> This PR was authored by Mux on behalf of Mike.
Chats sharing one workspace (e.g. sibling subagents) all wrote to
`/home/coder/PLAN.md`, causing plan file collisions. This change derives
a unique plan path per chat from the workspace home directory and chat
ID.
## Changes
* `write_file`, `edit_files`, and `propose_plan` reject any `plan.md`
variant (case-insensitive) at the workspace home root, with a clear
error pointing to the chat-specific path.
* Root chats receive a `<plan-file-path>` block inlined in the main
system prompt with the concrete path.
* Prompt and tool descriptions no longer hardcode `/home/coder/PLAN.md`.
* Plan path handling is POSIX-only (forward-slash), relying on the
contract that workspace agent paths are normalized before reaching
chatd.
* Updated `ProposePlanTool.stories.tsx` to use per-chat path examples.
* Full test coverage for plan path detection, legacy-path rejection in
all three tools, inline prompt rendering, and fallback behavior.
Fixes https://github.com/coder/internal/issues/1436
* Adds organization_id to chats with backfill (workspace org → user org membership → default org)
* No support yet for ACLs (follow-up issue)
- Cross-org workspace binding rejected (both in `CreateChatRequest` and in `create_workspace` tool
- Adds `OrganizationAutocomplete` to `AgentCreateForm`
- Docs updated with `organization_id` in chats-api.md
> 🤖 Written by a Coder Agent. Reviewed by many humans and many agents.
---------
Co-authored-by: Mathias Fredriksson <mafredri@gmail.com>
Adds client-executed dynamic tools to the chat API. Dynamic tools are
declared by the client at chat creation time, presented to the LLM
alongside built-in tools, but executed by the client rather than chatd.
This enables external systems (Slack bots, IDE extensions, Discord bots,
CI/CD integrations) to plug custom tools into the LLM chat loop without
modifying chatd's built-in tool set.
Modeled after OpenAI's Assistants API: the chat pauses with
`requires_action` status when the LLM calls a dynamic tool, the client
POSTs results back via `POST /chats/{id}/tool-results`, and the chat
resumes.
See [this example](https://github.com/coder/coder-slackbot-poc) as a
reference for how this is used. It's highly-configurable, which would
enable creating chats from webhooks, periodically polling, or running as
a Slackbot.
<details>
<summary>Design context</summary>
### Architecture
The chatloop **exits** when it encounters dynamic tools and
**re-enters** when results arrive. No blocking channels, no pubsub for
tool results, no in-memory registry. The DB is the only coordination
mechanism.
```
Phase 1 (chatloop):
LLM response → execute built-in tools only →
Persist(assistant + built-in results) →
status = requires_action → chatloop exits
Phase 2 (POST /tool-results):
Persist(dynamic tool results) →
status = pending → wakeCh → chatloop re-enters
```
### Validation (POST /tool-results)
1. Chat status must be `requires_action` (409 if not)
2. Read chat's `dynamic_tools` → set of dynamic tool names
3. Read last assistant message → extract tool-call parts matching
dynamic tool names
4. Submitted tool_call_ids must match exactly (400 for missing/extra)
5. Persist tool-result message parts, set status to `pending`, signal
wake
### Idempotency
Tool call IDs scoped per LLM step. State machine (`requires_action` →
`pending`) is the guard. First POST wins, subsequent get 409.
### Mixed tool calls
When the LLM calls both built-in and dynamic tools in one step, built-in
tools execute immediately. Their results are persisted in phase 1.
Dynamic tool results arrive via POST in phase 2. The LLM sees all
results when the chatloop resumes.
</details>
> 🤖 Generated by Coder Agents
## Summary
Replaces N per-chat heartbeat goroutines with a single centralized
heartbeat loop that issues one `UPDATE` per 30s interval for all running
chats on a worker.
