdown → context.Canceled
}
```
This preserves `context.Canceled` for shutdown, allowing
`isShutdownCancellation` to match and set status to `pending` so another
worker retries the chat.
## Test
Added `TestRun_ShutdownDuringToolExecutionReturnsContextCanceled` which:
1. Streams a tool call to a blocking tool (simulating `wait_agent`)
2. Cancels the server context (simulating shutdown) while the tool
blocks
3. Verifies `Run` returns `context.Canceled`, NOT `ErrInterrupted`
## Bug
After compaction in the chat loop, the loop re-enters and calls the LLM
with a prompt that has **no non-system messages**. Anthropic (and most
providers) require at least one user/assistant/tool message, so the API
errors with empty messages.
## Root Cause
The compaction summary was stored as `role=system`. After compaction,
`GetChatMessagesForPromptByChatID` returns only:
- The compressed system summary (matched by the CTE)
- Original non-compressed system messages (system prompts)
All original user/assistant/tool messages are excluded (they predate the
summary). The compaction assistant/tool messages are `compressed=TRUE`
and don't match the main query's `compressed=FALSE` clauses.
So `ReloadMessages` returned only system messages. The Anthropic
provider moves system messages into a separate `system` field, leaving
the `messages` API field as `[]`.
## Fix
1. **Changed compaction summary from `role=system` to `role=user`** —
the summary now appears as a user message in the reloaded prompt, giving
the model valid conversational context to respond to.
2. **Simplified the CTE** — removed the `role = 'system'` check and
narrowed `visibility IN ('model', 'both')` to just `visibility =
'model'`. The summary is the only compressed message with
`visibility=model` (the assistant has `visibility=user`, the tool has
`visibility=both`), so the role check was redundant.
## Test
`PostRunCompactionReEntryIncludesUserSummary`: verifies the re-entry
prompt contains a user message (the compaction summary) after compaction
+ reload.
## Problem
When `message_agent` is called with `interrupt=true`, two independent
code paths race to persist messages:
1. `SendMessage` inserts the **user message** into `chat_messages` at
time T1
2. `persistInterruptedStep` saves the partial **assistant response** at
time T2 (T2 > T1)
Since `chat_messages` are ordered by `(created_at, id)`, the assistant
message ends up **after** the user message that triggered the interrupt.
On reload, this produces a broken conversation where the interrupted
response appears below the new user message — and Anthropic rejects the
trailing assistant message as unsupported prefill.
The root cause is that **two independent writers can't guarantee
ordering**. Any solution involving timestamp manipulation or
signal-then-wait coordination leaves race windows.
## Fix
Route interrupt behavior through the existing queued message mechanism:
1. `SendMessage` with `BusyBehaviorInterrupt` now inserts into
`chat_queued_messages` (not `chat_messages`) when the chat is busy
2. After queuing, `setChatWaiting` signals the running loop to stop
3. The deferred cleanup in `processChat` persists the partial assistant
response first, then auto-promotes the queued user message
This eliminates the race entirely: the assistant partial response and
user message are written by the same serialized cleanup flow, so
ordering is guaranteed by the DB's auto-incrementing `id` sequence. No
timestamp hacks, no reordering at send time.
Supersedes #22728 — fixes the root cause instead of reordering at prompt
construction time.
Split from #22693 per review feedback.
Fixes multiple bugs in coderd/chatd and sub-packages including race
conditions, transaction safety, stream buffer bounds, retry limits, and
enterprise relay improvements.
See commit message for full list.
This change adds support for image attachments to chat via add button
and clipboard paste. Files are stored in a new `chat_files` table and
referenced by ID in message content. File data is resolved from storage
at LLM dispatch time, keeping the message content column small.
Upload validates MIME types via content type or content sniffing against
an allowlist (png, jpeg, gif, webp). The retrieval endpoint serves files
with immutable caching headers. On the frontend, uploads start eagerly
on attach with a background fetch to pre-warm the browser HTTP cache so
the timeline renders instantly after send.
Adds real-time git status watching for workspace agents, so the frontend
can subscribe over WebSocket and show
git file changes in near real-time.
1. Subscription is scoped to a **chat** via `GET
/api/experimental/chats/{chat}/git/watch`.
2. The workspace agent automatically determines which paths to watch
based on tool calls made by the chat (and its ancestor chats).
3. Workspace agent polls subscribed repo working trees on a 30s
interval, on tools calls, and on explicit `refresh` from the client.
4. Scans are rate-limited to at most once per second.
5. Edited paths are tracked **in-memory** inside the workspace agent.
There is no database persistence — state is lost on agent restart. This
will be addresses in a future PR.
6. Messages sent over WebSocket include a full-repo snapshot (unified
diff, branch, origin). A new message is emitted only when the snapshot
changes.
