diff --git a/.changeset/add-fireworks-provider.md b/.changeset/add-fireworks-provider.md
new file mode 100644
index 00000000..b33094f6
--- /dev/null
+++ b/.changeset/add-fireworks-provider.md
@@ -0,0 +1,8 @@
+---
+"@perstack/core": patch
+"@perstack/runtime": patch
+"@perstack/fireworks-provider": patch
+"perstack": patch
+---
+
+feat: add Fireworks AI provider
diff --git a/.github/workflows/e2e.yml b/.github/workflows/e2e.yml
index 43c61b9b..a531ef6f 100644
--- a/.github/workflows/e2e.yml
+++ b/.github/workflows/e2e.yml
@@ -79,6 +79,7 @@ jobs:
           EXA_API_KEY: ${{ secrets.EXA_API_KEY }}
           OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
           GOOGLE_GENERATIVE_AI_API_KEY: ${{ secrets.GOOGLE_GENERATIVE_AI_API_KEY }}
+          FIREWORKS_API_KEY: ${{ secrets.FIREWORKS_API_KEY }}
           PERSTACK_API_KEY: ${{ secrets.PERSTACK_STAGING_API_KEY }}
 
   # Gate job for branch protection: required check that passes when E2E is
diff --git a/bun.lock b/bun.lock
index 9796aab9..b8dcd629 100644
--- a/bun.lock
+++ b/bun.lock
@@ -18,10 +18,10 @@
     },
     "apps/base": {
       "name": "@perstack/base",
-      "version": "0.0.70",
+      "version": "0.0.73",
       "dependencies": {
         "@modelcontextprotocol/sdk": "^1.26.0",
-        "@perstack/core": "0.0.58",
+        "@perstack/core": "0.0.60",
         "commander": "^14.0.3",
         "zod": "^4.3.6",
       },
@@ -49,7 +49,7 @@
     },
     "apps/perstack": {
       "name": "perstack",
-      "version": "0.0.100",
+      "version": "0.0.111",
       "dependencies": {
         "commander": "^14.0.3",
       },
@@ -67,7 +67,7 @@
     },
     "packages/core": {
       "name": "@perstack/core",
-      "version": "0.0.58",
+      "version": "0.0.60",
       "dependencies": {
         "@paralleldrive/cuid2": "^3.3.0",
         "zod": "^4.3.6",
@@ -80,7 +80,7 @@
     },
     "packages/filesystem": {
       "name": "@perstack/filesystem-storage",
-      "version": "0.0.29",
+      "version": "0.0.31",
       "dependencies": {
         "@perstack/core": "workspace:*",
       },
@@ -93,7 +93,7 @@
     },
     "packages/installer": {
       "name": "@perstack/installer",
-      "version": "0.0.23",
+      "version": "0.0.29",
       "dependencies": {
         "@perstack/api-client": "^0.0.57",
         "@perstack/core": "workspace:*",
@@ -109,7 +109,7 @@
     },
     "packages/log": {
       "name": "@perstack/log",
-      "version": "0.0.15",
+      "version": "0.0.17",
       "dependencies": {
         "@perstack/core": "workspace:*",
         "@perstack/filesystem-storage": "workspace:*",
@@ -122,7 +122,7 @@
     },
     "packages/perstack-toml": {
       "name": "@perstack/perstack-toml",
-      "version": "0.0.14",
+      "version": "0.0.17",
       "dependencies": {
         "@perstack/core": "workspace:*",
         "smol-toml": "^1.6.0",
@@ -136,7 +136,7 @@
     },
     "packages/providers/anthropic": {
       "name": "@perstack/anthropic-provider",
-      "version": "0.0.32",
+      "version": "0.0.34",
       "dependencies": {
         "@ai-sdk/anthropic": "^3.0.47",
         "@perstack/core": "workspace:*",
@@ -151,7 +151,7 @@
     },
     "packages/providers/azure-openai": {
       "name": "@perstack/azure-openai-provider",
-      "version": "0.0.31",
+      "version": "0.0.33",
       "dependencies": {
         "@ai-sdk/azure": "^3.0.31",
         "@perstack/core": "workspace:*",
@@ -166,7 +166,7 @@
     },
     "packages/providers/bedrock": {
       "name": "@perstack/bedrock-provider",
-      "version": "0.0.31",
+      "version": "0.0.33",
       "dependencies": {
         "@ai-sdk/amazon-bedrock": "^4.0.60",
         "@perstack/core": "workspace:*",
@@ -181,7 +181,7 @@
     },
     "packages/providers/core": {
       "name": "@perstack/provider-core",
-      "version": "0.0.31",
+      "version": "0.0.33",
       "dependencies": {
         "@perstack/core": "workspace:*",
         "undici": "^7.22.0",
@@ -195,7 +195,7 @@
     },
     "packages/providers/deepseek": {
       "name": "@perstack/deepseek-provider",
-      "version": "0.0.31",
+      "version": "0.0.33",
       "dependencies": {
         "@ai-sdk/deepseek": "^2.0.20",
         "@perstack/core": "workspace:*",
@@ -208,9 +208,24 @@
         "typescript": "^5.9.3",
       },
     },
+    "packages/providers/fireworks": {
+      "name": "@perstack/fireworks-provider",
+      "version": "0.0.1",
+      "dependencies": {
+        "@ai-sdk/fireworks": "^2.0.36",
+        "@perstack/core": "workspace:*",
+        "@perstack/provider-core": "workspace:*",
+      },
+      "devDependencies": {
+        "@tsconfig/node22": "^22.0.5",
+        "@types/node": "^25.3.0",
+        "ai": "^6.0.86",
+        "typescript": "^5.9.3",
+      },
+    },
     "packages/providers/google": {
       "name": "@perstack/google-provider",
-      "version": "0.0.31",
+      "version": "0.0.33",
       "dependencies": {
         "@ai-sdk/google": "^3.0.29",
         "@perstack/core": "workspace:*",
@@ -225,7 +240,7 @@
     },
     "packages/providers/ollama": {
       "name": "@perstack/ollama-provider",
-      "version": "0.0.31",
+      "version": "0.0.33",
       "dependencies": {
         "@perstack/core": "workspace:*",
         "@perstack/provider-core": "workspace:*",
@@ -240,7 +255,7 @@
     },
     "packages/providers/openai": {
       "name": "@perstack/openai-provider",
-      "version": "0.0.31",
+      "version": "0.0.33",
       "dependencies": {
         "@ai-sdk/openai": "^3.0.29",
         "@perstack/core": "workspace:*",
@@ -255,7 +270,7 @@
     },
     "packages/providers/vertex": {
       "name": "@perstack/vertex-provider",
-      "version": "0.0.31",
+      "version": "0.0.33",
       "dependencies": {
         "@ai-sdk/google-vertex": "^4.0.58",
         "@perstack/core": "workspace:*",
@@ -270,7 +285,7 @@
     },
     "packages/react": {
       "name": "@perstack/react",
-      "version": "0.0.62",
+      "version": "0.0.64",
       "dependencies": {
         "@perstack/core": "0.0.58",
       },
@@ -289,20 +304,21 @@
     },
     "packages/runtime": {
       "name": "@perstack/runtime",
-      "version": "0.0.121",
+      "version": "0.0.126",
       "dependencies": {
         "@ai-sdk/amazon-bedrock": "^4.0.60",
         "@ai-sdk/anthropic": "^3.0.44",
         "@ai-sdk/azure": "^3.0.31",
         "@ai-sdk/deepseek": "^2.0.20",
+        "@ai-sdk/fireworks": "^2.0.36",
         "@ai-sdk/google": "^3.0.29",
         "@ai-sdk/google-vertex": "^4.0.58",
         "@ai-sdk/openai": "^3.0.29",
         "@modelcontextprotocol/sdk": "^1.26.0",
         "@paralleldrive/cuid2": "^3.3.0",
         "@perstack/api-client": "^0.0.57",
-        "@perstack/base": "0.0.70",
-        "@perstack/core": "0.0.58",
+        "@perstack/base": "0.0.73",
+        "@perstack/core": "0.0.60",
         "ai": "^6.0.86",
         "ollama-ai-provider-v2": "^3.3.0",
         "smol-toml": "^1.6.0",
@@ -315,6 +331,7 @@
         "@perstack/azure-openai-provider": "workspace:*",
         "@perstack/bedrock-provider": "workspace:*",
         "@perstack/deepseek-provider": "workspace:*",
+        "@perstack/fireworks-provider": "workspace:*",
         "@perstack/google-provider": "workspace:*",
         "@perstack/ollama-provider": "workspace:*",
         "@perstack/openai-provider": "workspace:*",
@@ -328,7 +345,7 @@
     },
     "packages/skill-manager": {
       "name": "@perstack/skill-manager",
-      "version": "0.0.16",
+      "version": "0.0.20",
       "dependencies": {
         "@modelcontextprotocol/sdk": "^1.26.0",
         "@paralleldrive/cuid2": "^3.3.0",
@@ -344,7 +361,7 @@
     },
     "packages/studio": {
       "name": "@perstack/studio",
-      "version": "0.0.2",
+      "version": "0.0.10",
       "dependencies": {
         "@perstack/api-client": "^0.0.57",
         "@perstack/core": "workspace:*",
@@ -359,7 +376,7 @@
     },
     "packages/tui": {
       "name": "@perstack/tui",
-      "version": "0.0.20",
+      "version": "0.0.23",
       "dependencies": {
         "@paralleldrive/cuid2": "^3.3.0",
         "@perstack/core": "workspace:*",
@@ -376,7 +393,7 @@
     },
     "packages/tui-components": {
       "name": "@perstack/tui-components",
-      "version": "0.0.22",
+      "version": "0.0.25",
       "dependencies": {
         "@perstack/core": "workspace:*",
         "@perstack/react": "workspace:*",
@@ -400,6 +417,8 @@
 