## Problem
Each running chat spawned a dedicated goroutine that issued an
individual `UPDATE chats SET heartbeat_at = NOW() WHERE id = $1 AND
worker_id = $2 AND status = 'running'` query every 30 seconds. At 10,000
concurrent chats this produces **~333 DB queries/second** just for
heartbeats, plus ~333 `ActivityBumpWorkspace` CTE queries/second from
`trackWorkspaceUsage`.
## Solution
New `UpdateChatHeartbeats` (plural) SQL query replaces the old singular
`UpdateChatHeartbeat`:
```sql
UPDATE chats
SET heartbeat_at = @now::timestamptz
WHERE worker_id = @worker_id::uuid
AND status = 'running'::chat_status
RETURNING id;
```
A single `heartbeatLoop` goroutine on the `Server`:
1. Ticks every `chatHeartbeatInterval` (30s)
2. Issues one batch UPDATE for all registered chats
3. Detects stolen/completed chats via set-difference (equivalent of old
`rows == 0`)
4. Calls `trackWorkspaceUsage` for surviving chats
`processChat` registers an entry in the heartbeat registry instead of
spawning a goroutine.
## Impact
| Metric | Before (10K chats) | After (10K chats) |
|---|---|---|
| Heartbeat queries/sec | ~333 | ~0.03 (1 per 30s per replica) |
| Heartbeat goroutines | 10,000 | 1 |
| Self-interrupt detection | Per-chat `rows==0` | Batch set-difference |
---
> 🤖 Generated by Coder Agents
<details><summary>Implementation notes</summary>
- Uses `@now` parameter instead of `NOW()` so tests with `quartz.Mock`
can control timestamps.
- `heartbeatEntry` stores `context.CancelCauseFunc` + workspace state
for the centralized loop.
- `recoverStaleChats` is unaffected — it reads `heartbeat_at` which is
still updated.
- The old singular `UpdateChatHeartbeat` is removed entirely.
- `dbauthz` wrapper uses system-level `rbac.ResourceChat` authorization
(same pattern as `AcquireChats`).
</details>
Piggybacks on #23878. Moves instruction file reading and skill discovery
from `chatd` (server-side, via multiple `LS`/`ReadFile` round-trips
through the agent connection) to the agent itself (local filesystem
access).
This intentionally drops backward compatibility with older agents that
don't support the context-config endpoint. Agents and server are
deployed together; there is no rolling-update contract to maintain here.
## What changed
The agent's `GET /api/v0/context-config` response now returns
`[]ChatMessagePart` directly — the same types chatd persists. This
eliminates intermediate type conversions and makes the protocol
extensible.
| Field | Type | Description |
|---|---|---|
| `parts` | `[]ChatMessagePart` | Context-file and skill parts, ready to
persist |
| `working_dir` | `string` | Agent's resolved working directory |
Removed from the response: `instructions_dirs`, `instructions_file`,
`skills_dirs`, `skill_meta_file`, `mcp_config_files` — the agent reads
files locally and returns their content as parts.
Removed from chatd: all legacy `LS`/`ReadFile` fallback code
(`readHomeInstructionFile`, `readInstructionDirFile`, `DiscoverSkills`
via LS, etc).
## Why
The previous architecture had the agent resolve paths, serve them over
HTTP, then `chatd` make N+1 round-trips back through the agent
connection to read files. The agent has direct filesystem access and
should just read the files.
## Key design decisions
- **Agent returns `ChatMessagePart` directly** — same types chatd
persists. No intermediate `InstructionFileEntry`/`SkillEntry` types
needed.
- **`SkillMeta.MetaFile`** — persisted via `ContextFileSkillMetaFile` on
the skill part, so custom meta file names
(`CODER_AGENT_EXP_SKILL_META_FILE`) survive across chat turns.
- **No pre-read body** — `read_skill` always dials the workspace to
fetch the skill body on demand. Simpler than caching the body in the
response.
- **MCP config paths kept agent-internal** — `MCPConfigFiles()` getter,
not sent over the wire.
- **No backward compat fallback** — old agents that don't support
context-config get no instruction files. This is acceptable since agent
and server deploy together.
