MCP servers may accept `initialize` unauthenticated but return `401`
with a `WWW-Authenticate` challenge only on a later request such as
`tools/list` or `tools/call`. Previously Zed only started the Auth flow
when `initialize` itself was challenged, so these servers failed
opaquely and stayed stuck in `Running` with a dead client.
`ContextServerStore` now handles `TransportError::AuthRequired` returned
from any request, not just startup: it runs Auth discovery and
transitions the server into `AuthRequired` so the UI offers to
authenticate. The discovery logic is shared with the startup path, and
the tool/prompt request sites route their errors through it.
Release Notes:
- Fixed MCP servers that require auth only on tool calls (not on
`initialize`) failing to prompt for authentication.
---------
Co-authored-by: Tom Houlé <tom@tomhoule.com>
Updates our MCP implementation to support `2025-06-18` and `2025-11-25`
Self-Review Checklist:
- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable
Closes#54458, #53456
Release Notes:
- Support latest MCP version (`2025-11-25`)
Closes#43162
Implements the OAuth 2.0 Authorization Code + PKCE authentication flow
for remote MCP servers using Streamable HTTP transport, as specified by
the [MCP auth
specification](https://modelcontextprotocol.io/specification/2025-03-26/basic/authorization).
Previously, connecting to a remote MCP server that required OAuth would
silently fail with a timeout — the server's 401 response was never
handled. Now, Zed detects the 401, performs OAuth discovery, and guides
the user through browser-based authentication.
Step-up authentication and pre-registered clients are not in scope for
this PR, but will be done as follow-ups.
## Overview
- **401 detection** — When the HTTP transport receives a 401 during
server startup, it surfaces a typed `TransportError::AuthRequired` with
parsed `WWW-Authenticate` header info.
- **OAuth discovery** — Protected Resource Metadata (RFC 9728) and
Authorization Server Metadata (RFC 8414) are fetched to locate the
authorization and token endpoints.
- **Client registration** — Zed first tries CIMD (Client ID Metadata
Document) hosted at `zed.dev`. If the server doesn't support CIMD, falls
back to Dynamic Client Registration (DCR).
- **Browser flow** — A loopback HTTP callback server starts on a
preferred fixed port (27523, listed in the CIMD), the user's browser
opens to the authorization URL, and Zed waits for the callback with the
authorization code.
- **Token exchange & persistence** — The code is exchanged for
access/refresh tokens using PKCE. The session is persisted in the system
keychain so subsequent startups restore it without another browser flow.
- **Automatic refresh** — The HTTP transport transparently refreshes
expired tokens using the refresh token, and persists the updated session
to the keychain.
## UI changes
- Servers requiring auth show a warning indicator with an
**"Authenticate"** button
- During auth, a spinner and **"Waiting for authorization..."** message
are shown
- A **"Log Out"** option is available in the server settings menu for
OAuth-authenticated servers
- The configure server modal handles the auth flow inline when
configuring a new server that needs authentication.
Release Notes:
- Added OAuth authentication support for remote MCP servers. Servers
requiring OAuth now show an "Authenticate" button when they need you to
log in. You will be redirected in your browser to the authorization
server of the MCP server to go through the authorization flow.
---------
Co-authored-by: Danilo Leal <daniloleal09@gmail.com>
### Closes
- Maybe https://github.com/zed-industries/zed/issues/38252 (there might
be something going on with NPX too)
- Also addresses
https://github.com/zed-industries/zed/pull/39021#issuecomment-3644818347
### Why
Some more involved MCP servers timeout often, especially on first setup.
I got tired of having to set timeouts manually per server. I also
noticed a timeout could not be set for http context servers, which
causes Context7 or GitHub's remote servers to timeout at 60s sometimes.
### Overview
MCP Timeout Configuration Feature
This PR adds additional configurable timeout settings for Model Context
Protocol servers including a global timeout and the addition of timeouts
for http servers, addressing issues where servers were timing out after
a fixed 60 seconds regardless of user needs.
