Record the cost of sessions that use a custom Responses endpoint

agents/codelayer/src/agent.ts

@@ -2,6 +2,7 @@ import type { LanguageModel, JSONValue } from 'ai'
 import { createHash } from 'node:crypto'
 import {
 	Agent,
+	CUSTOM_RESPONSES_PROVIDER,
 	doomLoop,
 	tarsPersona,
 	type AgentConfig,
@@ -218,7 +219,7 @@ export function buildProviderOptions(
 		fastMode: overrides.codex?.fastMode ?? false,
 		...overrides.codex,
 	}
-	const isCustomResponses = (model as { provider?: string }).provider === 'custom-openai-responses'
+	const isCustomResponses = (model as { provider?: string }).provider === CUSTOM_RESPONSES_PROVIDER
 	const openaiOptions = isCustomResponses
 		? (({ fastMode: _fastMode, serviceTier: _serviceTier, ...options }) => ({ ...options, forceReasoning: true }))(codexOptions)
 		: codexOptions

agents/codelayer/src/providers.ts

@@ -1,6 +1,7 @@
 import { createAnthropic } from '@ai-sdk/anthropic'
 import { createOpenAI } from '@ai-sdk/openai'
 import type { LanguageModel } from 'ai'
+import { CUSTOM_RESPONSES_PROVIDER } from '@humanlayer/agentlayer-core'
 import { ensureFileAuthStore, type AuthInfo } from '@humanlayer/agentlayer-provider-auth'
 import { createCopilotProvider } from '@humanlayer/agentlayer-provider-github-copilot'
 import {
@@ -275,7 +276,7 @@ function reportCustomResponsesError(options: {
 				error: safeMessage,
 				errorName: error.name,
 				operation: options.operation,
-				provider: 'custom-openai-responses',
+				provider: CUSTOM_RESPONSES_PROVIDER,
 				statusCode,
 			},
 		})
@@ -302,7 +303,7 @@ export function createCustomCodexResponsesModel(options: {
 			return await captureResponseUsage(response, rawUsage)
 		}
 		return createOpenAI({
-		name: 'custom-openai-responses',
+		name: CUSTOM_RESPONSES_PROVIDER,
 		baseURL: override.baseURL,
 		apiKey: override.apiKey,
 		fetch: requestFetch as typeof globalThis.fetch,
@@ -312,7 +313,7 @@ export function createCustomCodexResponsesModel(options: {
 
 	return {
 		specificationVersion: modelMetadata.specificationVersion,
-		provider: 'custom-openai-responses',
+		provider: CUSTOM_RESPONSES_PROVIDER,
 		modelId: selectedModelId,
 		supportedUrls: modelMetadata.supportedUrls,
 		doGenerate: async (request) => {

packages/agentlayer-core/src/index.ts

@@ -92,6 +92,7 @@ export {
 	toolResultMessage,
 	userMessage,
 } from './messages'
+export { CUSTOM_RESPONSES_PROVIDER } from './models'
 export { createOutputRenderer, type OutputRenderer, type OutputRendererOptions } from './output-renderer'
 export { getPendingToolCalls } from './pending'
 export * from './prompts'

packages/agentlayer-core/src/models.ts

@@ -55,6 +55,15 @@ export function getCodexContextWindow(modelId: string): number {
 	return CODEX_CONTEXT_WINDOWS[modelId as CodexModel] ?? CODEX_CONTEXT_WINDOWS['gpt-5.5']
 }
 
+/**
+ * Provider name for a user-supplied OpenAI-compatible Responses endpoint (Azure AI
+ * Foundry, or OpenAI direct). The models behind it are OpenAI catalog models, so the
+ * key must resolve to `openai` here — anything else silently costs nothing, because a
+ * pricing miss is reported as `undefined` rather than an error. CodeLayer builds the
+ * model with this exact name; import it from there rather than repeating the literal.
+ */
+export const CUSTOM_RESPONSES_PROVIDER = 'custom-openai-responses'
+
 const PROVIDER_LIMIT_OVERRIDES: Record<string, Partial<ModelLimits>> = {}
 
 function getProviderLimitOverride(modelKey: ModelKey): Partial<ModelLimits> | undefined {
@@ -108,8 +117,11 @@ export class ModelProvider {
 			// AI SDK provider keys include a suffix (e.g. "anthropic.messages", "openai.chat")
 			// but models.dev uses the base provider name (e.g. "anthropic", "openai")
 			const baseKey = rawProviderKey.split('.')[0]!
-			// Codex providers use custom names but their models are OpenAI models
-			const providerKey = baseKey.startsWith('codex') ? 'openai' : baseKey
+			// Codex providers use custom names but their models are OpenAI models. So is the model
+			// behind a custom Responses endpoint: CODELAYER_CODEX_MODEL renames it only on the wire,
+			// so modelId here is still the selected OpenAI catalog id.
+			const providerKey =
+				baseKey.startsWith('codex') || baseKey === CUSTOM_RESPONSES_PROVIDER ? 'openai' : baseKey
 
 			const provider = this.modelsData[providerKey]
 			if (!provider?.models) return undefined

packages/agentlayer-core/test/models.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, test } from 'bun:test'
-import { CODEX_CONTEXT_WINDOWS, type ModelKey, ModelProvider } from '../src/models'
+import { CODEX_CONTEXT_WINDOWS, CUSTOM_RESPONSES_PROVIDER, type ModelKey, ModelProvider } from '../src/models'
 
 describe('ModelProvider.getModelLimits', () => {
 	const provider = new ModelProvider()
@@ -35,6 +35,19 @@ describe('ModelProvider.getModelLimits', () => {
 		expect(limits?.output).toBe(128_000)
 	})
 
+	test('a custom Responses endpoint is priced as the OpenAI model it serves', () => {
+		// Regression: this key used to miss the catalog entirely, and a pricing miss is
+		// reported as `undefined`, so Azure AI Foundry sessions recorded tokens and no
+		// dollars at all — silently, and unrecoverably, since cost is frozen at ingest.
+		expect(provider.getModelPricing(`${CUSTOM_RESPONSES_PROVIDER}/gpt-5.6-sol`)).toMatchObject({
+			input: 5,
+			output: 30,
+		})
+
+		// The public Responses API, not the private Codex one, so it keeps the public window.
+		expect(provider.getModelLimits(`${CUSTOM_RESPONSES_PROVIDER}/gpt-5.6-sol`)?.context).toBe(1_050_000)
+	})
+
 	test('openai/gpt-5.6 keeps the public OpenAI API context window and pricing', () => {
 		const limits = provider.getModelLimits('openai/gpt-5.6-sol')