This PR was implemented with AI with me closely controlling what it's
doing. The code follows a plan file that was updated continuously during
implementation. Here's the file if you'd like to see it:
[project.md](https://gist.github.com/hugodutka/8722cf80c92f8a56555f7bc595b770e2).
It reflects the current state of the PR.
## Summary
When a chat's workspace is stopped, the LLM previously had no way to
start it — `create_workspace` would either create a duplicate workspace
or fail. This adds a dedicated `start_workspace` tool to the agent flow.
## Changes
### New: `start_workspace` tool
(`coderd/chatd/chattool/startworkspace.go`)
- Detects if the chat's workspace is stopped and starts it via a new
build with `transition=start`
- Reuses the existing `waitForBuild` and `waitForAgent` helpers (shared
logic)
- Shares the workspace mutex with `create_workspace` to prevent races
- Idempotent: returns immediately if the workspace is already running or
building
- Returns a `no_agent` / `not_ready` status if the agent isn't available
yet (non-fatal)
### Updated: `create_workspace` stopped-workspace hint
- `checkExistingWorkspace` now returns a `stopped` status with message
`"use start_workspace to start it"` when it detects the chat's workspace
is stopped, instead of falling through to create a new workspace
### Wiring
- `chatd.Config` / `chatd.Server`: new `StartWorkspace` /
`startWorkspaceFn` field
- `coderd/chats.go`: new `chatStartWorkspace` method that calls
`postWorkspaceBuildsInternal` with proper RBAC context
- `coderd/coderd.go`: passes `chatStartWorkspace` into chatd config
- Tool registered alongside `create_workspace` for root chats only (not
subagents)
### Tests (`startworkspace_test.go`)
- `NoWorkspace`: error when chat has no workspace
- `AlreadyRunning`: idempotent return for workspace with successful
start build
- `StoppedWorkspace`: verifies StartFn is called, build is waited on,
and success response returned
When a user interrupts a chat, the status transitions to `waiting` which
previously triggered an "Agent has finished running." web push
notification. This is incorrect — the user interrupted it themselves, so
no notification is needed.
## Changes
### `coderd/chatd/chatd.go`
- Added `wasInterrupted` flag alongside the existing `status` variable
- Set the flag when `ErrInterrupted` is detected in the error handler
- Added `!wasInterrupted` to the web push dispatch condition
### `coderd/chatd/chatd_test.go`
- Added `TestInterruptChatDoesNotSendWebPushNotification` that creates a
chat with a mock webpush dispatcher, processes it, interrupts it, and
verifies no push notification was dispatched
- Added `mockWebpushDispatcher` implementing the `webpush.Dispatcher`
interface
## Problem
Three bugs with chat summarization (compaction) share a single root
cause: `ReloadMessages` was never wired up in the production
`chatloop.Run()` call.
### Bug 1: Compaction never fires between steps
The inline compaction guard in `chatloop.go` requires both `Compaction`
and `ReloadMessages` to be non-nil:
```go
if opts.Compaction != nil && opts.ReloadMessages != nil {
```
Since `ReloadMessages` was only set in tests, inline compaction was
**dead code in production**. Long multi-step turns could blow through
the context window.
### Bug 2: Compaction only occurs at end of turn
The post-run safety net doesn't check `ReloadMessages`, so it was the
only compaction path that fired:
```go
if !alreadyCompacted && opts.Compaction != nil { // no ReloadMessages check
```
This meant compaction only happened once, after the entire agent turn
finished.
### Bug 3: Agent stops after summarization
After post-run compaction, `Run()` unconditionally returned `nil`.
`processChat` then set the chat status to `waiting` (done). The agent
never had a chance to continue with its fresh summarized context.
## Fix
1. **Wire up `ReloadMessages`** in `chatd.go`: reloads persisted
messages from the database and re-applies system prompts (subagent
instruction, workspace AGENTS.md).
2. **Wrap the step loop in an outer compaction loop**: when compaction
fires on the model's final step (`compactedOnFinalStep`), reload
messages and `continue` the outer loop so the agent re-enters with
summarized context.
3. **Track `compactedOnFinalStep`** to distinguish inline compaction on
the last step (needs re-entry) from inline compaction mid-loop followed
by more tool-call steps (agent already consumed the compacted context,
no re-entry needed).
4. **Add `maxCompactionRetries = 3`** to prevent infinite compaction
loops.
## Testing
- All 7 existing compaction tests pass unchanged.
- Added `PostRunCompactionReEntersStepLoop` test: verifies that when a
text-only response triggers compaction, the outer loop re-enters and the
agent makes a second stream call with fresh context.
## Summary
Fixes a bug where interrupting a streaming chat and sending a new
message
left the relay connected to the wrong replica. Expanded into a broader
refactor that cleanly separates concerns:
- **OSS** owns pubsub subscription, message catch-up, queue updates,
status forwarding, and local parts merging.
