agentHost: refresh model catalogs periodically

[roblourens]

Summary

• refresh Agent Host provider model catalogs every 10 minutes from a single host-owned scheduler
• coalesce periodic refreshes while preserving forced refreshes for token, transport, usage-source, and client-generation changes
• refresh Copilot models after CLI restart and prevent stale same-token responses from the previous client generation from publishing
• preserve last-known-good Claude, Codex, and Copilot catalogs after transient refresh failures

Fixes #327413.

Validation

• TypeScript typecheck
• npm run valid-layers-check
• staged-file precommit hygiene
• full Agent Host unit suite: 3427 passing, 0 failing

(Written by Copilot)

[Copilot]

Pull request overview

Note

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This PR adds a host-owned periodic scheduler to refresh agent provider model catalogs, while updating providers to coalesce overlapping refreshes, guard against stale writes across client/token generations, and retain last-known-good catalogs on transient failures.

Changes:

• Introduces AgentModelRefreshScheduler and wires it into agent host startup to trigger periodic refreshModels across providers.
• Updates Copilot/Claude/Codex agents to coalesce concurrent refreshes, handle client-generation invalidation, and keep last-known-good catalogs on refresh failures.
• Adds/extends unit tests covering scheduler behavior, coalescing, stale in-flight drops, and last-known-good preservation.

Show a summary per file

File	Description
src/vs/platform/agentHost/node/agentModelRefreshScheduler.ts	New periodic scheduler that triggers provider refreshModels on a fixed interval.
src/vs/platform/agentHost/node/agentHostMain.ts	Installs the scheduler for process-lifetime periodic refreshes.
src/vs/platform/agentHost/node/agentHostServerMain.ts	Installs the scheduler in the server entrypoint as well.
src/vs/platform/agentHost/node/agentService.ts	Exposes an observable of registered agents for background jobs like the scheduler.
src/vs/platform/agentHost/common/agentService.ts	Extends the IAgent contract with optional, non-rejecting refreshModels.
src/vs/platform/agentHost/node/copilot/copilotAgent.ts	Adds refresh coalescing, client-generation invalidation, and forced refresh semantics.
src/vs/platform/agentHost/node/claude/claudeAgent.ts	Adds refresh coalescing and retains last-known-good models on transient failures.
src/vs/platform/agentHost/node/codex/codexAgent.ts	Adds refresh coalescing and preserves last-known-good model catalogs on failures.
src/vs/platform/agentHost/test/node/agentModelRefreshScheduler.test.ts	New unit tests validating scheduler ticking, dispose behavior, and fault tolerance.
src/vs/platform/agentHost/test/node/copilotAgent.test.ts	Enhances test client to gate responses; adds tests for coalescing, restart refresh, and stale-flight dropping.
src/vs/platform/agentHost/test/node/claudeAgent.test.ts	Adds tests for refresh coalescing and last-known-good model retention.
src/vs/platform/agentHost/test/node/codex/codexModelRefresh.test.ts	Adds a Codex regression test ensuring last-known-good models persist on periodic failure.

Review details

• Files reviewed: 12/12 changed files
• Comments generated: 2
• Review effort level: Low

[vs-code-engineering]

📬 CODENOTIFY

The following users are being notified based on files changed in this PR:

@TylerLeonhardt

Matched files:

• src/vs/platform/agentHost/node/claude/claudeAgent.ts