Refactor enableThinking/reasoningEffort into IModelCapabilityOptions

[bhavyaus]

Port of microsoft/vscode-copilot-chat#5026.

Refactors flat enableThinking and reasoningEffort fields on IMakeChatRequestOptions into a single modelCapabilities?: IModelCapabilityOptions object. Also moves model capability check helpers (TOOL_SEARCH_SUPPORTED_MODELS, modelSupportsToolSearch, modelSupportsContextEditing) from anthropic.ts to chatModelCapabilities.ts, and adds supportsToolSearch/supportsContextEditing fields to IChatEndpoint so they can be set from server-side metadata.

[github-actions]

Screenshot Changes

Base: 7446c69a Current: 68659012

Changed (5)

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[Copilot]

Pull request overview

This PR refactors per-request “thinking” and related model-capability toggles from flat IMakeChatRequestOptions fields into a single modelCapabilities?: IModelCapabilityOptions object, and centralizes model capability detection (tool search + context editing) while allowing endpoints to expose these capabilities via server-provided metadata.

Changes:

• Introduces IModelCapabilityOptions and replaces enableThinking/reasoningEffort with modelCapabilities on IMakeChatRequestOptions.
• Moves tool-search/context-editing capability helpers into chatModelCapabilities.ts and adds supportsToolSearch/supportsContextEditing to IChatEndpoint.
• Updates request builders and tool-calling loops to plumb modelCapabilities through, plus adjusts related unit tests.

Show a summary per file

File	Description
extensions/copilot/src/platform/networking/common/networking.ts	Adds IModelCapabilityOptions and nests request capability opt-ins under modelCapabilities.
extensions/copilot/src/platform/networking/common/anthropic.ts	Switches capability checks to use shared helpers + endpoint metadata fields.
extensions/copilot/src/platform/endpoint/test/node/messagesApi.spec.ts	Updates tests to use modelCapabilities for thinking/effort.
extensions/copilot/src/platform/endpoint/node/responsesApi.ts	Reads reasoning effort from options.modelCapabilities.
extensions/copilot/src/platform/endpoint/node/messagesApi.ts	Gates tool search/context editing/thinking using modelCapabilities flags.
extensions/copilot/src/platform/endpoint/node/chatEndpoint.ts	Plumbs server metadata into endpoint capability fields; adjusts anthropic-beta header assembly.
extensions/copilot/src/platform/endpoint/common/endpointProvider.ts	Extends model metadata supports with tool_search / context_editing.
extensions/copilot/src/platform/endpoint/common/chatModelCapabilities.ts	Hosts centralized tool-search/context-editing capability logic/constants.
extensions/copilot/src/extension/tools/node/toolSearchTool.ts	Imports supported-model list from centralized capabilities module.
extensions/copilot/src/extension/prompt/node/searchSubagentToolCallingLoop.ts	Switches loop fetch plumbing to pass modelCapabilities.
extensions/copilot/src/extension/prompt/node/executionSubagentToolCallingLoop.ts	Switches loop fetch plumbing to pass modelCapabilities.
extensions/copilot/src/extension/prompt/node/defaultIntentRequestHandler.ts	Constructs per-request modelCapabilities (thinking/effort/tool search/context editing).
extensions/copilot/src/extension/intents/node/toolCallingLoop.ts	Updates fetch options typing and populates modelCapabilities (thinking).
extensions/copilot/src/extension/externalAgents/node/oaiLanguageModelServer.ts	Updates proxy request to enable thinking via modelCapabilities.
extensions/copilot/src/extension/conversation/vscode-node/languageModelAccess.ts	Moves reasoning effort into modelCapabilities.
extensions/copilot/src/extension/chatSessions/claude/node/claudeLanguageModelServer.ts	Updates proxy request to enable thinking via modelCapabilities.

Copilot's findings

• Files reviewed: 16/16 changed files
• Comments generated: 5