- **Enterprise** (`enterprise/coderd/chatd`) only manages relay dialing,
reconnection, and stale-dial discarding for cross-replica streaming.
## Architecture
### OSS `coderd/chatd/chatd.go`
`Subscribe()` builds the initial snapshot then runs a single merge
goroutine that handles:
- Pubsub subscription for durable events (status, messages, queue,
errors)
- Message catch-up via `AfterMessageID`
- Local `message_part` forwarding
- Relay events from enterprise (when `SubscribeFn` is set)
- Sends `StatusNotification` to enterprise so it can manage relay
lifecycle
Key types:
- `SubscribeFn` — enterprise hook, returns relay-only events channel
- `SubscribeFnParams` — `ChatID`, `Chat`, `WorkerID`,
`StatusNotifications`, `RequestHeader`, `DB`, `Logger`
- `StatusNotification` — `Status` + `WorkerID`, sent to enterprise on
pubsub status changes
### Enterprise `enterprise/coderd/chatd/chatd.go`
`NewMultiReplicaSubscribeFn(cfg MultiReplicaSubscribeConfig)` returns a
`SubscribeFn` that:
- Opens an initial synchronous relay if the chat is running on a remote
worker
- Reads `StatusNotifications` from OSS to open/close relay connections
- Handles async dial, reconnect timers, stale-dial discarding
- Returns only relay `message_part` events
## Bug fixes
### Original bug: stale relay dial after interrupt
`openRelayAsync` goroutines used `mergedCtx` (subscription-level), not a
per-dial context. `closeRelay()` could not cancel in-flight dials. When
the user interrupts and a new replica picks up the chat, the old dial
goroutine could complete after the new one and deliver a stale
`relayResult`.
**Fix**: per-dial `dialCtx`/`dialCancel`, `expectedWorkerID` tracking,
`workerID` on `relayResult`. `closeRelay()` cancels the dial context and
drains `relayReadyCh`. Merge loop rejects mismatched worker IDs.
### Additional fixes
- `statusNotifications` send-on-closed-channel race — goroutine now owns
`close()` via defer
- Enterprise spin-loop on `StatusNotifications` close — two-value
receive
with nil-out
- `hasPubsub` set from `p.pubsub != nil` instead of subscription success
— now tracks actual subscription result
- `lastMessageID` not initialized from `afterMessageID` — caused
duplicate messages on catch-up
- `wrappedParts` goroutine leaked remote connection on `dialCtx` cancel
- `closeRelay()` did not drain `relayReadyCh`
- `setChatWaiting` race with `SendMessage(Interrupt)` — wrapped in
`InTx`
- `processChat` post-TX side effects fired when chat was taken by
another
worker — added `errChatTakenByOtherWorker` sentinel
- Cancel closure data race on `reconnectTimer`
- Bare blocking send on pubsub error path
- `localParts` hot-spin after channel close
- No-pubsub branch dropped relay events and initial snapshot
- Failed relay dial caused permanent stall (no reconnect retry)
- DB error during reconnect timer caused permanent stall
- `time.NewTimer` replaced with `quartz.Clock` for testable timing
## Tests
9 enterprise tests covering:
- Relay reconnect on drop (mock clock)
- Async dial does not block merge loop
- Relay snapshot delivery
- Stale dial discarded after interrupt
- Cancel during in-flight dial
- Running-to-running worker switch
- Failed dial retries (mock clock)
- Local worker closes relay
- Multiple consecutive reconnects (mock clock)
All pass with `-race`.
## Problem
Title generation uses the same model the user selected for chat. This
breaks when:
1. **Thinking/extended thinking models** — `ToolChoice: None` conflicts
with extended thinking on Anthropic. The bare call has no thinking
config, so provider-level defaults can conflict.
2. **Expensive models** — User picks `o3` or `claude-opus-4`, and a
trivial 8-word title generation burns through tokens/cost unnecessarily.
3. **Provider quirks** — Different providers have different constraints
around thinking mode + tool choice combinations.
## Solution
Modeled after how `coder/mux` handles this with
`NAME_GEN_PREFERRED_MODELS` + ordered candidate fallback:
### Phase 1: Candidate model list with fallback
- New `TitleModelFunc` type returns an ordered list of candidate models
- Tries `claude-haiku-4-5` → `gpt-4o-mini` → user's model
- Gracefully skips unavailable candidates (missing API key, provider not
configured)
- Falls back to the user's chat model as last resort
### Phase 2: Provider-safe call options
- Removed `ToolChoice: None` which conflicts with extended thinking on
some providers
- Added `MaxOutputTokens: 256` to cap token usage
- Improved title prompt with verb-noun format guidance (`Fix sidebar
layout`, `Add user authentication`) and explicit
no-markdown/no-code-fences instructions
### Files changed
- `coderd/chatd/title.go` — Candidate loop, improved prompt, safe call
options
- `coderd/chatd/chatd.go` — Build `TitleModelFunc` closure with
lightweight candidates
## Summary
Subagent (child) chats were previously given access to workspace
provisioning tools (`list_templates`, `read_template`,
`create_workspace`), which could lead to uncontrolled resource
consumption. This PR moves those tools behind the same
`!chat.ParentChatID.Valid` gate that already protects the subagent tools
(`spawn_agent`, `wait_agent`, etc.).
