agentHost: fix Claude agent window showing only Haiku 4.5 in model picker

[Bappoz]

Descrição:

Fixes #316454
Related: anthropics/claude-code#59136

Problem

The Claude agent window (agents-window) model picker shows only Claude Haiku 4.5,
while the normal Claude Code window correctly shows all available models (Sonnet 4.6,
Opus 4.8, Haiku 4.5, etc.).

Root Cause

Two code paths exist for populating the Claude model list:

Normal Claude Code window (extension path):

• ClaudeCodeModels fetches via endpointProvider.getAllChatEndpoints()
• modelMetadataFetcher applies the copilotchat.showInModelPicker A/B experiment
  override, which sets showInModelPicker = true for models CAPI has as false
• Result: all capable Claude models are shown

Claude agent window (agent host path):

• ClaudeAgent._refreshModels() fetches directly from copilotApiService.models()
  (raw CAPI response)
• isClaudeModel() required model_picker_enabled: true from the raw CAPI value —
  with no experiment override applied
• Result: only models CAPI explicitly flags as picker-eligible (Haiku 4.5) are shown

CAPI /models
│
├── Extension path → modelMetadataFetcher → showInModelPicker override → ALL models ✓
│
└── Agent host path → isClaudeModel() → raw model_picker_enabled → only Haiku 4.5 ✗

Fix

Removed the !!m.model_picker_enabled check from isClaudeModel() in
src/vs/platform/agentHost/node/claude/claudeAgent.ts.

Root Cause

Two code paths exist for populating the Claude model list:

Normal Claude Code window (extension path):

• ClaudeCodeModels fetches via endpointProvider.getAllChatEndpoints()
• modelMetadataFetcher applies the copilotchat.showInModelPicker A/B experiment
  override, which sets showInModelPicker = true for models CAPI has as false
• Result: all capable Claude models are shown

Claude agent window (agent host path):

• ClaudeAgent._refreshModels() fetches directly from copilotApiService.models()
  (raw CAPI response)
• isClaudeModel() required model_picker_enabled: true from the raw CAPI value —
  with no experiment override applied
• Result: only models CAPI explicitly flags as picker-eligible (Haiku 4.5) are shown

CAPI /models
│
├── Extension path → modelMetadataFetcher → showInModelPicker override → ALL models ✓
│
└── Agent host path → isClaudeModel() → raw model_picker_enabled → only Haiku 4.5 ✗

Fix

Removed the !!m.model_picker_enabled check from isClaudeModel() in
src/vs/platform/agentHost/node/claude/claudeAgent.ts.

The agent host has no access to the experiment service that drives the override.
The remaining four conditions are sufficient guards against synthetic or ineligible entries:

Condition	Guards against
vendor === 'Anthropic'	Non-Anthropic models (e.g. GPT-5, auto)
supported_endpoints.includes('/v1/messages')	Models without Messages API support
capabilities.supports.tool_calls	Models that cannot run tools
tryParseClaudeModelId(id) !== undefined	Synthetic IDs like nectarine, auto

Changes

• src/vs/platform/agentHost/node/claude/claudeAgent.ts — removed !!m.model_picker_enabled
  from isClaudeModel(); updated JSDoc explaining why the flag is intentionally excluded
• src/vs/platform/agentHost/test/node/claudeAgent.test.ts — updated three test assertions

CAPI /models
│
├── Extension path → modelMetadataFetcher → showInModelPicker override → ALL models ✓
│
└── Agent host path → isClaudeModel() → raw model_picker_enabled → only Haiku 4.5 ✗

Fix

Removed the !!m.model_picker_enabled check from isClaudeModel() in
src/vs/platform/agentHost/node/claude/claudeAgent.ts.

