test(web-search): adapt fixtures to master's model selection and projections

Master moved the step's model route into the assembly context: the agent loop
fixes it per step and registers the prompt's provider variable from it, and
installModelSelection no longer takes a mutable selection. The tool-web
readiness fixture now registers that variable and passes the step's
modelSelection to each assembly.

AgentRegistry now needs the session projection registry, so the
web-search-deepseek initiator fixtures and the Loader composition in
chat-endpoint.spec.ts mount it, as master's own fixtures in this package do.

packages/web/tool-web/tests/tool-web.spec.ts

@@ -1,6 +1,6 @@
 import { afterEach, describe, expect, it, vi } from 'vitest'
 import { Context } from '@deepseek-ai/cordis'
-import { installModelSelection, type ModelSelectionRef } from '@deepseek-ai/dsh-agent'
+import type { ModelSelection } from '@deepseek-ai/dsh-agent'
 import { createScope, type Scope } from '@deepseek-ai/dsh-scope'
 import TurndownService from 'turndown'
 import { ToolCallId } from '@deepseek-ai/dsh-llm'
@@ -1086,26 +1086,23 @@ describe('web_search offering per model request', () => {
   }
 
   /**
-   * Mount the real prompt, tool, and web services with tool-web. Model selection is
-   * installed first, the order a tool-web reload produces once a Session exists.
+   * Mount the real prompt, tool, and web services with tool-web. The prompt's `provider`
+   * variable comes from the step's model selection, as the agent loop registers it.
    * @param setup - registered providers, the configured search provider, and the selected route.
-   * @returns the Session's model selection, tool-web's fiber, and a reader for one model request.
+   * @returns the step's model selection, tool-web's fiber, and a reader for one model request.
    */
   async function compose(setup: { providers: WebSearchProvider[]; searchProvider?: string; route?: string }) {
     const ctx = new Context()
     mounted.push(ctx)
-    const selection: ModelSelectionRef = {
-      current: { provider: setup.route ?? 'deepseek-official', model: 'deepseek-v4-flash' },
-      assembled: undefined,
-    }
-    installModelSelection(ctx, selection)
+    const selection: ModelSelection = { provider: setup.route ?? 'deepseek-official', model: 'deepseek-v4-flash' }
     await ctx.plugin(SystemPrompt)
+    ctx.systemPrompt.variable('provider', context => context.modelSelection?.provider)
     await ctx.plugin(ToolRuntime)
     await ctx.plugin(WebRuntime, setup.searchProvider === undefined ? {} : { searchProvider: setup.searchProvider })
     for (const provider of setup.providers) ctx.web.registerSearchProvider(provider)
     const fiber = await ctx.plugin(ToolWeb, {})
     const request = async (): Promise<{ tools: string[]; prompt: string }> => {
-      const assembly = await ctx.systemPrompt.assemble({})
+      const assembly = await ctx.systemPrompt.assemble({ modelSelection: { ...selection } })
       return { tools: assembly.tools.map(tool => tool.name), prompt: renderPrompt(assembly) }
     }
     return { ctx, selection, fiber, request }
@@ -1141,9 +1138,9 @@ describe('web_search offering per model request', () => {
   it('follows the model selected for each request', async () => {
     const { selection, request } = await compose({ providers: [routeProvider('deepseek', ['deepseek-account'])], route: 'deepseek-account' })
     expect((await request()).tools).toContain('web_search')
-    selection.current = { provider: 'deepseek-official', model: 'deepseek-v4-flash' }
+    selection.provider = 'deepseek-official'
     expect((await request()).tools).not.toContain('web_search')
-    selection.current = { provider: 'deepseek-account', model: 'deepseek-v4-flash' }
+    selection.provider = 'deepseek-account'
     expect((await request()).tools).toContain('web_search')
   })
 

packages/web/web-search-deepseek/tests/chat-endpoint.spec.ts

@@ -17,6 +17,7 @@ import { createLaunchEnvironmentSnapshot } from '@deepseek-ai/dsh-launch-environ
 import LlmRuntime from '@deepseek-ai/dsh-llm'
 import * as Official from '@deepseek-ai/dsh-llm-deepseek-api-key'
 import SessionStore, { SessionId } from '@deepseek-ai/dsh-session'
+import SessionProjectionRegistry from '@deepseek-ai/dsh-session-projection'
 import WebRuntime from '@deepseek-ai/dsh-web'
 import * as deepseekPlugin from '@deepseek-ai/dsh-web-search-deepseek'
 
@@ -55,6 +56,7 @@ async function compose(composition: Composition): Promise<Context> {
   const rows = [
     { id: 'llm', name: '@deepseek-ai/dsh-llm' },
     { id: 'session', name: '@deepseek-ai/dsh-session' },
+    { id: 'session-projection', name: '@deepseek-ai/dsh-session-projection' },
     { id: 'agents', name: '@deepseek-ai/dsh-agent' },
     {
       id: 'llm-deepseek', name: '@deepseek-ai/dsh-llm-deepseek-api-key',
@@ -67,6 +69,7 @@ async function compose(composition: Composition): Promise<Context> {
   await writeFile(configPath, JSON.stringify(rows))
   const modules = new Map<string, unknown>([
     ['@deepseek-ai/dsh-llm', LlmRuntime], ['@deepseek-ai/dsh-session', SessionStore],
+    ['@deepseek-ai/dsh-session-projection', SessionProjectionRegistry],
     ['@deepseek-ai/dsh-agent', AgentRegistry], ['@deepseek-ai/dsh-llm-deepseek-api-key', Official],
     ['@deepseek-ai/dsh-web', WebRuntime], ['@deepseek-ai/dsh-web-search-deepseek', deepseekPlugin],
   ])

packages/web/web-search-deepseek/tests/deepseek.spec.ts

@@ -913,6 +913,7 @@ describe('web-search-deepseek search readiness', () => {
     expect(await ctx.web.searchReady('deepseek-account')).toBe(false)
     // A search on that route reads the same grant before any key and fails instead of trying the key.
     await ctx.plugin(SessionStore)
+    await ctx.plugin(SessionProjectionRegistry)
     await ctx.plugin(AgentRegistry)
     const session = ctx.sessions.create(SessionId('web-search-unreadable-grant'))
     session.append('turn/start', { turn: 1 })
@@ -939,6 +940,7 @@ describe('web-search-deepseek route policy', () => {
     const ctx = new Context()
     try {
       await ctx.plugin(SessionStore)
+      await ctx.plugin(SessionProjectionRegistry)
       await ctx.plugin(AgentRegistry)
       await ctx.plugin(WebRuntime, { searchProvider: DEEPSEEK_PROVIDER_ID })
       await ctx.plugin(deepseekPlugin, config)