**Key Features:**
- **Global timeout setting** (`context_server_timeout`) - default
timeout for all MCP servers (default: 60s, max: 10min)
- **Per-server timeout overrides** - individual servers can specify
custom timeouts via `timeout` field
- **Precedence hierarchy** - per-server timeout > global timeout >
default (60s)
- **Automatic bounds checking** - enforces 10-minute maximum to prevent
resource exhaustion
- **Support for both transports** - works with stdio and HTTP-based
context servers
- **Comprehensive test coverage** - 3 new tests validating global,
override, and stdio timeout behavior
- **Full backward compatibility** - existing configurations work
unchanged with sensible defaults
### Release Notes:
- Added the ability to configure timeouts for context server tool calls.
The new global `context_server_timeout` setting controls the default
timeout (default is 60s, max: 10min). Additionally, per-server timeouts
can be configured using the `timeout` field within servers defined in
the `"context_servers" setting
---------
Co-authored-by: Ben Kunkle <ben@zed.dev>
## Summary
This PR adds support for the MCP (Model Context Protocol)
`notifications/tools/list_changed` notification, enabling dynamic tool
discovery when MCP servers add, remove, or modify their available tools
at runtime.
## Release Notes:
- Improved: MCP tools are now automatically reloaded when a context
server sends a `tools/list_changed` notification, eliminating the need
to restart the server to discover new tools.
## Changes
- Register a notification handler for `notifications/tools/list_changed`
in `ContextServerRegistry`
- Automatically reload tools when the notification is received
- Handler is registered both on initial server startup and when a server
transitions to `Running` status
## Motivation
The MCP specification includes a `notifications/tools/list_changed`
notification to inform clients when the list of available tools has
changed. Previously, Zed's agent would only load tools once when a
context server started. This meant that:
1. If an MCP server dynamically registered new tools after
initialization, they would not be available to the agent
2. The only way to refresh tools was to restart the entire context
server
3. Tools that were removed or modified would remain in the old state
until restart
## Implementation Details
The implementation follows these steps:
1. When a context server transitions to `Running` status, register a
notification handler for `notifications/tools/list_changed`
2. The handler captures a weak reference to the `ContextServerRegistry`
entity
3. When the notification is received, spawn a task that calls
`reload_tools_for_server` with the server ID
4. The existing `reload_tools_for_server` method handles fetching the
updated tool list and notifying observers
This approach is minimal and reuses existing tool-loading
infrastructure.
## Testing
- [x] Code compiles with `./script/clippy -p agent`
- The notification handler infrastructure already exists and is tested
in the codebase
- The `reload_tools_for_server` method is already tested and working
## Benefits
- Improves developer experience by enabling hot-reloading of MCP tools
- Aligns with the MCP specification's capability negotiation system
- No breaking changes to existing functionality
- Enables more flexible and dynamic MCP server implementations
## Related Issues
This implements part of the MCP specification that was already defined
in the type system but not wired up to actually handle the
notifications.
---------
Co-authored-by: Agus Zubiaga <agus@zed.dev>
### What this solves
This PR adds support for HTTP and SSE (Server-Sent Events) transports to
Zed's context server implementation, enabling communication with remote
MCP servers. Currently, Zed only supports local MCP servers via stdio
transport. This limitation prevents users from:
- Connecting to cloud-hosted MCP servers
- Using MCP servers running in containers or on remote machines
- Leveraging MCP servers that are designed to work over HTTP/SSE
### Why it's important
The MCP (Model Context Protocol) specification includes HTTP/SSE as
standard transport options, and many MCP server implementations are
being built with these transports in mind. Without this support, Zed
users are limited to a subset of the MCP ecosystem. This is particularly
important for:
- Enterprise users who need to connect to centralized MCP services
- Developers working with MCP servers that require network isolation
- Users wanting to leverage cloud-based context providers (e.g.,
knowledge bases, API integrations)