     "@ai-sdk/deepseek": ["@ai-sdk/deepseek@2.0.20", "", { "dependencies": { "@ai-sdk/provider": "3.0.8", "@ai-sdk/provider-utils": "4.0.15" }, "peerDependencies": { "zod": "^3.25.76 || ^4.1.8" } }, "sha512-MAL04sDTOWUiBjAGWaVgyeE4bYRb9QpKYRlIeCTZFga6I8yQs50XakhWEssrmvVihdpHGkqpDtCHsFqCydsWLA=="],
 
+    "@ai-sdk/fireworks": ["@ai-sdk/fireworks@2.0.36", "", { "dependencies": { "@ai-sdk/openai-compatible": "2.0.31", "@ai-sdk/provider": "3.0.8", "@ai-sdk/provider-utils": "4.0.16" }, "peerDependencies": { "zod": "^3.25.76 || ^4.1.8" } }, "sha512-hSZUcC25H+c3lcNrJWt9jCvmnzUidgysukVzawupTDxq+CDIv9Q4mPy9QzkqUaaBDZ1w9fsz2UdUq4aev95VeA=="],
+
     "@ai-sdk/gateway": ["@ai-sdk/gateway@3.0.53", "", { "dependencies": { "@ai-sdk/provider": "3.0.8", "@ai-sdk/provider-utils": "4.0.15", "@vercel/oidc": "3.1.0" }, "peerDependencies": { "zod": "^3.25.76 || ^4.1.8" } }, "sha512-QT3FEoNARMRlk8JJVR7L98exiK9C8AGfrEJVbRxBT1yIXKs/N19o/+PsjTRVsARgDJNcy9JbJp1FspKucEat0Q=="],
 