## Changes
- **`coderd/chatd/chatd.go`**: Moved `list_templates`, `read_template`,
and `create_workspace` tool registration into the root-chat-only block
alongside subagent tools.
- **`coderd/chatd/chatd_test.go`**: Added
`TestSubagentChatExcludesWorkspaceProvisioningTools` — an E2E test that
spawns a subagent via a root chat and verifies the subagent's LLM call
does not include workspace provisioning or subagent tools.
- **`coderd/chatd/chattest/openai.go`**: Added `Tools` field to
`OpenAIRequest` and supporting `OpenAITool`/`OpenAIToolFunction` types
so tests can inspect which tools are sent to the model.
## Problem
Two bugs in the agents chat flow:
1. **Optimistic rendering glitch**: When sending a message while the
agent is busy, a fake message with a negative ID appears in the
timeline, then gets rolled back to the queued state. This causes a
jarring flash.
2. **Auto-promoted messages not appearing**: When the server
auto-promotes a queued message after finishing a task, the promoted user
message doesn't show up in the timeline until the LLM finishes its
response.
## Root Causes
**Bug 1**: The optimistic rendering system injected placeholder messages
with `id: -Date.now()` into the store. When the server responded with
`queued: true`, the optimistic message was rolled back — but the user
had already seen it flash in the timeline.
**Bug 2**: In `processChat`'s deferred cleanup, the auto-promoted
message was published via `publishEvent()`, which only delivers to local
in-process stream subscribers. The SSE subscriber goroutine only
forwards `message_part` events from the local channel — it ignores
`message` events. Durable events reach the SSE client via pubsub → DB
read, but `publishEvent` doesn't trigger a pubsub notification. The
explicit `PromoteQueued` endpoint correctly used `publishMessage()`
(which does both), but the auto-promote path did not.
## Changes
### Frontend (`site/`)
- **AgentDetail.tsx**: Remove optimistic message injection from send and
edit flows. Instead, use the `CreateChatMessageResponse.message` from
the POST response to insert the real server message into the store
immediately.
- **ChatContext.ts**: Remove the negative-ID cleanup logic from
`upsertDurableMessage` that stripped optimistic placeholders when real
messages arrived.
- **chatStore.test.ts**: Remove 2 tests for negative-ID optimistic
message behavior.
### Backend (`coderd/chatd/`)
- **chatd.go**: In `processChat` cleanup, replace `publishEvent()` with
`publishMessage()` for auto-promoted messages. This ensures the pubsub
notification (`AfterMessageID`) is sent, so SSE subscribers read the new
message from the DB immediately.
## Problem
There is a race condition in the chat stream reconnect path. When a
client connects (or reconnects) to `/stream`, sometimes they only see a
`status: running` event but never receive any `message_part` events —
the stream appears stuck.
## Root Cause
In `processChat`, the sequence is:
1. `publishStatus(running)` — broadcasts `status: running` to all
subscribers and via pubsub.
2. `runChat()` is called.
3. Inside `runChat`, there's significant setup work (model resolution,
DB queries, title generation, prompt building, instruction resolution).
4. Only **after** all that setup does `runChat` set `buffering = true`
on the stream state.
If a client connects to `/stream` between steps 1 and 4:
- `Subscribe()` reads `chat.Status == running` from the DB, so it
includes `status: running` in the snapshot.
- But `buffering` is still `false`, so `subscribeToStream` returns an
**empty** local snapshot (no message_parts).
- `publishToStream` **drops** all `message_part` events when `buffering`
is false.
- Result: client sees `running` but never gets any streaming content.
## Fix
Move the `buffering = true` setup (and its deferred cleanup) from
`runChat` into `processChat`, right before `publishStatus(running)`.
This guarantees the buffer is active before any subscriber can observe
`status: running`, so:
- The snapshot always includes any in-flight `message_part` events.
- `publishToStream` never drops parts because buffering is already on.
## Problem
Flaky test:
`TestCloseDuringShutdownContextCanceledShouldRetryOnNewReplica`
(coder/internal#1371)
The test intermittently fails because the chat ends up in `waiting`
status instead of `pending` after server shutdown.
