feat(providers): add Sakana AI provider with Fugu models (#5169)

* feat(providers): add Sakana AI provider with Fugu models

OpenAI-compatible provider at https://api.sakana.ai/v1 (bearer auth).
Registers fugu (fast default) and fugu-ultra (reasoning flagship), both
1M context. BYOK-only, never hosted/auto-billed. Streaming, tool loop,
and response_format supported; attachments mirror deepseek (unsupported
in the current adapter).

* fix(providers): defer Sakana structured output until after tool loop

OpenAI-compatible backends reject a request carrying both response_format
and active tools/tool_choice. Mirror the LiteLLM pattern: withhold the
JSON schema while tools are active and apply it on a final tool-free call
(tool_choice: none) for both streaming and non-streaming paths.

* fix(providers): harden Sakana tool-loop error + final-stream tool_choice

- Rethrow tool-loop failures instead of swallowing them, so a failed run
  surfaces as a ProviderError rather than a partial success (matches LiteLLM).
- Force tool_choice: 'none' on the post-tool streaming pass so the model
  cannot emit fresh tool calls that the text-only stream adapter would drop.

* fix(providers): Sakana streaming usage + filtered-tools stream guard

- Pass stream_options: { include_usage: true } on both streaming calls so
  token/cost data is captured (the shared OpenAI-compatible stream helper
  only fills usage from chunk usage, which the API omits without the flag).
- Include !hasActiveTools in the early-stream guard so requests whose tools
  are all filtered out (e.g. usageControl 'none') still take the fast
  streaming path instead of the tool-loop path. Mirrors LiteLLM.

* fix(providers): answer every Sakana tool_call to keep message history valid

An assistant message lists all tool_calls, so a call for an unconfigured
tool must still get a matching `tool` response or the next request violates
the OpenAI message contract. Emit an error tool-result for unknown tools
instead of dropping them.

* test(session): de-flake SessionProvider normal-load test

flush() only drained microtasks, so the query->render update occasionally
lost the race and ctx.data was still null after the flush budget. Yield one
macrotask tick per flush so React Query's notifyManager and deferred renders
settle deterministically. Verified across repeated local runs.

Author: waleedlatif1

apps/sim/app/_shell/providers/session-provider.test.tsx

@@ -107,12 +107,18 @@ function renderProvider(): Harness {
   }
 }
 
-/** Flush pending microtasks inside an act() boundary. */
+/**
+ * Flush pending work inside an act() boundary. Drains the microtask queue and
+ * then yields one macrotask tick, so React Query's notifyManager (which can
+ * schedule observer notifications on a timer) and any deferred renders settle
+ * deterministically — microtask-only flushing raced the query→render update.
+ */
 async function flush() {
   await act(async () => {
     await Promise.resolve()
     await Promise.resolve()
     await Promise.resolve()
+    await new Promise<void>((resolve) => setTimeout(resolve, 0))
   })
 }
 

apps/sim/components/icons.tsx

@@ -3439,6 +3439,16 @@ export const DeepseekIcon = (props: SVGProps<SVGSVGElement>) => (
   </svg>
 )
 
+export const SakanaIcon = (props: SVGProps<SVGSVGElement>) => (
+  <svg {...props} height='1em' viewBox='152 5 38 30' width='1em' xmlns='http://www.w3.org/2000/svg'>
+    <title>Sakana AI</title>
+    <path
+      d='m187.2 7.8-2.5-0.7c-6.3-1.8-12.7-1.2-18 1.5l-10.2 5.7c-1.2 0.7-0.2 2.5 1 1.8l7.6-4.4c0.8 1.7 1.5 4 1.1 7.7-1.4-0.3-6-1.4-10.9 1.5-0.6 0.3-0.8 1.1-0.3 1.7 0.5 0.5 1.2 0.3 1.3 0.2 2.2-1.3 5.6-2.4 9.6-1.4-0.7 2.5-2.5 5.6-6 7.8-1.5 0.7-0.4 2.3 0.7 1.8 1.8-1 5.3-3.4 6.9-9 2.1 0.9 4.2 2.4 5.9 4.6l-7.2 4.1c-1.2 0.6-0.3 2.4 1.1 1.7l9-5c4.6-2.7 8.3-7.5 10.1-13.1l1.3-5.3c0.4-0.4 0-1.1-0.5-1.2zm-11.5 17.5-0.6 0.4c-2-2.6-4.5-4.7-7.5-5.7 0.5-3.8-0.3-6.8-1.2-9.1l1.1-0.6c4.8-2 9.8-2.7 16.2-0.9l1.6 0.4-0.8 2.7c-1.5 4.9-4.5 9.6-8.8 12.8z'
+      fill='#E60000'
+    />
+  </svg>
+)
+
 export function GeminiIcon(props: SVGProps<SVGSVGElement>) {
   const id = useId()
   const gradientId = `gemini_gradient_${id}`

apps/sim/lib/tokenization/constants.ts

@@ -56,6 +56,11 @@ export const TOKENIZATION_CONFIG = {
       confidence: 'medium',
       supportedMethods: ['heuristic', 'fallback'],
     },
+    sakana: {
+      avgCharsPerToken: 4,
+      confidence: 'medium',
+      supportedMethods: ['heuristic', 'fallback'],
+    },
     ollama: {
       avgCharsPerToken: 4,
       confidence: 'low',

apps/sim/providers/attachments.ts

@@ -35,6 +35,7 @@ export type AttachmentProvider =
   | 'xai'
   | 'deepseek'
   | 'cerebras'
+  | 'sakana'
 
 export interface PreparedProviderAttachment {
   file: UserFile
@@ -118,7 +119,7 @@ const BEDROCK_DOCUMENT_FORMATS = new Set([
 const BEDROCK_IMAGE_FORMATS = new Set(['png', 'jpeg', 'jpg', 'gif', 'webp'])
 const BEDROCK_VIDEO_FORMATS = new Set(['mp4', 'mov', 'mkv', 'webm'])
 