     "@ai-sdk/google": ["@ai-sdk/google@3.0.30", "", { "dependencies": { "@ai-sdk/provider": "3.0.8", "@ai-sdk/provider-utils": "4.0.15" }, "peerDependencies": { "zod": "^3.25.76 || ^4.1.8" } }, "sha512-ZzG6dU0XUSSXbxQJJTQUFpWeKkfzdpR7IykEZwaiaW5d+3u3RZ/zkRiGwAOcUpLp6k0eMd+IJF4looJv21ecxw=="],
@@ -408,6 +427,8 @@
 
     "@ai-sdk/openai": ["@ai-sdk/openai@3.0.30", "", { "dependencies": { "@ai-sdk/provider": "3.0.8", "@ai-sdk/provider-utils": "4.0.15" }, "peerDependencies": { "zod": "^3.25.76 || ^4.1.8" } }, "sha512-YDht3t7TDyWKP+JYZp20VuYqSjyF2brHYh47GGFDUPf2wZiqNQ263ecL+quar2bP3GZ3BeQA8f0m2B7UwLPR+g=="],
 
+    "@ai-sdk/openai-compatible": ["@ai-sdk/openai-compatible@2.0.31", "", { "dependencies": { "@ai-sdk/provider": "3.0.8", "@ai-sdk/provider-utils": "4.0.16" }, "peerDependencies": { "zod": "^3.25.76 || ^4.1.8" } }, "sha512-e78xiImcTe2aCMQoFbVJluQmUV4XgahOmmehAuRPlcwzRv2KtkvuLCXPC9Xcy2u83e8SimVva9k9G8SvZcnaBA=="],
+
     "@ai-sdk/provider": ["@ai-sdk/provider@3.0.8", "", { "dependencies": { "json-schema": "^0.4.0" } }, "sha512-oGMAgGoQdBXbZqNG0Ze56CHjDZ1IDYOwGYxYjO5KLSlz5HiNQ9udIXsPZ61VWaHGZ5XW/jyjmr6t2xz2jGVwbQ=="],
 
     "@ai-sdk/provider-utils": ["@ai-sdk/provider-utils@4.0.15", "", { "dependencies": { "@ai-sdk/provider": "3.0.8", "@standard-schema/spec": "^1.1.0", "eventsource-parser": "^3.0.6" }, "peerDependencies": { "zod": "^3.25.76 || ^4.1.8" } }, "sha512-8XiKWbemmCbvNN0CLR9u3PQiet4gtEVIrX4zzLxnCj06AwsEDJwJVBbKrEI4t6qE8XRSIvU2irka0dcpziKW6w=="],
@@ -618,6 +639,8 @@
 
     "@perstack/filesystem-storage": ["@perstack/filesystem-storage@workspace:packages/filesystem"],
 
+    "@perstack/fireworks-provider": ["@perstack/fireworks-provider@workspace:packages/providers/fireworks"],
+
     "@perstack/google-provider": ["@perstack/google-provider@workspace:packages/providers/google"],
 
     "@perstack/installer": ["@perstack/installer@workspace:packages/installer"],
@@ -1324,8 +1347,12 @@
 
     "@ai-sdk/amazon-bedrock/@ai-sdk/anthropic": ["@ai-sdk/anthropic@3.0.46", "", { "dependencies": { "@ai-sdk/provider": "3.0.8", "@ai-sdk/provider-utils": "4.0.15" }, "peerDependencies": { "zod": "^3.25.76 || ^4.1.8" } }, "sha512-zXJPiNHaIiQ6XUqLeSYZ3ZbSzjqt1pNWEUf2hlkXlmmw8IF8KI0ruuGaDwKCExmtuNRf0E4TDxhsc9wRgWTzpw=="],
 
+    "@ai-sdk/fireworks/@ai-sdk/provider-utils": ["@ai-sdk/provider-utils@4.0.16", "", { "dependencies": { "@ai-sdk/provider": "3.0.8", "@standard-schema/spec": "^1.1.0", "eventsource-parser": "^3.0.6" }, "peerDependencies": { "zod": "^3.25.76 || ^4.1.8" } }, "sha512-kBvDqNkt5EwlzF9FujmNhhtl8FYg3e8FO8P5uneKliqfRThWemzBj+wfYr7ZCymAQhTRnwSSz1/SOqhOAwmx9g=="],
+
     "@ai-sdk/google-vertex/@ai-sdk/anthropic": ["@ai-sdk/anthropic@3.0.46", "", { "dependencies": { "@ai-sdk/provider": "3.0.8", "@ai-sdk/provider-utils": "4.0.15" }, "peerDependencies": { "zod": "^3.25.76 || ^4.1.8" } }, "sha512-zXJPiNHaIiQ6XUqLeSYZ3ZbSzjqt1pNWEUf2hlkXlmmw8IF8KI0ruuGaDwKCExmtuNRf0E4TDxhsc9wRgWTzpw=="],
 
+    "@ai-sdk/openai-compatible/@ai-sdk/provider-utils": ["@ai-sdk/provider-utils@4.0.16", "", { "dependencies": { "@ai-sdk/provider": "3.0.8", "@standard-schema/spec": "^1.1.0", "eventsource-parser": "^3.0.6" }, "peerDependencies": { "zod": "^3.25.76 || ^4.1.8" } }, "sha512-kBvDqNkt5EwlzF9FujmNhhtl8FYg3e8FO8P5uneKliqfRThWemzBj+wfYr7ZCymAQhTRnwSSz1/SOqhOAwmx9g=="],
+
     "@aws-crypto/util/@smithy/util-utf8": ["@smithy/util-utf8@2.3.0", "", { "dependencies": { "@smithy/util-buffer-from": "^2.2.0", "tslib": "^2.6.2" } }, "sha512-R8Rdn8Hy72KKcebgLiv8jQcQkXoLMOGGv5uI1/k0l+snqkOzQ1R0ChUBCxWMlBsFMekWjq0wRudIweFs7sKT5A=="],
 