## Root Cause
There is a race condition in `processChat` where `runChat` completes
successfully just as the server context is being canceled during
`Close()`. The sequence:
1. Server calls `Close()`, canceling the server context.
2. The LLM HTTP response has already been fully written by the mock
server (the stream closes normally before context cancellation
propagates to the HTTP client).
3. `runChat` returns `nil` (success) instead of `context.Canceled`.
4. The existing `isShutdownCancellation` check only runs when `runChat`
returns an error, so the shutdown is not detected.
5. `processChat`'s deferred cleanup marks the chat as `waiting` instead
of `pending`.
6. The test's assertion that the chat is `pending` never becomes true.
This race is timing-dependent — it only triggers when the mock server's
HTTP response completes in the narrow window between context
cancellation being initiated and it propagating through the HTTP
transport layer.
## Fix
Add a server context check after `runChat` returns successfully. If the
server is shutting down (`ctx.Err() != nil`), override the status to
`pending` so another replica can pick up the chat.
This is the same pattern already used for the error path
(`isShutdownCancellation`), extended to cover the success path.
## Problem
When the git askpass flow triggered diff status refreshes, it updated
**every chat** connected to the workspace. This was wasteful and could
cause confusing status updates on unrelated chats.
## Solution
Thread the chat ID through the entire git askpass flow so only the chat
that initiated the git operation gets updated:
1. **`coderd/chatd/chattool/execute.go`** — Sets `CODER_CHAT_ID` env var
on spawned processes (alongside the existing `CODER_CHAT_AGENT`)
2. **`cli/gitaskpass.go`** — Reads `CODER_CHAT_ID` from the environment
and sends it as a `chat_id` query parameter in the `ExternalAuthRequest`
3. **`codersdk/agentsdk/agentsdk.go`** — Adds `ChatID` field to
`ExternalAuthRequest` and encodes it as a query param
4. **`coderd/workspaceagents.go`** — Parses `chat_id` query param and
passes it through to `storeChatGitRef` and
`triggerWorkspaceChatDiffStatusRefresh`
5. **`coderd/chats.go`** — `storeChatGitRef` and
`refreshWorkspaceChatDiffStatuses` now scope updates to just the
initiating chat when a chat ID is provided, falling back to
all-workspace-chats behavior for backwards compatibility (non-chat git
operations)
## Problem
Subscribers connecting to a different replica than the one running the
chat see full messages appear but no streaming partials (`message_part`
events). The relay mechanism that forwards ephemeral parts across
replicas had several bugs.
## Root Causes
1. **`openRelay()` blocked the event loop** — The WebSocket dial (TCP +
TLS + HTTP upgrade) to the worker replica ran synchronously inside the
select loop. While dialing, no events could be processed, channels
filled up, and parts were silently dropped.
2. **Relay drops were permanent** — When the relay WebSocket closed
mid-stream, `relayParts` was set to nil and never reopened. No status
notification would re-trigger it since the chat was still running on the
same worker.
3. **`drainInitial` snapshot race** — The `default` case in the initial
drain loop caused the snapshot to be empty if the remote hadn't flushed
data yet (common immediately after WebSocket connect).
4. **Duplicate event delivery** — The `preloaded` slice caused snapshot
events to be sent both in the return value and re-sent through the
channel goroutine.
## Fixes
### `coderd/chatd/chatd.go` (Subscribe method)
- **Async relay dial**: `openRelayAsync()` spawns a goroutine to dial
the remote replica. The result (channel + cancel func) is delivered on a
`relayReadyCh` channel that the select loop reads without blocking.
- **Relay reconnection**: When the relay channel closes, a 500ms timer
fires. The handler re-checks chat status from the DB and reopens the
relay if the chat is still running on a remote worker.
- **Snapshot parts via channel**: Relay snapshot + live parts are
wrapped into a single channel so they flow through the same path,
avoiding races with the select loop.
### `enterprise/coderd/chats.go` (newRemotePartsProvider)
- **Timer-based drain**: Replaced `default` with a 1-second timer. After
the first event, `Reset(0)` switches to non-blocking drain for remaining
buffered events.
- **Remove preloaded duplication**: The goroutine now only forwards new
events; snapshot events are returned to the caller directly.
## Testing
All existing tests pass:
- `TestInterruptChatBroadcastsStatusAcrossInstances`
- `TestSubscribeSnapshotIncludesStatusEvent`
- `TestSubscribeNoPubsubNoDuplicateMessageParts`
- `TestSubscribeAfterMessageID`
- `TestChatStreamRelay/RelayMessagePartsAcrossReplicas`
## Problem
The pubsub notification handler in `chatd` re-fetched **all** messages
from the DB on every new message notification, then filtered in Go with
`msg.ID > lastMessageID`. This grows linearly with conversation length —
every new message triggers a full table scan of that chat's history.
The `AfterMessageID` field in the pubsub notification payload was
clearly designed for cursor-based fetching, but no matching query
existed.