The agent host has no access to the experiment service that drives the override.
The remaining four conditions are sufficient guards against synthetic or ineligible entries:

Condition	Guards against
vendor === 'Anthropic'	Non-Anthropic models (e.g. GPT-5, auto)
supported_endpoints.includes('/v1/messages')	Models without Messages API support
capabilities.supports.tool_calls	Models that cannot run tools
tryParseClaudeModelId(id) !== undefined	Synthetic IDs like nectarine, auto

Changes

• src/vs/platform/agentHost/node/claude/claudeAgent.ts — removed !!m.model_picker_enabled
  from isClaudeModel(); updated JSDoc explaining why the flag is intentionally excluded
• src/vs/platform/agentHost/test/node/claudeAgent.test.ts — updated three test assertions
  to reflect that model_picker_enabled: false models now correctly appear in the agent
  window picker

Testing

Unit tests

The existing test suite covers the fix directly. Key tests updated:

• 'authenticate populates models filtered to Claude family' — now asserts that
  ANTHROPIC_PICKER_DISABLED (claude-opus-4.5, model_picker_enabled: false) appears
  alongside the other Claude models
• 'model filter excludes non-Claude entries' — confirms non-Anthropic, no-tool-calls,
  and no-messages-endpoint models are still excluded
  | capabilities.supports.tool_calls | Models that cannot run tools |
  | tryParseClaudeModelId(id) !== undefined | Synthetic IDs like nectarine, auto |

Changes

• src/vs/platform/agentHost/node/claude/claudeAgent.ts — removed !!m.model_picker_enabled
  from isClaudeModel(); updated JSDoc explaining why the flag is intentionally excluded
• src/vs/platform/agentHost/test/node/claudeAgent.test.ts — updated three test assertions
  to reflect that model_picker_enabled: false models now correctly appear in the agent
  window picker

Testing

Unit tests

The existing test suite covers the fix directly. Key tests updated:

• 'authenticate populates models filtered to Claude family' — now asserts that
  ANTHROPIC_PICKER_DISABLED (claude-opus-4.5, model_picker_enabled: false) appears
  alongside the other Claude models
• 'model filter excludes non-Claude entries' — confirms non-Anthropic, no-tool-calls,
  and no-messages-endpoint models are still excluded
• 'authenticate retries proxy startup after a transient failure' — updated model ID
  list to include the formerly-excluded model

npm run test-node -- --run src/vs/platform/agentHost/test/node/claudeAgent.test.ts

Before — Claude agent window model picker (only Haiku 4.5):

After — tests are passing :

Related

• Tracking issue: Claude agent window model selection limited to Haiku 4.5 in VS Code Insiders #316454
• Upstream report: Agent window model selection limited to Haiku 4.5 in VS Code Insiders anthropics/claude-code#59136
• Normal window model fetch path:
  extensions/copilot/src/extension/chatSessions/claude/node/claudeCodeModels.ts
• Agent host model fetch path:
  src/vs/platform/agentHost/node/claude/claudeAgent.ts (_refreshModels)
• Experiment override that the agent host cannot access:
  extensions/copilot/src/platform/endpoint/node/modelMetadataFetcher.ts
  (_getShowInModelPickerOverride)

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Updates Claude model filtering in the agent host to align with Copilot extension behavior by no longer filtering on model_picker_enabled, and adjusts tests/fixtures accordingly.

Changes:

• Remove model_picker_enabled as a filter criterion in isClaudeModel.
• Expand test expectations to include an Anthropic model that has model_picker_enabled:false (e.g., claude-opus-4.5).
• Add explanatory comments in tests and implementation about why the flag is ignored.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/vs/platform/agentHost/node/claude/claudeAgent.ts	Removes model_picker_enabled gating and documents rationale in isClaudeModel.
src/vs/platform/agentHost/test/node/claudeAgent.test.ts	Updates assertions to include the additional Claude model and clarifies intent via comments.

Comments suppressed due to low confidence (1)

src/vs/platform/agentHost/test/node/claudeAgent.test.ts:1

• This assertion snapshots the full model objects including presentation fields (name) and internal metadata (_meta.multiplierNumeric), which makes the test brittle to unrelated catalog/telemetry changes. If the intent is purely “Claude-family models are included (including picker-disabled ones)”, consider asserting on model IDs (and optionally key capability fields) rather than the entire object shape.

/*---------------------------------------------------------------------------------------------

[Bappoz]

• ownership

@microsoft-github-policy-service agree