Resolve compaction policy per routed model

packages/compact/compact-basic/tests/compact-loop-repro.spec.ts

@@ -37,6 +37,10 @@ class StepwiseToolAdapter extends LlmAdapter {
     super()
   }
 
+  override resolveModelContext(): Promise<{ contextWindow: number }> {
+    return Promise.resolve({ contextWindow: 400 })
+  }
+
   async * stream(_options: GenerateOptions): AsyncIterable<StreamChunk> {
     const n = this.calls
     this.calls += 1
@@ -65,6 +69,10 @@ class OverflowRecoveryAdapter extends LlmAdapter {
     super()
   }
 
+  override resolveModelContext(): Promise<{ contextWindow: number }> {
+    return Promise.resolve({ contextWindow: 128 })
+  }
+
   override async * stream(options: GenerateOptions): AsyncIterable<StreamChunk> {
     if (options.system?.includes('You are a compaction engine')) {
       this.summaryRequests.push(options)
@@ -100,7 +108,7 @@ async function harness(toolSteps: number): Promise<{ ctx: Context; compact: Repr
   await mountAgentLoopTestDependencies(ctx)
   await ctx.plugin(Invariants)
   await ctx.plugin(AgentLoop, { agents: [] })
-  await ctx.plugin(TokenMeterService, { contextWindow: 400 })
+  await ctx.plugin(TokenMeterService)
   ctx.llm.registerAdapter(['mock'], new StepwiseToolAdapter(toolSteps))
   ctx.tools.register(defineTool({
     name: 'work',
@@ -225,7 +233,7 @@ describe('context-overflow recovery across the real loop and compact-basic', ()
       await mountAgentLoopTestDependencies(ctx)
       await ctx.plugin(Invariants)
       await ctx.plugin(AgentLoop, { agents: [] })
-      await ctx.plugin(TokenMeterService, { contextWindow: 128 })
+      await ctx.plugin(TokenMeterService)
       ctx.llm.registerAdapter(['mock'], adapter)
       ctx.on('agent/request', async (_agent, _turn, _step, config) => ({ ...config, provider: 'mock', model: 'mock' }))
       await ctx.plugin(BasicCompactService, {