## Fix
- Add `GetChatMessagesByChatIDAfter` SQL query with `WHERE id >
@after_id`, so the database does the filtering instead of Go.
- Use it in the pubsub notification handler in `chatd.go`, passing
`lastMessageID` as the cursor.
- Implement the dbauthz wrapper (was a `panic("not implemented")` stub
from codegen) with the same read-check-on-parent-chat pattern as
adjacent methods.
- Add dbauthz test coverage for the new method.
**Not changed:** The initial snapshot in `Subscribe()` still loads all
messages — that's correct, since a newly-connecting client needs the
full conversation state. The waste was only in the ongoing notification
path.
## Problem
When archiving an agent with subagents, the children briefly flash in
the sidebar as root-level items before disappearing. Two issues:
1. **Backend:** Archive used N+1 queries — a recursive DFS
(`archiveChatTree`, no transaction) or BFS loop (`chatd.ArchiveChat`,
N+1 queries in a tx) to walk the tree and archive each chat
individually.
2. **Frontend:** The SSE `deleted` event handler only filtered out the
parent chat from the cache. Children remained briefly, got promoted to
root-level by `buildChatTree`, then disappeared on the next re-fetch.
## Fix
**Backend:** Replace both tree-walk implementations with a single SQL
query:
```sql
UPDATE chats SET archived = true, updated_at = NOW()
WHERE id = @id OR root_chat_id = @id;
```
This leverages the existing `root_chat_id` column (already indexed) to
archive the entire tree atomically.
**Frontend:** When a `deleted` event arrives, also filter out any chats
whose `root_chat_id` matches the deleted chat, so children vanish from
the sidebar immediately with the parent.
## Changes
- `coderd/database/queries/chats.sql` — Added `ArchiveChatTreeByID`
query
- `coderd/chats.go` — Use single query, delete `archiveChatTree`
function
- `coderd/chatd/chatd.go` — Simplify `ArchiveChat` to use single query
- `coderd/database/dbauthz/dbauthz.go` — Auth wrapper for new query
- `coderd/chats_test.go` — Added `TestArchiveChat/ArchivesChildren`
subtest
- `site/src/pages/AgentsPage/AgentsPage.tsx` — Filter children in SSE
handler
- Generated files updated via `make gen`
Add a new SubjectTypeChatd RBAC subject with minimal permissions:
- Chat: CRUD
- Workspace: Read
- DeploymentConfig: Read
Replace all 10 AsSystemRestricted calls in coderd/chatd/chatd.go:
- Line 890: Use AsChatd instead of AsSystemRestricted for the background
processor context.
- Subscribe() path (5 calls): Remove system escalation entirely; these
run under the authenticated user's context from the HTTP handler.
- processChat path (4 calls): Remove redundant per-call wraps; the
context already carries AsChatd from the processor start.
Add TestAsChatd verifying allowed and denied actions.
Created using Mux (Opus 4.6)
## Summary
Wire VAPID web push notifications into the Agents (chat) system so users
get desktop notifications when an agent finishes running.
### Backend
- Add `webpush.Dispatcher` to `chatd.Server` and pass it through from
`coderd.Options.WebPushDispatcher`
- In `processChat()`'s deferred cleanup, dispatch a web push
notification when the chat reaches a terminal state:
- **`waiting`** (success): "Agent has finished running."
- **`error`** (failure): the error message, or "Agent encountered an
error."
- Sub-agent chats (`ParentChatID.Valid`) are skipped to avoid
notification spam from internal delegation
- Gracefully no-ops when the dispatcher is nil (web push disabled)
### Frontend
- New `WebPushButton` component — a bell icon that uses the existing
`useWebpushNotifications` hook
- Returns `null` when the `web-push` experiment is off
- Three states: loading spinner, green bell (subscribed), muted bell-off
(unsubscribed)
- Tooltip + toast feedback on toggle
- Added to both the Agents page empty state top bar and the AgentDetail
top bar
- The Agents page has its own layout (no standard Navbar), so it needs
its own subscribe button
### End-to-end flow
1. User clicks the bell icon on `/agents` → browser subscribes via VAPID
2. User starts an agent chat → chat enters `running` status
3. Agent finishes → `processChat` defer sets status to `waiting`/`error`
→ dispatches web push
4. Browser service worker shows a desktop notification with the chat
title and status
---------
Co-authored-by: Coder <coder@users.noreply.github.com>
## Problem
Chat titles sometimes don't update in the UI. The generated AI title
gets stuck as the fallback (first 6 words of the message) even though
the backend successfully generates a proper title.