     "@babel/code-frame/@babel/helper-validator-identifier": ["@babel/helper-validator-identifier@7.28.5", "", {}, "sha512-qSs4ifwzKJSV39ucNjsvc6WVHs6b7S03sOh2OcHF9UHfVPqWWALUsNUVzhSBiItjRZoLHx7nIarVjqKVusUZ1Q=="],
diff --git a/e2e/lib/prerequisites.ts b/e2e/lib/prerequisites.ts
index beb51bc0..88eea6ed 100644
--- a/e2e/lib/prerequisites.ts
+++ b/e2e/lib/prerequisites.ts
@@ -9,3 +9,7 @@ export function hasAnthropicKey(): boolean {
 export function hasGoogleKey(): boolean {
   return !!process.env.GOOGLE_GENERATIVE_AI_API_KEY
 }
+
+export function hasFireworksKey(): boolean {
+  return !!process.env.FIREWORKS_API_KEY
+}
diff --git a/e2e/perstack-cli/providers.test.ts b/e2e/perstack-cli/providers.test.ts
index e1bcdb47..bd4445b7 100644
--- a/e2e/perstack-cli/providers.test.ts
+++ b/e2e/perstack-cli/providers.test.ts
@@ -1,6 +1,11 @@
 import { describe, expect, it } from "bun:test"
 import { assertEventSequenceContains } from "../lib/assertions.js"
-import { hasAnthropicKey, hasGoogleKey, hasOpenAIKey } from "../lib/prerequisites.js"
+import {
+  hasAnthropicKey,
+  hasFireworksKey,
+  hasGoogleKey,
+  hasOpenAIKey,
+} from "../lib/prerequisites.js"
 import { runCli, withEventParsing } from "../lib/runner.js"
 
 const CONFIG = "./e2e/experts/providers.toml"
@@ -10,6 +15,7 @@ const providers = [
   { provider: "openai", hasKey: hasOpenAIKey },
   { provider: "anthropic", hasKey: hasAnthropicKey },
   { provider: "google", hasKey: hasGoogleKey },
+  { provider: "fireworks", hasKey: hasFireworksKey },
 ]
 
 describe.concurrent("LLM Providers", () => {
diff --git a/packages/core/src/known-models/index.ts b/packages/core/src/known-models/index.ts
index 8625d119..2dc5b0b0 100644
--- a/packages/core/src/known-models/index.ts
+++ b/packages/core/src/known-models/index.ts
@@ -200,6 +200,32 @@ export const knownModels = [
       },
     ],
   },
+  {
+    provider: "fireworks",
+    models: [
+      // https://fireworks.ai/models/fireworks/kimi-k2p5
+      {
+        name: "accounts/fireworks/models/kimi-k2p5",
+        tier: "high" as const,
+        contextWindow: 262_144,
+        maxOutputTokens: 262_144,
+      },
+      // https://fireworks.ai/models/fireworks/deepseek-v3p2
+      {
+        name: "accounts/fireworks/models/deepseek-v3p2",
+        tier: "high" as const,
+        contextWindow: 163_840,
+        maxOutputTokens: 163_840,
+      },
+      // https://fireworks.ai/models/fireworks/glm-5
+      {
+        name: "accounts/fireworks/models/glm-5",
+        tier: "high" as const,
+        contextWindow: 202_752,
+        maxOutputTokens: 202_752,
+      },
+    ],
+  },
   {
     provider: "ollama",
     models: [
diff --git a/packages/core/src/known-models/model-tiers.test.ts b/packages/core/src/known-models/model-tiers.test.ts
index e5481e53..d404f75d 100644
--- a/packages/core/src/known-models/model-tiers.test.ts
+++ b/packages/core/src/known-models/model-tiers.test.ts
@@ -1,6 +1,6 @@
 import { describe, expect, it } from "bun:test"
 import { knownModels } from "./index.js"
-import { modelTierSchema, resolveModelTier } from "./model-tiers.js"
+import { modelTierSchema, resolveModelTier, resolveModelTierWithFallback } from "./model-tiers.js"
 
 describe("@perstack/core: modelTierSchema", () => {
   it("accepts valid tier values", () => {
@@ -61,6 +61,12 @@ describe("@perstack/core: resolveModelTier", () => {
     expect(resolveModelTier("deepseek", "low")).toBeUndefined()
   })
 