- Extend `TestChatTemplateAllowlistEnforcement` to also exercise
`read_template` and `create_workspace` through the allowlist
- Mock LLM now chains 4 tool calls: list_templates, read_template
(blocked), read_template (allowed), create_workspace (blocked)
- Wire dummy `CreateWorkspace` config into test server so the tool
reaches the allowlist check
- Generalize tool result collection to support multiple calls per tool
name
> 🤖 Created by Coder Agents and reviewed by Kyle the human.
- Change `errChatHasNoWorkspaceAgent` message from cryptic `"chat has no
workspace agent"` to actionable `"workspace has no running agent: the
workspace may be stopped. Use the start_workspace tool to start it, or
create_workspace to create a new one"`
- Update test assertions to match the new message substring
> 🤖 Written by a Coder Agent. Reviewed by a human.
Previously, `CreateChat` inserted the `chats` row with the DB default
status (`waiting`), then updated it to `pending` in the same transaction
via `setChatPendingWithStore`. This wasted two extra queries per chat
creation (`GetChatByID` + `UpdateChatStatus`) and rewrote the same row
immediately after inserting it.
Now `CreateChat` passes the status directly to `InsertChat`, so the row
is written once in its final create-time state. The
`setChatPendingWithStore` helper is removed entirely. `InsertChat` now
requires an explicit `status` parameter at all callsites instead of
relying on a DB column default.
## Motivation
On an experimental branch we're trialing firing all chatd notifications
from plpgsql triggers. The old two-step insert made that awkward: in an
`AFTER INSERT` trigger, `NEW` only contained the insert-time row
(`waiting`), not the final committed state (`pending`). To emit the
correct event payload the trigger had to be deferred and re-read the row
from `chats` at commit time.
With this change, `NEW` already contains the correct row to publish — no
deferred trigger, no extra `SELECT`, simpler and cheaper trigger logic.
That said, this seems like a worthwhile change regardless of the trigger
experiment: writing the final row state once removes unnecessary DB work
on every chat creation and makes the create path easier to reason about.
Replace hardcoded paths for instruction files, skills, and MCP config
with
values read from `CODER_AGENT_EXP_*` environment variables. Template
authors
configure paths via the existing `coder_agent` `env` block. The agent
resolves `~`, relative, and absolute paths locally, then serves the
resolved config over `GET /api/v0/context-config`. `chatd` fetches this
once per workspace attach and falls back to today's defaults for older
agents.
All path env vars are comma-separated, allowing multiple directories:
| Env Var | Default | Controls |
|---|---|---|
| `CODER_AGENT_EXP_INSTRUCTIONS_DIRS` | `~/.coder` | Dirs containing the
instruction file |
| `CODER_AGENT_EXP_INSTRUCTIONS_FILE` | `AGENTS.md` | Instruction file
name |
| `CODER_AGENT_EXP_SKILLS_DIRS` | `.agents/skills` | Skills directories
|
| `CODER_AGENT_EXP_SKILL_META_FILE` | `SKILL.md` | Skill metadata file
name |
| `CODER_AGENT_EXP_MCP_CONFIG_FILES` | `.mcp.json` | MCP config files |
### Example
```hcl
resource "coder_agent" "main" {
os = "linux"
arch = "amd64"
env = {
CODER_AGENT_EXP_INSTRUCTIONS_DIRS = "/opt/company/agent-config,~/.coder"
CODER_AGENT_EXP_INSTRUCTIONS_FILE = "CLAUDE.md"
CODER_AGENT_EXP_SKILLS_DIRS = "/opt/company/ai-skills,.agents/skills"
CODER_AGENT_EXP_MCP_CONFIG_FILES = "/opt/company/mcp.json,.mcp.json"
}
}
```
<details>
<summary>Implementation Details</summary>
### Architecture
Follows the same pattern as MCP tool discovery:
agent resolves locally → exposes via HTTP → chatd consumes.
