Exposes the experimental Coder Agents chats API through the MCP tool
registry, so MCP clients (the hosted `/api/experimental/mcp/http` server
and `coder exp mcp server`) can start and drive server-side coding
agents.
New tools in `codersdk/toolsdk`, all thin wrappers over existing
`codersdk.ExperimentalClient` methods:
| Tool | Wraps |
|---|---|
| `coder_create_chat` | `CreateChat` (prompt, optional org, model
config, labels) |
| `coder_get_chat` | `GetChat` (status, last error, last turn summary,
workspace, files) |
| `coder_get_chat_messages` | `GetChatMessages` (user-facing parts,
chronological, cursor pagination, queued prompts) |
| `coder_send_chat_message` | `CreateChatMessage` (queue or interrupt
busy behavior) |
| `coder_interrupt_chat` | `InterruptChat` |
| `coder_archive_chat` | `UpdateChat` with `archived: true` |
| `coder_list_chat_model_configs` | `ListChatModelConfigs` (enabled
configs with default flag) |
Both MCP servers register tools from `toolsdk.All`, so no additional
wiring is needed. Responses are trimmed to what an MCP caller needs (IDs
as strings, user-facing transcripts) rather than full SDK payloads. No
new endpoints and no database changes.
Also adds MCP
[prompts](https://modelcontextprotocol.io/specification/2026-07-28/server/prompts)
for the chat workflows, defined once in `codersdk/toolsdk` and
registered by both servers:
| Prompt | Purpose |
|---|---|
| `coder_agents_delegate` | delegate a task to a Coder Agents chat and
monitor it to completion |
| `coder_agents_check` | check the status and recent activity of an
existing chat |
Each prompt declares the tools its workflow needs; the stdio server
skips prompts whose tools are excluded by `--allowed-tools`.
Tests run the tools against a chat-enabled coderdtest instance (fake
OpenAI-compatible provider plus in-process AI bridge), covering the full
lifecycle, an interrupt against a blocked turn, pagination cursors,
permission-dependent model config filtering, and argument validation.
Prompt coverage spans SDK rendering, the hosted
`prompts/list`/`prompts/get` round trip, and the stdio server including
allowlist gating.
> Mux created this PR on Mike's behalf.
## Problem
Coderd can expose an MCP server at `/api/experimental/mcp/http` (we have
this enabled on dogfood). Its workspace tools dialed agents through a
per-call client-side tailnet stack. Every tool call re-created a
WireGuard device, netstack, magicsock + UDP sockets, DERP connection,
coordinator websocket, and their goroutines — in a process that already
runs a long-lived shared tailnet. The duplicate stacks drove up resource
usage under load.
## Fix
Route this server's tool calls through the existing shared tailnet, so
none of those transports are reconstructed per call. Closing an
`AgentConn` now releases a tunnel reference instead of tearing down a
transport.
## Potential follow-up
`coder exp mcp server` still builds a fresh tailnet per call. It pays
per-call latency and causes coordinator/DERP churn. A shared CLI tailnet
is more involved — unlike coderd, the CLI has no existing shared tailnet
to reuse, so it would need a new long-lived client-side tailnet with
reconnect, sleep/wake, and idle-destination handling. There's less
motivation to optimize this, given the client-side MCP does not compete
for resources with coderd.
Closes CODAGT-199
> Generated by mux, but reviewed by a human
Fixes all our Go file imports to match the preferred spec that we've _mostly_ been using. For example:
```
import (
"context"
"time"
"github.com/prometheus/client_golang/prometheus"
"golang.org/x/xerrors"
"gopkg.in/natefinch/lumberjack.v2"
"cdr.dev/slog/v3"
"github.com/coder/coder/v2/codersdk/agentsdk"
"github.com/coder/serpent"
)
```
3 groups: standard library, 3rd partly libs, Coder libs.
This PR makes the change across the codebase. The PR in the stack above modifies our formatting to maintain this state of affairs, and is a separate PR so it's possible to review that one in detail.
Upgrades to slog v3 which includes a small, but backward incompatible API change to the acceptible call arguments when logging. This change allows us to verify via compile time type checking that arguments are correct and won't cause a panic, as was possible in slog v1, which this replaces (v2 was tagged but never used in coder/coder).
It also updates dependencies that also use slog and were updated.
I've left the `aibridge` dependency as a commit SHA, under the assumption that the team there (cc @pawbana @dannykopping ) will tag and update the dependency soon and on their own schedule.
Other dependencies, I pushed new tags.
# Add MCP HTTP server with streamable transport support
- Add MCP HTTP server with streamable transport support
- Integrate with existing toolsdk for Coder workspace operations
- Add comprehensive E2E tests with OAuth2 bearer token support
- Register MCP endpoint at /api/experimental/mcp/http with authentication
- Support RFC 6750 Bearer token authentication for MCP clients
Change-Id: Ib9024569ae452729908797c42155006aa04330af
Signed-off-by: Thomas Kosiewski <tk@coder.com>
Michael Suchacz