+  it("resolves fireworks tiers", () => {
+    expect(resolveModelTier("fireworks", "high")).toBe("accounts/fireworks/models/kimi-k2p5")
+    expect(resolveModelTier("fireworks", "middle")).toBeUndefined()
+    expect(resolveModelTier("fireworks", "low")).toBeUndefined()
+  })
+
   it("every model in knownModels has a valid tier", () => {
     const validTiers = new Set(["low", "middle", "high"])
     for (const provider of knownModels) {
@@ -70,3 +76,18 @@ describe("@perstack/core: resolveModelTier", () => {
     }
   })
 })
+
+describe("@perstack/core: resolveModelTierWithFallback", () => {
+  it("returns high tier model for providers with all tiers", () => {
+    expect(resolveModelTierWithFallback("anthropic")).toBe("claude-opus-4-6")
+  })
+
+  it("returns high tier model for provider with only high tier", () => {
+    expect(resolveModelTierWithFallback("fireworks")).toBe("accounts/fireworks/models/kimi-k2p5")
+  })
+
+  it("cascades from high to middle when high is missing", () => {
+    // deepseek has no "low" but has "middle" and "high"
+    expect(resolveModelTierWithFallback("deepseek")).toBe("deepseek-reasoner")
+  })
+})
diff --git a/packages/core/src/known-models/model-tiers.ts b/packages/core/src/known-models/model-tiers.ts
index 24a64e24..e6854e6a 100644
--- a/packages/core/src/known-models/model-tiers.ts
+++ b/packages/core/src/known-models/model-tiers.ts
@@ -28,3 +28,17 @@ export function resolveModelTier(providerName: ProviderName, tier: ModelTier): s
   const providerModels = knownModels.find((p) => p.provider === lookupProvider)
   return providerModels?.models.find((m) => m.tier === tier)?.name
 }
+
+const TIER_CASCADE: ModelTier[] = ["high", "middle", "low"]
+
+/**
+ * Resolve a model by cascading through tiers from high to low.
+ * Used as the final fallback when no explicit model or tier-specific match is found.
+ */
+export function resolveModelTierWithFallback(providerName: ProviderName): string | undefined {
+  for (const tier of TIER_CASCADE) {
+    const model = resolveModelTier(providerName, tier)
+    if (model) return model
+  }
+  return undefined
+}
diff --git a/packages/core/src/schemas/provider-config.ts b/packages/core/src/schemas/provider-config.ts
index 35b05673..317cf17c 100644
--- a/packages/core/src/schemas/provider-config.ts
+++ b/packages/core/src/schemas/provider-config.ts
@@ -15,6 +15,7 @@ export type ProviderName =
   | "amazon-bedrock"
   | "google-vertex"
   | "deepseek"
+  | "fireworks"
 
 export const providerNameSchema = z.enum([
   "anthropic",
@@ -25,6 +26,7 @@ export const providerNameSchema = z.enum([
   "amazon-bedrock",
   "google-vertex",
   "deepseek",
+  "fireworks",
 ])
 
 /** Anthropic provider configuration */
@@ -200,6 +202,25 @@ export const deepseekProviderConfigSchema = z.object({
 })
 deepseekProviderConfigSchema satisfies z.ZodType<DeepseekProviderConfig>
 
+/** Fireworks AI provider configuration */
+export interface FireworksProviderConfig {
+  providerName: "fireworks"
+  /** API key for Fireworks AI */
+  apiKey: string
+  /** Custom base URL */
+  baseUrl?: string
+  /** Custom headers */
+  headers?: Headers
+}
+
+export const fireworksProviderConfigSchema = z.object({
+  providerName: z.literal(providerNameSchema.enum.fireworks),
+  apiKey: z.string(),
+  baseUrl: z.string().optional(),
+  headers: headersSchema,
+})
+fireworksProviderConfigSchema satisfies z.ZodType<FireworksProviderConfig>
+
 /** Union of all provider configurations */
 export type ProviderConfig =
   | AnthropicProviderConfig
@@ -210,6 +231,7 @@ export type ProviderConfig =
   | AmazonBedrockProviderConfig
   | GoogleVertexProviderConfig
   | DeepseekProviderConfig
+  | FireworksProviderConfig
 