### Implementation approach
The implementation follows Zed's existing architectural patterns:
- **Transports**: Added `HttpTransport` and `SseTransport` to the
`context_server` crate, built on top of the existing `http_client` crate
- **Async handling**: Uses `gpui::spawn` for network operations instead
of introducing a new Tokio runtime
- **Settings**: Extended `ContextServerSettings` enum with a `Remote`
variant to support URL-based configuration
- **UI**: Updated the agent configuration UI with an "Add Remote Server"
option and dedicated modal for remote server management
### Changes included
- [x] HTTP transport implementation with request/response handling
- [x] SSE transport for server-sent events streaming
- [x] `build_transport` function to construct appropriate transport
based on URL scheme
- [x] Settings system updates to support remote server configuration
- [x] UI updates for adding/editing remote servers
- [x] Unit tests using `FakeHttpClient` for both transports
- [x] Integration tests (WIP)
- [x] Documentation updates (WIP)
### Testing
- Unit tests for both `HttpTransport` and `SseTransport` using mocked
HTTP client
- Manual testing with example MCP servers over HTTP/SSE
- Settings validation and UI interaction testing
### Screenshots/Recordings
[TODO: Add screenshots of the new "Add Remote Server" UI and
configuration modal]
### Example configuration
Users can now configure remote MCP servers in their `settings.json`:
```json
{
"context_servers": {
"my-remote-server": {
"enabled": true,
"url": "http://localhost:3000/mcp"
}
}
}
```
### AI assistance disclosure
I used AI to help with:
- Understanding the MCP protocol specification and how HTTP/SSE
transports should work
- Reviewing Zed's existing patterns for async operations and suggesting
consistent approaches
- Generating boilerplate for test cases
- Debugging SSE streaming issues
All code has been manually reviewed, tested, and adapted to fit Zed's
architecture. The core logic, architectural decisions, and integration
with Zed's systems were done with human understanding of the codebase.
AI was primarily used as a reference tool and for getting unstuck on
specific technical issues.
Release notes:
* You can now configure MCP Servers that connect over HTTP in your
settings file. These are not yet available in the extensions API.
```
{
"context_servers": {
"my-remote-server": {
"enabled": true,
"url": "http://localhost:3000/mcp"
}
}
}
```
---------
Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>
Co-Authored-By: Ben K <ben@zed.dev>
Co-Authored-By: Anthony <anthony@zed.dev>
Co-Authored-By: Mikayla <mikayla@zed.dev>
Release Notes:
- settings: Major internal changes to settings. The primary user-facing
effect is that some settings which did not make sense in project
settings files are no-longer read from there. (For example the inline
blame settings)
---------
Co-authored-by: Ben Kunkle <ben@zed.dev>
Co-authored-by: Mikayla Maki <mikayla.c.maki@gmail.com>
Co-authored-by: Anthony <anthony@zed.dev>
Closes: #32668
- Add
[tool_call_timeout_millis](https://github.com/cline/cline/pull/1904)
field to ContextServerCommand, like in Cline
- Update ModelContextServerBinary to include timeout configuration
- Modify Client to store and use configurable request timeout
- Replace hardcoded REQUEST_TIMEOUT with self.request_timeout
- Rename REQUEST_TIMEOUT to DEFAULT_REQUEST_TIMEOUT for clarity
- Maintain backward compatibility with 60-second default
Release Notes:
- context_server: Add support for configurable timeout for MCP tool
calls
---------
Co-authored-by: Ben Brandt <benjamin.j.brandt@gmail.com>
This fixes an issue where we were not setting the context server working
directory at all.
Release Notes:
- Context servers will now be spawned in the currently active project
root.
---------
Co-authored-by: Danilo Leal <danilo@zed.dev>
This changes the context server crate so that the input/output for a
request are encoded at the type level, similar to how it is done for LSP
requests.
This also makes it easier to write tests that mock context servers, e.g.
you can write something like this now when using the `test-support`
feature of the `context-server` crate:
```rust
create_fake_transport("mcp-1", cx.background_executor())
.on_request::<context_server::types::request::PromptsList>(|_params| {
PromptsListResponse {
prompts: vec![/* some prompts */],
..
}
})
```
Release Notes:
- N/A
Because we instantiated `ContextServerManager` both in `agent` and
`assistant-context-editor`, and these two entities track the running MCP
servers separately, we were effectively running every MCP server twice.