## Root Causes
### 1. Cancelable context used during cleanup DB read (P0)
In `processChat`, the deferred cleanup re-reads the chat from the DB to
pick up the AI-generated title for the `status_change` pubsub event. But
it used the cancelable `ctx` instead of `cleanupCtx`:
```go
// Before — ctx may already be canceled here
if freshChat, readErr := p.db.GetChatByID(ctx, chat.ID); readErr == nil {
```
When the context is canceled, the DB read fails silently and the
`status_change` event carries the stale fallback title.
### 2. Title goroutine not tracked by inflight WaitGroup (P2)
The `maybeGenerateChatTitle` goroutine was fire-and-forget — not tracked
by `p.inflight`. During graceful shutdown, the server could exit before
the goroutine completes its DB write or pubsub publish.
### 3. No recovery when watchChats() WebSocket misses events
The frontend relies entirely on the `watchChats()` SSE connection for
title updates. If the connection drops or misses events, titles never
recover — the only fix was a full page reload.
## Fixes
1. **Use `cleanupCtx`** for the `GetChatByID` call and logger in the
deferred cleanup block.
2. **Track the title goroutine** with `p.inflight.Add(1)` / `defer
p.inflight.Done()` so shutdown waits for it.
3. **Invalidate chats query** on WebSocket open/close/error events so
missed updates are recovered via refetch. Also enable
`refetchOnWindowFocus` for the chats query.
Co-authored-by: Coder <coder@users.noreply.github.com>
When a chatd server shuts down (`Close()`), the server context is
canceled. Previously, in-flight chats would be marked as `error` because
the `context.Canceled` error was not distinguished from actual
processing failures.
This adds `isShutdownCancellation()` to detect when the error is caused
by the server context being canceled (as opposed to a chat-specific
cancellation like `ErrInterrupted`). When detected, the chat status is
set to `pending` with no `last_error`, allowing another replica to pick
it up and retry.
Extracted from #22440 — only the context cancellation bug fix, no
chattest changes.
The in-memory stream buffer accumulated message-part events for the
entire duration of a chat run. Late-joining subscribers received all
buffered parts even though the backing messages had already been
committed to the database, wasting memory and potentially duplicating
content.
Clear the buffer at the end of each `persistStep` call so that only
in-flight (uncommitted) parts remain in the buffer.
## Summary
Remove the `workspace_agent_id` column from the `chats` table and
dynamically look up the first workspace agent instead.
## Problem
When a workspace is stopped and restarted, the workspace agent gets a
new ID. The `workspace_agent_id` stored on the chat at creation time
becomes stale, making the agent unreachable. This caused chats to break
after workspace restarts.
## Solution
Instead of persisting the agent ID, dynamically look up the first agent
from the workspace's latest build via
`GetWorkspaceAgentsInLatestBuildByWorkspaceID` whenever an agent
connection is needed. The `workspace_id` on the chat remains stable
across restarts.
This behavior may be refined later (e.g., agent selection heuristics),
but picking the first agent resolves the immediate breakage.
## Changes
- **Migration 000425**: Drop `workspace_agent_id` column from `chats`
- **SQL queries**: Remove `workspace_agent_id` from `InsertChat` and
`UpdateChatWorkspace`
- **chatd.go**: `getWorkspaceConn` and `resolveInstructions` now look up
agents dynamically from workspace ID
- **chatd.go**: Remove `refreshChatWorkspaceSnapshot` (no longer needed)
- **createworkspace.go**: Stop persisting agent ID when associating
workspace with chat
- **subagent.go**: Stop passing agent ID to child chats
- **SDK/frontend**: Remove `WorkspaceAgentID` / `workspace_agent_id`
from Chat type
---------
Co-authored-by: Kyle Carberry <kylecarbs@gmail.com>
Two changes:
1. **Gate subagent tools behind `!chat.ParentChatID.Valid`** so child
agents never receive `spawn_agent`, `wait_agent`, `message_agent`, or
`close_agent`. Previously all 4 tools were given to every chat.
`spawn_agent` would fail at runtime ("delegated chats cannot create
child subagents") but the other 3 had no guard at all — meaning a child
could theoretically operate on sibling chats. Removing the tools
entirely is cleaner and saves context window.
2. **Rewrite tool descriptions to explain *when* to use them**, not just
what they do. `spawn_agent` now says to use it for clearly scoped,
independent, self-contained tasks (e.g. fixing a specific bug, writing a
single module, running a migration) and explicitly says *not* to use it
for simple operations you can handle with
`execute`/`read_file`/`write_file`. It also states that child agents
cannot spawn their own subagents. The other 3 tools get similar
guidance-oriented descriptions.
Co-authored-by: Coder <coder@users.noreply.github.com>
## Summary
Fixes four frontend↔backend discrepancies in chat stream state
management that could cause duplicate content, UI flicker, and stale
stream state.