 export const providerConfigSchema = z.discriminatedUnion("providerName", [
   anthropicProviderConfigSchema,
@@ -220,4 +242,5 @@ export const providerConfigSchema = z.discriminatedUnion("providerName", [
   amazonBedrockProviderConfigSchema,
   googleVertexProviderConfigSchema,
   deepseekProviderConfigSchema,
+  fireworksProviderConfigSchema,
 ])
diff --git a/packages/providers/fireworks/package.json b/packages/providers/fireworks/package.json
new file mode 100644
index 00000000..a778fb84
--- /dev/null
+++ b/packages/providers/fireworks/package.json
@@ -0,0 +1,43 @@
+{
+  "name": "@perstack/fireworks-provider",
+  "private": true,
+  "version": "0.0.1",
+  "description": "Fireworks AI provider adapter for Perstack",
+  "author": "Wintermute Technologies, Inc.",
+  "license": "Apache-2.0",
+  "type": "module",
+  "exports": {
+    ".": "./src/index.ts"
+  },
+  "publishConfig": {
+    "exports": {
+      ".": {
+        "types": "./dist/src/index.d.ts",
+        "import": "./dist/src/index.js"
+      }
+    }
+  },
+  "files": [
+    "dist"
+  ],
+  "scripts": {
+    "clean": "rm -rf dist",
+    "build": "bun run clean && tsdown --config ../../../tsdown.config.ts",
+    "typecheck": "tsc --noEmit",
+    "test": "bun test"
+  },
+  "dependencies": {
+    "@ai-sdk/fireworks": "^2.0.36",
+    "@perstack/core": "workspace:*",
+    "@perstack/provider-core": "workspace:*"
+  },
+  "devDependencies": {
+    "@tsconfig/node22": "^22.0.5",
+    "@types/node": "^25.3.0",
+    "ai": "^6.0.86",
+    "typescript": "^5.9.3"
+  },
+  "engines": {
+    "bun": ">=1.2.0"
+  }
+}
diff --git a/packages/providers/fireworks/src/adapter.test.ts b/packages/providers/fireworks/src/adapter.test.ts
new file mode 100644
index 00000000..4ec9f591
--- /dev/null
+++ b/packages/providers/fireworks/src/adapter.test.ts
@@ -0,0 +1,33 @@
+import { describe, expect, it } from "bun:test"
+import type { FireworksProviderConfig } from "@perstack/core"
+import { FireworksProviderAdapter } from "./adapter.js"
+
+const mockConfig: FireworksProviderConfig = {
+  providerName: "fireworks",
+  apiKey: "test-api-key",
+}
+
+describe("FireworksProviderAdapter", () => {
+  describe("providerName", () => {
+    it("returns fireworks", () => {
+      const adapter = new FireworksProviderAdapter(mockConfig)
+      expect(adapter.providerName).toBe("fireworks")
+    })
+  })
+
+  describe("createModel", () => {
+    it("creates a language model", () => {
+      const adapter = new FireworksProviderAdapter(mockConfig)
+      const model = adapter.createModel("accounts/fireworks/models/firefunction-v1")
+      expect(model).toBeDefined()
+    })
+  })
+
+  describe("getProviderTools", () => {
+    it("returns empty object for any tool names (no tools supported)", () => {
+      const adapter = new FireworksProviderAdapter(mockConfig)
+      const tools = adapter.getProviderTools(["webSearch"])
+      expect(tools).toEqual({})
+    })
+  })
+})
diff --git a/packages/providers/fireworks/src/adapter.ts b/packages/providers/fireworks/src/adapter.ts
new file mode 100644
index 00000000..8a200b4c
--- /dev/null
+++ b/packages/providers/fireworks/src/adapter.ts
@@ -0,0 +1,39 @@
+import { createFireworks } from "@ai-sdk/fireworks"
+import type { FireworksProviderConfig } from "@perstack/core"
+import {
+  BaseProviderAdapter,
+  type ProviderAdapterOptions,
+  type ProviderError,
+} from "@perstack/provider-core"
+import type { LanguageModel } from "ai"
+import { isFireworksRetryable, normalizeFireworksError } from "./errors.js"
+
+export class FireworksProviderAdapter extends BaseProviderAdapter {
+  readonly providerName = "fireworks" as const
+  private readonly client: ReturnType<typeof createFireworks>
+
+  constructor(
+    readonly config: FireworksProviderConfig,
+    options?: ProviderAdapterOptions,
+  ) {
+    super(options)
+    this.client = createFireworks({
+      apiKey: config.apiKey,
+      baseURL: config.baseUrl,
+      headers: config.headers,
+      fetch: options?.proxyUrl ? this.createProxyFetch(options.proxyUrl) : undefined,
+    })
+  }
+
+  override createModel(modelId: string): LanguageModel {
+    return this.client(modelId)
+  }
+
+  override normalizeError(error: unknown): ProviderError {
+    return normalizeFireworksError(error)
+  }
+
+  override isRetryable(error: unknown): boolean {
+    return isFireworksRetryable(error)
+  }
+}
diff --git a/packages/providers/fireworks/src/errors.ts b/packages/providers/fireworks/src/errors.ts
new file mode 100644
index 00000000..dcfdf55b
--- /dev/null
+++ b/packages/providers/fireworks/src/errors.ts
@@ -0,0 +1,50 @@
+import type { ProviderError } from "@perstack/provider-core"
+import { APICallError } from "ai"
+
+export function normalizeFireworksError(error: unknown): ProviderError {
+  if (error instanceof APICallError) {
+    return {
+      name: error.name,
+      message: error.message,
+      statusCode: error.statusCode,
+      isRetryable: isFireworksRetryable(error),
+      provider: "fireworks",
+      originalError: error,
+    }
+  }
+  if (error instanceof Error) {
+    return {
+      name: error.name,
+      message: error.message,
+      isRetryable: isFireworksRetryable(error),
+      provider: "fireworks",
+      originalError: error,
+    }
+  }
+  return {
+    name: "UnknownError",
+    message: String(error),
+    isRetryable: false,
+    provider: "fireworks",
+    originalError: error,
+  }
+}
+
+export function isFireworksRetryable(error: unknown): boolean {
+  if (error instanceof APICallError) {
+    if (error.isRetryable) return true
+    const statusCode = error.statusCode
+    if (statusCode === 429) return true
+    if (statusCode === 500) return true
+    if (statusCode === 502) return true
+    if (statusCode === 503) return true
+    if (statusCode === 504) return true
+  }
+  if (error instanceof Error) {
+    const message = error.message.toLowerCase()
+    if (message.includes("rate limit")) return true
+    if (message.includes("timeout")) return true
+    if (message.includes("service unavailable")) return true
+  }
+  return false
+}
diff --git a/packages/providers/fireworks/src/index.ts b/packages/providers/fireworks/src/index.ts
new file mode 100644
index 00000000..e7b49b98
--- /dev/null
+++ b/packages/providers/fireworks/src/index.ts
@@ -0,0 +1 @@
+export { FireworksProviderAdapter } from "./adapter.js"
diff --git a/packages/providers/fireworks/tsconfig.json b/packages/providers/fireworks/tsconfig.json
new file mode 100644
index 00000000..563aebf5
--- /dev/null
+++ b/packages/providers/fireworks/tsconfig.json
@@ -0,0 +1,18 @@
+{
+  "extends": "@tsconfig/node22/tsconfig.json",
+  "compilerOptions": {
+    "outDir": "dist",
+    "rootDir": ".",
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true,
+    "strict": true,
+    "noUncheckedIndexedAccess": true,
+    "noImplicitOverride": true,
+    "noPropertyAccessFromIndexSignature": true,
+    "exactOptionalPropertyTypes": false,
+    "noEmit": true
+  },
+  "include": ["src/**/*.ts"],
+  "exclude": ["node_modules", "dist", "**/*.test.ts"]
+}
diff --git a/packages/runtime/package.json b/packages/runtime/package.json
index 08a73bf7..f44d81b3 100644
--- a/packages/runtime/package.json
+++ b/packages/runtime/package.json
@@ -31,6 +31,7 @@
     "@ai-sdk/anthropic": "^3.0.44",
     "@ai-sdk/azure": "^3.0.31",
     "@ai-sdk/deepseek": "^2.0.20",
+    "@ai-sdk/fireworks": "^2.0.36",
     "@ai-sdk/google": "^3.0.29",
     "@ai-sdk/google-vertex": "^4.0.58",
     "@ai-sdk/openai": "^3.0.29",
@@ -52,6 +53,7 @@
     "@perstack/azure-openai-provider": "workspace:*",
     "@perstack/bedrock-provider": "workspace:*",
     "@perstack/deepseek-provider": "workspace:*",
+    "@perstack/fireworks-provider": "workspace:*",
     "@perstack/google-provider": "workspace:*",
     "@perstack/ollama-provider": "workspace:*",
     "@perstack/openai-provider": "workspace:*",
diff --git a/packages/runtime/src/helpers/model.ts b/packages/runtime/src/helpers/model.ts
index c433590b..3e7e0b8b 100644
--- a/packages/runtime/src/helpers/model.ts
+++ b/packages/runtime/src/helpers/model.ts
@@ -2,6 +2,7 @@ import { createAmazonBedrock } from "@ai-sdk/amazon-bedrock"
 import { createAnthropic } from "@ai-sdk/anthropic"
 import { createAzure } from "@ai-sdk/azure"
 import { createDeepSeek } from "@ai-sdk/deepseek"
+import { createFireworks } from "@ai-sdk/fireworks"
 import { createGoogleGenerativeAI } from "@ai-sdk/google"
 import { createVertex } from "@ai-sdk/google-vertex"
 import { createOpenAI } from "@ai-sdk/openai"
@@ -114,6 +115,15 @@ export function getModel(
       })
       return deepseek(modelId)
     }
+    case "fireworks": {
+      const fireworks = createFireworks({
+        apiKey: providerConfig.apiKey,
+        baseURL: providerConfig.baseUrl,
+        headers: providerConfig.headers,
+        fetch: customFetch,
+      })
+      return fireworks(modelId)
+    }
     default: {
       const _exhaustive: never = providerConfig
       throw new Error(`Unknown provider: ${(_exhaustive as ProviderConfig).providerName}`)
diff --git a/packages/runtime/src/helpers/provider-adapter-factory.ts b/packages/runtime/src/helpers/provider-adapter-factory.ts
index 9a33948d..8a282da4 100644
--- a/packages/runtime/src/helpers/provider-adapter-factory.ts
+++ b/packages/runtime/src/helpers/provider-adapter-factory.ts
@@ -16,6 +16,7 @@ const PROVIDER_PACKAGE_NAMES: Record<ProviderName, string> = {
   "amazon-bedrock": "bedrock-provider",
   "google-vertex": "vertex-provider",
   deepseek: "deepseek-provider",
+  fireworks: "fireworks-provider",
 }
 
