Fixes https://github.com/coder/internal/issues/1461
Two synchronization issues caused
`TestPortableDesktop_IdleTimeout_StopsRecordings` (and the
`MultipleRecordings` variant) to flake on macOS CI:
1. **`clk.Advance(idleTimeout)` was not awaited.** In
`MultipleRecordings`, both idle timers fire simultaneously but their
`fire()` goroutines race to remove themselves from the mock clock's
event list. Without `MustWait`, the second timer may still be in `m.all`
when the next `Advance` is called, causing `"cannot advance ... beyond
next timer/ticker event in 0s"`.
2. **The test depended on SIGINT being handled promptly.** After the
`stop_timeout` timer was released, the test relied entirely on the shell
process handling SIGINT (via `rec.done`). On macOS, `/bin/sh` may not
interrupt `wait` reliably, leaving `lockedStopRecordingProcess` blocked
in its `select` while holding `p.mu` — deadlocking the
`require.Eventually` callback.
### Fix
Wait for each `Advance` to complete and advance past the 15s stop
timeout so the process is forcibly killed via the timer path,
independent of signal handling.
Verified with 1000 iterations (500 per test) with zero failures.
> Generated with [Coder Agents](https://coder.com/agents)
The agents chat interface displays thumbnails for videos recorded by the
computer use agent. Currently, to display a thumbnail, the frontend
downloads the entire video and shows the first frame. This PR starts
storing a new thumbnail file in the database for every recorded video,
and exposes the file id in the `wait_agent` tool result alongside the
recording file id, so the frontend can fetch just the thumbnail.
## Problem
MCP servers configured in `.mcp.json` with stdio transport are
discovered successfully (tools appear) but die immediately after
connection, making all tool calls fail.
## Root Cause
In `connectServer`, the subprocess is spawned with `connectCtx` — a
30-second timeout context whose `cancel()` is deferred:
```go
connectCtx, cancel := context.WithTimeout(ctx, connectTimeout)
defer cancel()
if err := c.Start(connectCtx); err != nil { ... }
```
The mcp-go stdio transport calls `exec.CommandContext(connectCtx, ...)`.
When `connectServer` returns, `cancel()` fires, and
`exec.CommandContext` sends SIGKILL to the subprocess. The process
immediately becomes a zombie.
Confirmed by checking `/proc/<pid>/status` after context cancellation:
```
State: Z (zombie)
```
## Fix
Pass the parent `ctx` (which is `a.gracefulCtx` — the agent's long-lived
context) to `c.Start()`. `connectCtx` continues to bound only the
`Initialize()` handshake. The subprocess is cleaned up when the Manager
is closed or the parent context is canceled.
## Regression Test
Added `TestConnectServer_StdioProcessSurvivesConnect` which:
- Spawns a real subprocess (re-execs the test binary as a fake MCP
server)
- Calls `connectServer` and lets it return (internal `connectCtx` gets
canceled)
- Verifies the subprocess is still alive by calling `ListTools`
The test **fails** on the old code with `transport error: context
deadline exceeded` and **passes** with the fix.
> Generated with [Coder Agents](https://coder.com/agents)
This PR introduces screen recording of the computer use agent using the
virtual desktop.
- Screen recording is triggered by a `wait_agent` tool call. Recording
is stopped by a successful `wait_agent` tool call or when there hasn't
been any desktop activity for 10 minutes.
- Recordings are handled by the `portabledesktop` cli via the `record`
command. The videos are sped up in periods of inactivity.
- Recordings are saved to the database to the `chat_files` table.
There's a hard limit of 100MB per recording. Larger recordings are
dropped.
- A successful `wait_agent` on a computer use subagent tool call returns
a `recording_file_id`, later allowing the frontend to display the
corresponding video.
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>
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.
- Move `agent/agentdesktop/` to `agent/x/agentdesktop/` to signal
experimental/unstable status
- Update import paths in `agent/agent.go` and `api_test.go`
> 🤖 This mechanical refactor was performed by an agent. I made sure it
didn't change anything it wasn't supposed to.
Kyle Carberry