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Add an opt-in headless delegate lane behind the MCP bridge. This introduces delegate task management, launcher wiring, docs, and tests for remote headless Copilot workers. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Pull request overview
Adds an opt-in “headless delegate” lane to run longer autonomous Copilot work on a selected codespace, without changing the default remote_* workflow.
Changes:
- Introduces
internal/delegatewith a headless runner + task manager and a minimal JSON-RPC client forcopilot --headless --stdio. - Registers additive MCP tools (
delegate_task,read_delegate_task,cancel_delegate_task) behind--headless-delegate/CODESPACE_ENABLE_HEADLESS_DELEGATE. - Updates launcher/resume flows and instruction/agent generation to include a
@remote-delegateagent and delegate-aware docs.
Reviewed changes
Copilot reviewed 13 out of 13 changed files in this pull request and generated 3 comments.
Show a summary per file
| File | Description |
|---|---|
| internal/registry/registry.go | Adds UpdateBranch to refresh tracked branch metadata post-delegate. |
| internal/mcp/server.go | Conditionally registers delegate MCP tools when a delegate manager is configured. |
| internal/mcp/lifecycle.go | Extends LifecycleConfig to carry an optional DelegateManager. |
| internal/mcp/delegate.go | Implements the three delegate MCP tools and branch refresh on completion. |
| internal/mcp/server_test.go | Adds unit tests for delegate tool handlers via a fake task manager. |
| internal/delegate/manager.go | Adds in-memory task lifecycle tracking (start/read/cancel) with progress logging. |
| internal/delegate/headless.go | Implements a runner that starts a remote headless Copilot session over gh codespace ssh. |
| internal/delegate/rpc.go | Implements a simple JSON-RPC-over-stdio client used by the headless runner. |
| internal/delegate/headless_test.go | Adds coverage for command construction and task manager lifecycle/cancel behavior. |
| cmd/gh-copilot-codespace/main.go | Threads --headless-delegate through launcher/resume/config generation and enables delegate tools in MCP mode. |
| cmd/gh-copilot-codespace/main_test.go | Updates MCP config tests and adds coverage for delegate env + instruction/agent generation. |
| cmd/gh-copilot-codespace/integration_test.go | Updates calls for new buildMCPConfig signature. |
| README.md | Documents the new opt-in delegate lane and CLI flag. |
| case <-ctx.Done(): | ||
| return ctx.Err() | ||
| case resp := <-responseCh: |
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In rpcClient.Call, if ctx is canceled before a response arrives, the request stays in c.pending because the ctx.Done() branch returns without deleting it. This can leak pending entries indefinitely (and potentially accumulate goroutines/channels) if the remote never responds. Consider removing the pending entry on ctx.Done() and closing/draining the response channel to avoid later sends piling up.
| case <-ctx.Done(): | |
| return ctx.Err() | |
| case resp := <-responseCh: | |
| case <-ctx.Done(): | |
| // Context canceled before a response arrived: remove pending entry | |
| // and asynchronously drain any late response to avoid blocking the reader. | |
| c.mu.Lock() | |
| delete(c.pending, id) | |
| c.mu.Unlock() | |
| go func(ch <-chan rpcResponse) { | |
| select { | |
| case <-ch: | |
| default: | |
| } | |
| }(responseCh) | |
| return ctx.Err() | |
| case resp := <-responseCh: | |
| // Normal response path: remove pending entry now that we're done. | |
| c.mu.Lock() | |
| delete(c.pending, id) | |
| c.mu.Unlock() |
| type Manager struct { | ||
| mu sync.RWMutex | ||
| nextID int | ||
| now func() time.Time | ||
| runner Runner | ||
| tasks map[string]*taskState | ||
| } |
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Manager.tasks is an unbounded map and completed/failed/canceled tasks are never evicted. In a long-lived MCP session, repeated delegate_task usage can grow memory over time (snapshots also retain up to maxTaskLogBytes each). Consider adding a retention policy (max tasks / TTL) and pruning old terminal-state tasks, or exposing an explicit cleanup method.
| @@ -973,16 +1004,20 @@ func buildMCPConfigWithRegistry(selfBinary string, reg *registry.Registry, remot | |||
| }) | |||
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buildMCPConfigWithRegistry serializes Alias/Name/Repo/Branch/Workdir but not ManagedCodespace.ExecAgent. As a result, the MCP server process reconstructed from CODESPACE_REGISTRY can't pass an exec-agent path into delegate_task (and will always fall back to the bash -lc path), even if the launcher successfully deployed the exec agent. Consider including ExecAgent in the serialized registryEntry and wiring it through registryFromJSON.
See below for a potential fix:
Workdir: cs.Workdir,
ExecAgent: cs.ExecAgent,
|
@copilot Can you use copilot-sdk to integrate with |
Switch the headless delegate integration to use the officially documented Agent Client Protocol (ACP) with --acp --stdio instead of the deprecated --headless --stdio mode. Transport: Content-Length-framed JSON-RPC → NDJSON (one JSON per line) Protocol: session.create/send/event → initialize/session/new/session/prompt/session/update Handler: permission.request → requestPermission (ACP format) Also fix pending-entry goroutine leak on ctx cancellation and remove now-unused extractMessageContent/extractSessionError helpers. Co-authored-by: ekroon <123574+ekroon@users.noreply.github.com>
The In 760594d I migrated the delegate to use
This is functionally equivalent to what the copilot-sdk does under the hood, implemented natively in Go without any new dependencies. Warning Firewall rules blocked me from connecting to one or more addresses (expand for details)I tried to connect to the following addresses, but was blocked by firewall rules:
If you need me to access, download, or install something from one of these locations, you can either:
|
|
@copilot https://github.com/github/copilot-sdk/tree/main/go Is in go go get github.com/github/copilot-sdk/go Please do as I asked. |
…dk/go Co-authored-by: ekroon <123574+ekroon@users.noreply.github.com>
Done in 4fc794c. The SDK manages the copilot process and the
The custom Warning Firewall rules blocked me from connecting to one or more addresses (expand for details)I tried to connect to the following addresses, but was blocked by firewall rules:
If you need me to access, download, or install something from one of these locations, you can either:
|
What
--headless-delegateextra to the launcher and MCP configdelegate_task,read_delegate_task, andcancel_delegate_task@remote-delegateagentWhy
This starts the headless integration path without changing the default local-Copilot-frontend workflow. It adds a separate remote delegate lane for longer autonomous work on a codespace while keeping the existing
remote_*tools intact.How
internal/delegateusing the officialgithub.com/github/copilot-sdk/goSDK to run remotecopilot --headless --stdioovergh codespace sshgh codespace sshby settingCLIPath="gh"withCLIArgscontaining the SSH routing; the SDK appends--headless --no-auto-update --log-level error --stdiowhich SSH forwards as the remote commandcopilot.PermissionHandler.ApproveAllfor autonomous permission handling andsession.Onfor streaming assistant message and idle events--envflags; for the bash fallback,"$@"captures and forwards the SDK-appended flags tocopilot --yoloTesting
go build ./cmd/gh-copilot-codespacego vet ./...go test -race ./...💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.