 // Module-level state for provider adapter factory
diff --git a/packages/runtime/src/helpers/register-providers.ts b/packages/runtime/src/helpers/register-providers.ts
index 2bede85a..43deafc2 100644
--- a/packages/runtime/src/helpers/register-providers.ts
+++ b/packages/runtime/src/helpers/register-providers.ts
@@ -3,6 +3,7 @@ import { AzureOpenAIProviderAdapter } from "@perstack/azure-openai-provider"
 import { BedrockProviderAdapter } from "@perstack/bedrock-provider"
 import type { ProviderConfig } from "@perstack/core"
 import { DeepseekProviderAdapter } from "@perstack/deepseek-provider"
+import { FireworksProviderAdapter } from "@perstack/fireworks-provider"
 import { GoogleProviderAdapter } from "@perstack/google-provider"
 import { OllamaProviderAdapter } from "@perstack/ollama-provider"
 import { OpenAIProviderAdapter } from "@perstack/openai-provider"
@@ -54,3 +55,8 @@ registerProviderAdapter(
   "deepseek",
   async () => DeepseekProviderAdapter as unknown as GenericAdapterConstructor,
 )
+
+registerProviderAdapter(
+  "fireworks",
+  async () => FireworksProviderAdapter as unknown as GenericAdapterConstructor,
+)
diff --git a/packages/runtime/src/orchestration/coordinator-executor.test.ts b/packages/runtime/src/orchestration/coordinator-executor.test.ts
index 18a29ca6..c7facd9f 100644
--- a/packages/runtime/src/orchestration/coordinator-executor.test.ts
+++ b/packages/runtime/src/orchestration/coordinator-executor.test.ts
@@ -375,7 +375,7 @@ describe("@perstack/runtime: coordinator-executor", () => {
       )
     })
 
-    it("falls back to middle tier when neither model nor expert tier exists", async () => {
+    it("falls back to high tier when neither model nor expert tier exists", async () => {
       const { executeStateMachine } = await import("../state-machine/index.js")
       mockSetupExperts.mockResolvedValueOnce({
         expertToRun: {
@@ -398,10 +398,10 @@ describe("@perstack/runtime: coordinator-executor", () => {
 
       await executor.execute(setting)
 
-      // "middle" tier for anthropic resolves to claude-sonnet-4-5
+      // Cascades high → middle → low; "high" tier for anthropic resolves to claude-opus-4-6
       expect(executeStateMachine).toHaveBeenCalledWith(
         expect.objectContaining({
-          setting: expect.objectContaining({ model: "claude-sonnet-4-5" }),
+          setting: expect.objectContaining({ model: "claude-opus-4-6" }),
         }),
       )
     })
diff --git a/packages/runtime/src/orchestration/coordinator-executor.ts b/packages/runtime/src/orchestration/coordinator-executor.ts
index 3e99ae9b..41778d50 100644
--- a/packages/runtime/src/orchestration/coordinator-executor.ts
+++ b/packages/runtime/src/orchestration/coordinator-executor.ts
@@ -9,6 +9,7 @@ import {
   type RunSetting,
   type RuntimeEvent,
   resolveModelTier,
+  resolveModelTierWithFallback,
   type Step,
 } from "@perstack/core"
 import { type SkillAdapterLifecycleEvent, SkillManager } from "@perstack/skill-manager"
@@ -61,13 +62,13 @@ export class CoordinatorExecutor {
     const { expertToRun, experts } = await setupExperts(setting, this.options.resolveExpertToRun)
     validateRuntimeVersion(experts)
 