This PR moves the `ContextServerManager` into the project crate (now
called `ContextServerStore`). The store can be accessed via a project
instance. This ensures that we only instantiate one `ContextServerStore`
per project.
Also, this PR adds a bunch of tests to ensure that the
`ContextServerStore` behaves correctly (Previously there were none).
Closes#28714Closes#29530
Release Notes:
- N/A
This PR abstracts the communication layer for context servers, laying
the groundwork for supporting multiple transport mechanisms and taking
one step towards enabling remote servers.
Key changes centre around creating a new `Transport` trait with methods
for sending and receiving messages. I've implemented this trait for the
existing stdio-based communication, which is now encapsulated in a
`StdioTransport` struct. The `Client` struct has been refactored to use
this new `Transport` trait instead of directly managing stdin and
stdout.
The next steps will involve implementing an SSE + HTTP transport and
defining alternative context server settings for remote servers.
Release Notes:
- N/A
---------
Co-authored-by: Marshall Bowers <git@maxdeviant.com>
There's still a bit more work to do on this, but this PR is compiling
(with warnings) after eliminating the key types. When the tasks below
are complete, this will be the new narrative for GPUI:
- `Entity<T>` - This replaces `View<T>`/`Model<T>`. It represents a unit
of state, and if `T` implements `Render`, then `Entity<T>` implements
`Element`.
- `&mut App` This replaces `AppContext` and represents the app.
- `&mut Context<T>` This replaces `ModelContext` and derefs to `App`. It
is provided by the framework when updating an entity.
- `&mut Window` Broken out of `&mut WindowContext` which no longer
exists. Every method that once took `&mut WindowContext` now takes `&mut
Window, &mut App` and every method that took `&mut ViewContext<T>` now
takes `&mut Window, &mut Context<T>`
Not pictured here are the two other failed attempts. It's been quite a
month!
Tasks:
- [x] Remove `View`, `ViewContext`, `WindowContext` and thread through
`Window`
- [x] [@cole-miller @mikayla-maki] Redraw window when entities change
- [x] [@cole-miller @mikayla-maki] Get examples and Zed running
- [x] [@cole-miller @mikayla-maki] Fix Zed rendering
- [x] [@mikayla-maki] Fix todo! macros and comments
- [x] Fix a bug where the editor would not be redrawn because of view
caching
- [x] remove publicness window.notify() and replace with
`AppContext::notify`
- [x] remove `observe_new_window_models`, replace with
`observe_new_models` with an optional window
- [x] Fix a bug where the project panel would not be redrawn because of
the wrong refresh() call being used
- [x] Fix the tests
- [x] Fix warnings by eliminating `Window` params or using `_`
- [x] Fix conflicts
- [x] Simplify generic code where possible
- [x] Rename types
- [ ] Update docs
### issues post merge
- [x] Issues switching between normal and insert mode
- [x] Assistant re-rendering failure
- [x] Vim test failures
- [x] Mac build issue
Release Notes:
- N/A
---------
Co-authored-by: Antonio Scandurra <me@as-cii.com>
Co-authored-by: Cole Miller <cole@zed.dev>
Co-authored-by: Mikayla <mikayla@zed.dev>
Co-authored-by: Joseph <joseph@zed.dev>
Co-authored-by: max <max@zed.dev>
Co-authored-by: Michael Sloan <michael@zed.dev>
Co-authored-by: Mikayla Maki <mikaylamaki@Mikaylas-MacBook-Pro.local>
Co-authored-by: Mikayla <mikayla.c.maki@gmail.com>
Co-authored-by: joão <joao@zed.dev>
This PR factors the tool definitions out of the `assistant` crate so
that they can be shared between `assistant` and `assistant2`.
`ToolWorkingSet` now lives in `assistant_tool`. The tool definitions
themselves live in `assistant_tools`, with the exception of the
`ContextServerTool`, which has been moved to the `context_server` crate.
As part of this refactoring I needed to extract the
`ContextServerSettings` to a separate `context_server_settings` crate so
that the `extension_host`—which is referenced by the `remote_server`—can
name the `ContextServerSettings` type without pulling in some undesired
dependencies.
Release Notes:
- N/A