**Agent-side** (`agent/agentcontextconfig/`):
- `ResolvePath` / `ResolvePaths` handle `~`, relative, and absolute path
forms; returns `""` for relative paths when baseDir is empty
- `Config` reads env vars, falls back to defaults, resolves all paths
- `GET /api/v0/context-config` serves the resolved config as JSON
**chatd-side** (`coderd/x/chatd/`):
- Calls `conn.ContextConfig()` once on first workspace attach
- Falls back to hardcoded defaults on 404 (older agents)
- Iterates instruction dirs, skills dirs using resolved absolute paths
- `LSRelativityRoot` everywhere — no more home/root juggling
### Key design decisions
- **`EXP_` prefix**: env vars use `CODER_AGENT_EXP_*` to indicate
experimental status
- **Plural names**: comma-separated vars use plural names (`DIRS`,
`FILES`); single-value vars use singular (`FILE`)
- **Defaults in `workspacesdk`**: default constants live in
`codersdk/workspacesdk/` so both agent and server reference them without
cross-layer imports
- **`skillMetaFile` persistence**: stored on context-file parts via
`ContextFileSkillMetaFile` and restored on subsequent chat turns so
custom values survive across turns
- **Working dir dedup**: `slices.Contains` guard prevents reading the
same instruction file from both `InstructionsDirs` and the working
directory
- **MCP server dedup**: first-occurrence-wins dedup prevents leaking
duplicate connections from overlapping config files
- **ResolvePath safety**: returns `""` for relative paths when `baseDir`
is empty, so `ResolvePaths` filters them out
### Files changed
| File | Change |
|---|---|
| `agent/agentcontextconfig/` | New package — path resolution + HTTP
endpoint |
| `codersdk/workspacesdk/agentconn.go` | `ContextConfigResponse` type,
default constants, client method |
| `agent/agent.go` + `agent/api.go` | Wire up endpoint, pass config to
MCP |
| `agent/x/agentmcp/manager.go` | Accept `[]string` MCP config paths,
dedup by name |
| `coderd/x/chatd/chatd.go` | Fetch config, thread through, named
returns |
| `coderd/x/chatd/instruction.go` | Accept configurable dir + file name,
`skillMetaFileFromParts` |
| `coderd/x/chatd/chattool/skill.go` | Accept configurable dirs + meta
file |
| `codersdk/chats.go` | `ContextFileSkillMetaFile` field for persistence
|
### Test coverage
- `TestConfig` (4 cases): defaults, custom env vars, whitespace
trimming, comma-separated dirs
- `TestResolvePath` / `TestResolvePaths`: including empty baseDir edge
case
- `TestPersistInstructionFilesFallbackOnOlderAgent`: backward-compat
path when `ContextConfig` returns 404
- `TestChatMessagePartVariantTags`: updated exclusion list for new
internal field
### Backward compatibility
Older agents return 404 for the new endpoint. `chatd` catches this and
falls back to today's defaults via `readHomeInstructionFile` (using
`LSRelativityHome`). Existing workspaces work with no changes.
</details>
Archiving a chat now transitions pending or running chats to waiting
before setting the archived flag. This publishes a status notification
on `ChatStreamNotifyChannel` so `subscribeChatControl` cancels the
active `processChat` context via `ErrInterrupted` — the same codepath
used by the stop button.
The `processChat` cleanup also skips queued-message auto-promotion when
the chat is archived, so archiving behaves like a hard stop rather than
interrupt-and-continue.
Relates to https://github.com/coder/coder/issues/23666
## Summary
Fixes three flaky chatd tests that intermittently fail due to timing
races with the background run loop.
Closescoder/internal#1428
## Root Cause
`CreateChat` and `PromoteQueued` call `signalWake()` which writes to
`wakeCh`, triggering `processOnce` immediately. Even though
`newTestServer` sets `PendingChatAcquireInterval: testutil.WaitLong` to
prevent ticker-based polling, the wake channel bypasses this. This
causes `processOnce` to acquire and process the chat concurrently with
the test's manual DB updates and assertions.
