Refactor: Provider handler registry for extra-params.ts #25311
Description
Problem
extra-params.ts currently has multiple hardcoded provider checks:
if (provider === "anthropic") { ... }
if (provider === "amazon-bedrock" && ...) { ... }
if (provider === "openrouter") { ... }
if (provider === "zai" || provider === "z-ai") { ... }
if (provider === "moonshot" && sessionKey) { ... } // PR #25104As more providers add special handling, this pattern becomes harder to maintain.
Proposal
Replace hardcoded checks with a provider handler registry:
type ProviderHandler = {
createWrapper?: (baseStreamFn: StreamFn, config: unknown, ...args: unknown[]) => StreamFn;
enabledWhen?: (provider: string, config: Record<string, unknown>) => boolean;
};
const providerHandlers: Record<string, ProviderHandler> = {
moonshot: {
createWrapper: createMoonshotCacheWrapper,
enabledWhen: (_, config) => config.contextCache?.enabled === true,
},
openrouter: {
createWrapper: createOpenRouterWrapper,
enabledWhen: () => true,
},
// ...
};
// In applyExtraParamsToAgent:
for (const [name, handler] of Object.entries(providerHandlers)) {
if (provider === name && handler.enabledWhen?.(provider, merged)) {
agent.streamFn = handler.createWrapper?.(agent.streamFn, ...);
}
}Benefits
- Easier to add new providers
- Clearer separation of concerns
- Each provider's logic is self-contained
- Potentially config-driven in the future
Context
Discovered during PR #25104 (Moonshot context caching). Keeping current hardcoded approach for that PR to minimize scope.