Throw AuthRequired from CopilotAgent.listSessions before auth

[roblourens]

Problem

Agent-host sessions returned by listSessions() did not appear in the Agents sidebar on fresh launch. They only showed up after the user sent a message — at which point a notify/sessionAdded would force the renderer to call getSessions() again, which would then return the real list.

Root cause

CopilotAgent.listSessions() (and _listModels()) silently returned [] whenever _githubToken was unset. On a fresh launch the renderer's eager _refreshSessions() ran before the auth token was resolved, so it cached an empty list. BaseAgentHostSessionsProvider._ensureSessionCache() is one-shot, so it never retried. On reload it appeared to work because the token was already cached and auth completed synchronously fast.

This also violates the AHP contract — per docs/specification/authentication.md, an agent declaring protectedResources with required: true MUST throw AuthRequired (-32007) when used unauthenticated, not lie by returning empty data.

Fix

Server side (copilotAgent.ts):

• listSessions() and _listModels() no longer early-return []. They go through _ensureClient(), which already throws ProtocolError(AHP_AUTH_REQUIRED, ...) when no token is present.
• _refreshModels() already guards on !_githubToken and catches errors, so it remains correct.

Renderer side (localAgentHostSessionsProvider.ts):

• The existing autorun(authenticationPending) triggers _refreshSessions() exactly once when auth settles. This is the natural retry mechanism for the silent listSessions case.
• The existing bare catch in _refreshSessions swallows the auth error — appropriate here, since unlike createSession we should NOT prompt the user to sign in just to render the sidebar.
• This is consistent with the existing _isAuthRequiredError pattern in agentHostSessionHandler.ts; it differs only in retry strategy: createSession prompts interactively, listSessions waits for the in-flight auth attempt to settle.

Tests

• Updated copilotAgent.test.ts "returns empty models and throws AuthRequired for sessions before authentication" to expect the throw.
• New localAgentHostSessionsProvider.test.ts tests:
  • eagerly populates and fires onDidChangeSessions after construction without a getSessions() call
  • defers eager session list fetch until authentication settles
• All 13 copilotAgent + 41 localAgentHostSessionsProvider tests pass; full typecheck clean.

(Written by Copilot)

[github-actions]

Screenshot Changes

Base: df49d483 Current: a5ab6e16

Changed (10)

chat/aiCustomizations/aiCustomizationManagementEditor/McpBrowseMode/Light

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editor/inlineChatAffordance/InlineChatOverlay/Light

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agentSessionsViewer/CompletedRead/Dark

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agentSessionsViewer/CompletedRead/Light

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agentSessionsViewer/WithFileChangesList/Dark

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agentSessionsViewer/WithFileChangesList/Light

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agentSessionsViewer/CloudProvider/Dark

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agentSessionsViewer/CloudProvider/Light

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agentSessionsViewer/BackgroundProvider/Dark

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agentSessionsViewer/BackgroundProvider/Light

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[Copilot]

Pull request overview

Fixes an Agents sidebar startup issue where listSessions() could return an empty list before authentication completed, causing the renderer to cache “no sessions” and never retry. The change aligns Copilot’s agent-host implementation with the AHP authentication contract by throwing AuthRequired when unauthenticated, and adds a renderer-side eager refresh that waits for the initial auth pass to settle.

Changes:

• Server: CopilotAgent.listSessions() / _listModels() now go through _ensureClient() and throw AuthRequired when unauthenticated (instead of returning []).
• Renderer: LocalAgentHostSessionsProvider eagerly refreshes sessions once authenticationPending settles.
• Tests updated/added to validate the new auth-required behavior and the eager-refresh flow.

Show a summary per file

File	Description
src/vs/platform/agentHost/node/copilot/copilotAgent.ts	Removes unauthenticated “return []” behavior so listSessions/_listModels correctly throw AuthRequired.
src/vs/platform/agentHost/test/node/copilotAgent.test.ts	Updates expectations to assert listSessions() rejects with AuthRequired before authentication.
src/vs/sessions/contrib/agentHost/browser/localAgentHostSessionsProvider.ts	Adds an autorun to refresh/populate the session cache after the initial auth pass settles.
src/vs/sessions/contrib/agentHost/test/browser/localAgentHostSessionsProvider.test.ts	Adds coverage for eager session population and for deferring the eager refresh until auth settles.

Copilot's findings

• Files reviewed: 4/4 changed files
• Comments generated: 0