### Failing tests
| Test | Failure | Cause |
|------|---------|-------|
| `TestPromoteQueuedAllowsAlreadyQueuedMessageWhenUsageLimitReached` |
`expected: "pending", actual: "running"` | Wake from `CreateChat` races
with manual `UpdateChatStatus`; wake from `PromoteQueued` acquires the
chat before the status assertion |
| `TestSendMessageInterruptBehaviorQueuesAndInterruptsWhenBusy` |
`should have 1 item(s), but has 2` | Wake from `CreateChat` triggers
`processChat` which auto-promotes a queued message, adding an extra row
to `chat_messages` |
| `TestSubscribeNoPubsubNoDuplicateMessageParts` | `Condition satisfied`
(duplicate events) | Pre-existing `WaitGroup.Add/Wait` race in the
`Eventually` + `WaitUntilIdleForTest` pattern |
## Fix
Introduces a `waitForChatProcessed` helper that:
1. Polls until the chat reaches a **terminal state** (not pending AND
not running)
2. Then calls `WaitUntilIdleForTest` to wait for the inflight
`WaitGroup`
Waiting for a terminal state (not just "not pending") avoids a
`sync.WaitGroup` `Add/Wait` race: `AcquireChats` updates the DB status
to `running` **before** `processOnce` calls `inflight.Add(1)`. Checking
only `status != pending` could return while `Add(1)` hasn't happened
yet, causing `Wait()` to return prematurely.
### Per-test changes
- **`TestSendMessageInterruptBehaviorQueuesAndInterruptsWhenBusy`**:
Call `waitForChatProcessed` after `CreateChat` before manually setting
running status
-
**`TestPromoteQueuedAllowsAlreadyQueuedMessageWhenUsageLimitReached`**:
Call `waitForChatProcessed` after `CreateChat`; remove the inherently
racy `status == pending` assertion after `PromoteQueued` (the wake
immediately acquires the chat). Key assertions on promoted message,
queue state, and message count remain.
- **`TestSubscribeNoPubsubNoDuplicateMessageParts`**: Replace inline
`Eventually` with the safer `waitForChatProcessed` helper
## Verification
All three tests pass 150 consecutive executions with `-race -count=10`
across 15 runs (0 failures).
Previously, when a user sent a message, there was a 0–1000ms (avg
~500ms) polling delay before processing began.
`SendMessage`/`CreateChat`/`EditMessage` set `status='pending'` in the
DB and returned, but nothing woke the processing loop — it was a blind
1-second ticker.
## Changes
**Event-driven acquisition (main change):** Adds a `wakeCh` channel to
the chatd `Server`. `CreateChat`, `SendMessage`, `EditMessage`, and
`PromoteQueued` call `signalWake()` after committing their transactions,
which wakes the run loop to call `processOnce` immediately. The 1-second
ticker remains as a fallback safety net for edge cases (stale recovery,
missed signals).
**Buffer WebSocket write channel:** Changes the
`OneWayWebSocketEventSender` event channel from unbuffered to buffered
(64), decoupling the event producer from WebSocket write speed. The
existing 10s write timeout guards against stuck connections.
<details><summary>Implementation plan & analysis</summary>
The full latency analysis identified these sources of delay in the
streaming pipeline:
1. **Chat acquisition polling** — 0–1000ms (avg 500ms) dead time per
message. Fixed by wake channel.
2. **Unbuffered WebSocket write channel** — each token blocked on the
previous WS write completing. Fixed by buffering.
3. **PersistStep DB transaction per step** — `FOR UPDATE` lock + batch
insert. Not addressed in this PR (medium risk, would overlap DB write
with next provider TTFB).
4. **Multi-hop channel pipeline** — 4 channel hops per token. Not
addressed (medium complexity).