-const UNSUPPORTED_FILE_PROVIDERS = new Set<AttachmentProvider>(['deepseek', 'cerebras'])
+const UNSUPPORTED_FILE_PROVIDERS = new Set<AttachmentProvider>(['deepseek', 'cerebras', 'sakana'])
 
 const PROVIDER_SUPPORTED_LABELS: Record<AttachmentProvider, string> = {
   openai: 'images and documents through the Responses API input_image/input_file parts',
@@ -137,6 +138,7 @@ const PROVIDER_SUPPORTED_LABELS: Record<AttachmentProvider, string> = {
   xai: 'images through image_url message parts on Grok vision models',
   deepseek: 'no file attachments in the current API adapter',
   cerebras: 'no file attachments in the current API adapter',
+  sakana: 'no file attachments in the current API adapter',
 }
 
 export function getAttachmentProvider(providerId: ProviderId | string): AttachmentProvider | null {
@@ -156,6 +158,7 @@ export function getAttachmentProvider(providerId: ProviderId | string): Attachme
   if (providerId === 'xai') return 'xai'
   if (providerId === 'deepseek') return 'deepseek'
   if (providerId === 'cerebras') return 'cerebras'
+  if (providerId === 'sakana') return 'sakana'
   return null
 }
 
@@ -303,6 +306,7 @@ function isMimeTypeSupportedByProvider(
       return isImageMimeType(mimeType)
     case 'deepseek':
     case 'cerebras':
+    case 'sakana':
       return false
     default: {
       const _exhaustive: never = provider

apps/sim/providers/models.test.ts

@@ -102,3 +102,35 @@ describe('orderModelIdsByReleaseDate', () => {
     expect([...ordered].sort()).toEqual([...input].sort())
   })
 })
+
+describe('sakana provider definition', () => {
+  const sakana = PROVIDER_DEFINITIONS.sakana
+
+  it('is registered with fugu as the default model', () => {
+    expect(sakana).toBeDefined()
+    expect(sakana.id).toBe('sakana')
+    expect(sakana.defaultModel).toBe('fugu')
+    expect(sakana.modelPatterns).toEqual([/^fugu/])
+  })
+
+  it('exposes fugu and fugu-ultra with a 1M context window', () => {
+    expect(sakana.models.map((m) => m.id)).toEqual(['fugu', 'fugu-ultra'])
+    for (const model of sakana.models) {
+      expect(model.contextWindow).toBe(1000000)
+    }
+  })
+
+  it('prices both models at the documented fugu-ultra ceiling', () => {
+    for (const model of sakana.models) {
+      expect(model.pricing.input).toBe(5)
+      expect(model.pricing.output).toBe(30)
+      expect(model.pricing.cachedInput).toBe(0.5)
+    }
+  })
+
+  it('routes bare fugu model IDs to the sakana provider', () => {
+    const baseModels = getBaseModelProviders()
+    expect(baseModels.fugu).toBe('sakana')
+    expect(baseModels['fugu-ultra']).toBe('sakana')
+  })
+})

apps/sim/providers/models.ts

@@ -23,6 +23,7 @@ import {
   OllamaIcon,
   OpenAIIcon,
   OpenRouterIcon,
+  SakanaIcon,
   TogetherIcon,
   VertexIcon,
   VllmIcon,
@@ -2197,6 +2198,47 @@ export const PROVIDER_DEFINITIONS: Record<string, ProviderDefinition> = {
       },
     ],
   },
+  sakana: {
+    id: 'sakana',
+    name: 'Sakana AI',
+    description: "Sakana AI's Fugu multi-agent models via an OpenAI-compatible API",
+    defaultModel: 'fugu',
+    modelPatterns: [/^fugu/],
+    icon: SakanaIcon,
+    color: '#E60000',
+    capabilities: {
+      temperature: { min: 0, max: 2 },
+      toolUsageControl: true,
+    },
+    models: [
+      {
+        id: 'fugu',
+        pricing: {
+          input: 5,
+          cachedInput: 0.5,
+          output: 30,
+          updatedAt: '2026-06-22',
+        },
+        capabilities: {},
+        contextWindow: 1000000,
+        releaseDate: '2026-06-15',
+        speedOptimized: true,
+      },
+      {
+        id: 'fugu-ultra',
+        pricing: {
+          input: 5,
+          cachedInput: 0.5,
+          output: 30,
+          updatedAt: '2026-06-22',
+        },
+        capabilities: {},
+        contextWindow: 1000000,
+        releaseDate: '2026-06-15',
+        recommended: true,
+      },
+    ],
+  },
   mistral: {
     id: 'mistral',
     name: 'Mistral AI',

apps/sim/providers/registry.ts

@@ -16,6 +16,7 @@ import { ollamaProvider } from '@/providers/ollama'
 import { ollamaCloudProvider } from '@/providers/ollama-cloud'
 import { openaiProvider } from '@/providers/openai'
 import { openRouterProvider } from '@/providers/openrouter'
+import { sakanaProvider } from '@/providers/sakana'
 import { togetherProvider } from '@/providers/together'
 import type { ProviderConfig, ProviderId } from '@/providers/types'
 import { vertexProvider } from '@/providers/vertex'
@@ -34,6 +35,7 @@ const providerRegistry: Record<ProviderId, ProviderConfig> = {
   xai: xAIProvider,
   cerebras: cerebrasProvider,
   groq: groqProvider,
+  sakana: sakanaProvider,
   vllm: vllmProvider,
   litellm: litellmProvider,
   mistral: mistralProvider,