-    // Resolve model: explicit setting > expert's default tier > middle tier fallback
+    // Resolve model: explicit setting > expert's default tier > high→middle→low fallback
     const resolvedModel =
       setting.model ??
       (expertToRun.defaultModelTier
         ? resolveModelTier(setting.providerConfig.providerName, expertToRun.defaultModelTier)
         : undefined) ??
-      resolveModelTier(setting.providerConfig.providerName, "middle")
+      resolveModelTierWithFallback(setting.providerConfig.providerName)
 
     if (!resolvedModel) {
       throw new PerstackError(
diff --git a/packages/runtime/src/orchestration/delegation-executor.ts b/packages/runtime/src/orchestration/delegation-executor.ts
index c729aa42..318d112e 100644
--- a/packages/runtime/src/orchestration/delegation-executor.ts
+++ b/packages/runtime/src/orchestration/delegation-executor.ts
@@ -13,7 +13,7 @@ import type {
   ToolResult,
   Usage,
 } from "@perstack/core"
-import { resolveModelTier } from "@perstack/core"
+import { resolveModelTier, resolveModelTierWithFallback } from "@perstack/core"
 
 /** Reference to the parent Expert that delegated */
 type DelegatedBy = NonNullable<Checkpoint["delegatedBy"]>
@@ -189,18 +189,19 @@ export class DelegationExecutor {
     const { expert, toolCallId, toolName, query } = delegation
     const delegateRunId = createId()
 
-    // Resolve per-expert model tier for the delegate expert
-    let delegateModel = parentSetting.model
+    // Resolve per-expert model tier for the delegate expert.
+    // defaultModelTier on the delegate expert is an explicit user choice and
+    // takes precedence over the parent's model.
     const delegateExpert = parentSetting.experts?.[expert.key]
+    let delegateModel: string | undefined
     if (delegateExpert?.defaultModelTier) {
-      const tierModel = resolveModelTier(
+      delegateModel = resolveModelTier(
         parentSetting.providerConfig.providerName,
         delegateExpert.defaultModelTier,
       )
-      if (tierModel) {
-        delegateModel = tierModel
-      }
     }
+    delegateModel ??=
+      parentSetting.model ?? resolveModelTierWithFallback(parentSetting.providerConfig.providerName)
 
     const delegateSetting: RunSetting = {
       ...parentSetting,
diff --git a/packages/tui/src/lib/provider-config.test.ts b/packages/tui/src/lib/provider-config.test.ts
index 66e158af..f9fe7d86 100644
--- a/packages/tui/src/lib/provider-config.test.ts
+++ b/packages/tui/src/lib/provider-config.test.ts
@@ -214,4 +214,33 @@ describe("getProviderConfig", () => {
       expect(() => getProviderConfig("deepseek", {})).toThrow("DEEPSEEK_API_KEY is not set")
     })
   })
+
+  describe("fireworks", () => {
+    it("returns fireworks config with API key", () => {
+      const env = { FIREWORKS_API_KEY: "test-key" }
+      const config = getProviderConfig("fireworks", env)
+
+      expect(config.providerName).toBe("fireworks")
+      expect((config as ConfigWithApiKey).apiKey).toBe("test-key")
+    })
+
+    it("throws when FIREWORKS_API_KEY is not set", () => {
+      expect(() => getProviderConfig("fireworks", {})).toThrow("FIREWORKS_API_KEY is not set")
+    })
+
+    it("uses baseUrl from setting if provided", () => {
+      const env = { FIREWORKS_API_KEY: "test-key" }
+      const providerTable = { setting: { baseUrl: "https://custom.api.com" } } as ProviderTable
+      const config = getProviderConfig("fireworks", env, providerTable)
+
+      expect((config as ConfigWithBaseUrl).baseUrl).toBe("https://custom.api.com")
+    })
+
+    it("uses baseUrl from env if setting not provided", () => {
+      const env = { FIREWORKS_API_KEY: "test-key", FIREWORKS_BASE_URL: "https://env.api.com" }
+      const config = getProviderConfig("fireworks", env)
+
+      expect((config as ConfigWithBaseUrl).baseUrl).toBe("https://env.api.com")
+    })
+  })
 })
diff --git a/packages/tui/src/lib/provider-config.ts b/packages/tui/src/lib/provider-config.ts
index 2a3a3c98..1b239811 100644
--- a/packages/tui/src/lib/provider-config.ts
+++ b/packages/tui/src/lib/provider-config.ts
@@ -14,6 +14,7 @@ export const PROVIDER_ENV_MAP: Record<string, string | undefined> = {
   "amazon-bedrock": "AWS_ACCESS_KEY_ID",
   "google-vertex": "GOOGLE_APPLICATION_CREDENTIALS",
   ollama: undefined,
+  fireworks: "FIREWORKS_API_KEY",
 }
 
 type SettingRecord = Record<string, unknown>
@@ -117,5 +118,15 @@ export function getProviderConfig(
         headers: setting.headers as Record<string, string> | undefined,
       }
     }
+    case "fireworks": {
+      const apiKey = env.FIREWORKS_API_KEY
+      if (!apiKey) throw new PerstackError("FIREWORKS_API_KEY is not set")
+      return {
+        providerName: "fireworks",
+        apiKey,
+        baseUrl: (setting.baseUrl as string | undefined) ?? env.FIREWORKS_BASE_URL,
+        headers: setting.headers as Record<string, string> | undefined,
+      }
+    }
   }
 }