</details>
<details><summary>Test stabilization notes</summary>
`signalWake()` causes the chatd daemon to process chats immediately
after creation/send/edit, which exposed timing assumptions in several
tests that expected chats to remain in `pending` status long enough to
assert on. These tests were updated with `require.Eventually` +
`WaitUntilIdleForTest` patterns to wait for processing to settle before
asserting.
The race detector (`test-go-race-pg`) shows failures in
`TestCreateWorkspaceTool_EndToEnd` and `TestAwaitSubagentCompletion` —
these appear to be pre-existing races in the end-to-end chat flow that
are now exercised more aggressively because processing starts
immediately instead of after a 1s delay. Main branch CI (race detector)
passes without these changes.
</details>
## Summary
Adds read/unread tracking for chats so users can see which agent
conversations have new assistant messages they haven't viewed.
## Backend Changes
- Adds `last_read_message_id` column to the `chats` table (migration
000439).
- Computes `has_unread` as a virtual column in `GetChatsByOwnerID` using
an `EXISTS` subquery checking for assistant messages beyond the read
cursor.
- Exposes `has_unread` on the `codersdk.Chat` struct and auto-generated
TypeScript types.
- Updates `last_read_message_id` on stream connect/disconnect in
`streamChat`, avoiding per-message API calls during active streaming.
- Uses `context.WithoutCancel` for the deferred disconnect write so the
DB update succeeds even after the client disconnects.
## Frontend Changes
- Bold title (`font-semibold`) for unread chats in the sidebar.
- Small blue dot indicator next to the relative timestamp.
- Suppresses unread indicator for the currently active chat via
`isActive` from NavLink.
## Design Decisions
- Only `assistant` messages count as unread — the user's own messages
don't trigger the indicator.
- No foreign key on `last_read_message_id` since messages can be deleted
(via rollback/truncation) and the column is just a high-water mark.
- Zero API calls during streaming: exactly 2 DB writes per stream
session (connect + disconnect).
- Unread state refreshes on chat list load and window focus. The
`watchChats` WebSocket optimistically marks non-active chats as unread
on `status_change` events, but does not carry a server-computed
`has_unread` field. Navigating to a chat optimistically clears its
unread indicator in the cache.
Fixes expired MCP OAuth2 tokens causing 401 errors and stale
`auth_connected` status in the UI.
When users authenticate MCP servers (e.g. GitHub) via OAuth2, the access
token and refresh token are stored in the database. However, when the
access token expired, nothing refreshed it anywhere:
- **chatd**: sent the expired token as-is, getting a 401 and skipping
the MCP server
- **list/get endpoints**: reported `auth_connected: true` just because a
token record existed, regardless of expiry
## Changes
### Shared utility: `mcpclient.RefreshOAuth2Token`
Pure function that uses `golang.org/x/oauth2` `TokenSource` to check if
a token is expired (or within 10s of expiry) and refresh it. No DB
dependency — callers handle persistence.
### chatd (`coderd/x/chatd/chatd.go`)
Before calling `mcpclient.ConnectAll`, refreshes expired tokens.
Persists new credentials to the database. Falls back to the old token if
refresh fails.
### List/get MCP server endpoints (`coderd/mcp.go`)
Both `listMCPServerConfigs` and `getMCPServerConfig` now attempt refresh
when checking `auth_connected`. If the token is expired:
- **Has refresh token**: attempt refresh, persist result, report
`auth_connected` based on success
- **No refresh token**: report `auth_connected: false` if expired
This means the UI accurately reflects whether the user's token is
actually usable, rather than just whether a record exists.
<details>
<summary>Design notes</summary>
- `RefreshOAuth2Token` lives in `mcpclient` to avoid circular imports
(`coderd` → `chatd` → `mcpclient` is fine; `chatd` → `coderd` would be
circular).
- DB persistence is handled by each caller with their own authz context
(`AsSystemRestricted` in both cases).
- The `buildAuthHeaders` warning in mcpclient about expired tokens is
kept as defense-in-depth logging.