### Backend fixes (`coderd/chatd/chatd.go`)
**1. No-pubsub path double-replayed message_part events**
`Subscribe()` built an `initialSnapshot` containing `message_part`
events from `localSnapshot`, then the no-pubsub goroutine replayed the
same `localSnapshot` into the `mergedEvents` channel. Since `streamChat`
sends the snapshot first then reads the channel, the frontend received
every `message_part` twice. `applyMessagePartToStreamState` doesn't
deduplicate — text gets concatenated, so content appeared doubled.
Fix: Only forward live `localParts` in the no-pubsub goroutine; the
snapshot already contains the historical events.
**2. Snapshot missing status event**
The initial snapshot never included a `status` event. The frontend's
`shouldApplyMessagePart()` gates on status (`pending`/`waiting`), but
the initial status came from a separate REST query via `useEffect`.
During the race window between snapshot arrival and REST resolution,
`message_part` events could be incorrectly accepted or rejected.
Fix: Prepend a `status` event to the snapshot after loading the chat
from DB, so the frontend has the authoritative status from the very
first batch.
### Frontend fixes (`ChatContext.ts`)
**3. Scheduled stream reset not canceled by subsequent message_parts**
When a `message` event arrived, `scheduleStreamReset()` queued
`clearStreamState` via `requestAnimationFrame`. If new `message_part`
events arrived in the next WebSocket frame before the rAF fired, they
were pushed to `pendingMessageParts` without canceling the scheduled
reset. The rAF would fire between frames, clearing stream state, then
the next flush would re-populate it — causing a visible flash.
Fix: Call `cancelScheduledStreamReset()` when accumulating
`message_part` events.
**4. startTransition race with synchronous clearStreamState**
`flushMessageParts` wrapped `applyMessageParts` in `startTransition`,
which React can defer. If a `status: "waiting"` event arrived in the
same batch after `message_part` events, the status handler cleared
stream state synchronously, but the deferred `applyMessageParts`
callback could fire afterward and re-populate it.
Fix: Re-check `shouldApplyMessagePart()` inside the `startTransition`
callback at execution time.
### Tests added
- **Go**: `TestSubscribeSnapshotIncludesStatusEvent` — asserts the first
snapshot event is a status event
- **Go**: `TestSubscribeNoPubsubNoDuplicateMessageParts` — asserts the
events channel doesn't replay snapshot events
- **TS**: `cancels scheduled stream reset when message_part arrives
after message` — verifies stream state survives a [message,
message_part] batch
- **TS**: `does not apply message parts after status changes to waiting`
— verifies deferred applyMessageParts respects status transitions
## Summary
Adds a new agent-side process management HTTP API and rewrites the chat
execute tool to use it instead of SSH sessions.
## What changed
### New agent/agentproc/ package
- **headtail.go** — Thread-safe io.Writer with bounded memory (16KB head
+ 16KB tail ring buffer). Provides LLM-ready output with truncation
metadata and long-line truncation at 2048 bytes.
- **headtail_test.go** — 16 tests including race detector coverage for
concurrent writes.
- **process.go** — Manager + Process types for lifecycle management
using agentexec.Execer for proper OOM/nice scores.
- **api.go** — HTTP API following the agentfiles chi router pattern. 4
endpoints: start, list, output, signal.
### Agent wiring (agent/agent.go, agent/api.go)
Mounts the process API at /api/v0/processes, mirroring how agentfiles is
mounted.
### SDK (codersdk/workspacesdk/agentconn.go)
4 new AgentConn interface methods + 7 request/response types:
- StartProcess, ListProcesses, ProcessOutput, SignalProcess
### Execute tool rewrite (coderd/chatd/chattool/execute.go)
- SSH to Agent API: conn.StartProcess() + conn.ProcessOutput() polling
- New parameters: workdir, run_in_background
- Structured response: success, exit_code, wall_duration_ms, error,
truncated, note, background_process_id
- Non-interactive env vars: GIT_EDITOR=true, TERM=dumb, NO_COLOR=1,
PAGER=cat, etc.
- Output truncation: HeadTailBuffer caps at 32KB for LLM consumption
- File-dump detection with advisory notes suggesting read_file
- Default timeout: 60s to 10s
- Foreground polling: 200ms intervals until exit or timeout
## Architecture
State lives on the agent, surviving coderd failover and instance
changes. Any coderd replica can query any agent via HTTP over tailnet.
Adds a nullable `last_error` column to the `chats` table so error
reasons survive page reloads.
**Backend:**
- Migration adds `last_error TEXT` (nullable) to chats
- `UpdateChatStatus` writes the error reason when status transitions to
`error`, clears it (NULL) on recovery
- `convertChat` maps `sql.NullString` to `*string` in the SDK
**Frontend:**
- Sidebar falls back to `chat.last_error` when no stream error reason is
cached
- Chat detail page does the same for `persistedErrorReason`
- Fixtures updated for new required field
Kyle Carberry