</details>
## Problem
Chats with a persisted `agent_id` binding hang indefinitely when the
workspace is stopped. The stale agent row still exists in the DB, so
`ensureWorkspaceAgent` succeeds, but the dial blocks forever in
`AwaitReachable`. The MCP discovery goroutine used an unbounded context,
so `g2.Wait()` never returned and the LLM never started.
## Fix
Three targeted changes restore the pre-binding behavior where stopped
workspaces degrade gracefully instead of blocking:
1. **`dialWithLazyValidation`**: "no agents in latest build" is now a
terminal fast-fail — the hanging dial is canceled and
`errChatHasNoWorkspaceAgent` returned immediately, instead of falling
through to `waitForOriginalDial`.
2. **Pre-LLM workspace setup**: MCP discovery and instruction
persistence gate on `workspaceAgentIDForConn` before attempting any
dial. MCP discovery is bounded by a 5s timeout and checks the in-memory
tool cache first (using the cheap cached agent from
`ensureWorkspaceAgent`), so the common subsequent-turn path has zero DB
queries.
3. **`persistInstructionFiles`**: tracks whether the workspace
connection succeeded and skips sentinel persistence on failure, so the
next turn retries if the workspace is restarted.
## Scenarios
**Running workspace, subsequent turn (hot path):** MCP cache hit via
in-memory cached agent. Zero DB queries, zero dials. Unchanged from
#23274.
**Stopped workspace, persisted binding (the bug):** MCP cache hit (stale
descriptors, fine — they fail at invocation). Pre-LLM setup completes
instantly. Tool invocation enters `dialWithLazyValidation`, dial fails
or hangs, validation discovers no agents, returns
`errChatHasNoWorkspaceAgent`. Model sees the error and can call
`start_workspace`.
**New chat, running workspace:** `ensureWorkspaceAgent` resolves via
latest-build, persists binding. MCP discovery dials and caches tools.
**New chat, stopped workspace:** `ensureWorkspaceAgent` finds no agents,
returns `errChatHasNoWorkspaceAgent`. Pre-LLM setup skips. LLM starts
with built-in tools only.
**Rebuilt workspace (agent switched):** MCP cache hit with stale agent
(harmless for one turn). Tool invocation dials stale agent, fails fast,
`dialWithLazyValidation` switches to new agent, persists updated
binding.
**Workspace restarted after stop:** No sentinel was persisted during the
stopped turn, so instruction persistence retries. Agent binding switches
to the new agent via `workspaceAgentIDForConn`.
**Transient DB error during validation:** Not
`errChatHasNoWorkspaceAgent`, so `dialWithLazyValidation` falls through
to `waitForOriginalDial` (cannot prove stale). No false positive.
**Tool invocation on stopped workspace:** `getWorkspaceConn` calls
`ensureWorkspaceAgent` (returns stale row), then
`dialWithLazyValidation` validation discovers no agents, returns
`errChatHasNoWorkspaceAgent`, cached state cleared, error returned to
model.
Coder's chat (chatd) can now discover and use MCP servers configured in
a workspace's `.mcp.json` file. This brings project-specific tooling
(GitHub, databases, docs servers, etc.) into the chat without any manual
configuration.
## How it works
The workspace agent reads `.mcp.json` from the workspace directory (same
format Claude Code uses), connects to the declared MCP servers —
spawning child processes for stdio servers and connecting over the
network for HTTP/SSE — and caches their tool lists. Two new agent HTTP
endpoints expose this:
- `GET /api/v0/mcp/tools` returns the cached tool list (supports
`?refresh=true`)
- `POST /api/v0/mcp/call-tool` proxies calls to the correct server
On each chat turn, chatd calls `ListMCPTools` through the existing
`AgentConn` tailnet connection, wraps each tool as a
`fantasy.AgentTool`, and adds them to the LLM's tool set alongside
built-in and admin-configured MCP tools. Tool names are prefixed with
the server name (`github__create_issue`) to avoid collisions.
Failed server connections are logged and skipped — they never block the
agent or break the chat. Child stdio processes are terminated on agent
shutdown.
## Summary
This change removes the steady-state "resolve the latest workspace
agent" query from chat execution.
Instead of asking the database for the latest build's agent on every
turn, a chat now persists the workspace/build/agent binding it actually
uses and reuses that binding across subsequent turns. The common path
becomes "load the bound agent by ID and dial it", with fallback paths to
repair the binding when it is missing, stale, or intentionally changed.
## What changes
- add `workspace_id`, `build_id`, and `agent_id` binding fields to
`chats`
- expose those fields through the chat API / SDK so the execution
context is explicit
- load the persisted binding first in chatd, instead of always resolving
the latest build's agent
- persist a refreshed binding when chatd has to re-resolve the workspace
agent
- keep child / subagent chats on the same bound workspace context by
inheriting the parent binding
- leave `build_id` / `agent_id` unset for flows like `create_workspace`,
then bind them lazily on the next agent-backed turn
## Runtime behavior
The binding is treated as an optimistic cache of the agent a chat should
use:
- if the bound agent still exists and dials successfully, we use it
without a latest-build lookup
- if the bound agent is missing or no longer reachable, chatd
re-resolves against the latest build and persists the new binding
- if a workspace mutation changes the chat's target workspace, the
binding is updated as part of that mutation
To avoid reintroducing a hot-path query, dialing uses lazy validation:
- start dialing the cached agent immediately
- only validate against the latest build if the dial is still pending
after a short delay
- if validation finds a different agent, cancel the stale dial, switch
to the current agent, and persist the repaired binding
## Result
The hot path stops issuing
`GetWorkspaceAgentsInLatestBuildByWorkspaceID` for every user message,
which is the source of the DB pressure this PR is addressing. At the
same time, chats still converge to the correct workspace agent when the
binding becomes stale due to rebuilds or explicit workspace changes.
Problem: previously, the deployment-wide chat template allowlist was never actually wired in from `chatd.go`
- Extracts `parseChatTemplateAllowlist` into shared `coderd/util/xjson.ParseUUIDList`
- Adds `Server.chatTemplateAllowlist()` method that reads the allowlist from DB
- Passes `AllowedTemplateIDs` callback to `ListTemplates`, `ReadTemplate`, and `CreateWorkspace` tool constructors
> 🤖 Created by Coder Agents and reviewed by a human.
Adds a `propose_plan` tool that presents a workspace markdown file as a
dedicated plan card in the agent UI.
The workflow is: the agent uses `write_file`/`edit_files` to build a
plan file (e.g. `/home/coder/PLAN.md`), then calls `propose_plan(path)`
to present it. The backend reads the file via `ReadFile` and the
frontend renders it as an expanded markdown preview card.
**Backend** (`coderd/x/chatd/chattool/proposeplan.go`): new tool
registered as root-chat-only. Validates `.md` suffix, requires an
absolute path, reads raw file content from the workspace agent. Includes
1 MiB size cap.
**Frontend** (`site/src/components/ai-elements/tool/`): dedicated
`ProposePlanTool` component with `ToolCollapsible` + `ScrollArea` +
`Response` markdown renderer, expanded by default. Custom icon
(`ClipboardListIcon`) and filename-based label.
**System prompt** (`coderd/x/chatd/prompt.go`): added `<planning>`
section guiding the agent to research → write plan file → iterate → call
`propose_plan`.
TestInterruptAutoPromotionIgnoresLaterUsageLimitIncrease still relied on
wall-clock polling after the acquire loop moved to a mock clock, so it
could assert before chatd finished its asynchronous cleanup and
auto-promotion work.
Wait on explicit request-start signals and on the server's in-flight
chat work before asserting the intermediate and final database state.
This keeps the test synchronized with the actual processor lifecycle
instead of scheduler timing.
Closes https://github.com/coder/internal/issues/1406
- 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