core: add provider test coverage for upcoming refactor

Add comprehensive test suite for Provider module to ensure safe
refactoring of provider internals. Tests cover:
- Provider loading from env vars and config
- Provider filtering (disabled_providers, enabled_providers)
- Model whitelist/blacklist
- Model aliasing and custom providers
- getModel, getProvider, closest, defaultModel functions

Also adds Env module for instance-scoped environment variable access,
enabling isolated test environments without global state pollution.

4 files changed, 1805 insertions, 11 deletions

diff --git a/packages/opencode/src/env/index.ts b/packages/opencode/src/env/index.ts
new file mode 100644
index 000000000..56a8c921f
--- /dev/null
+++ b/packages/opencode/src/env/index.ts
@@ -0,0 +1,26 @@
+import { Instance } from "../project/instance"
+
+export namespace Env {
+  const state = Instance.state(() => {
+    return { ...process.env } as Record<string, string | undefined>
+  })
+
+  export function get(key: string) {
+    const env = state()
+    return env[key]
+  }
+
+  export function all() {
+    return state()
+  }
+
+  export function set(key: string, value: string) {
+    const env = state()
+    env[key] = value
+  }
+
+  export function remove(key: string) {
+    const env = state()
+    delete env[key]
+  }
+}
diff --git a/packages/opencode/src/provider/provider.ts b/packages/opencode/src/provider/provider.ts
index fef4677bc..1123e6bbe 100644
--- a/packages/opencode/src/provider/provider.ts
+++ b/packages/opencode/src/provider/provider.ts
@@ -9,6 +9,7 @@ import { Plugin } from "../plugin"
 import { ModelsDev } from "./models"
 import { NamedError } from "@opencode-ai/util/error"
 import { Auth } from "../auth"
+import { Env } from "../env"
 import { Instance } from "../project/instance"
 import { Flag } from "../flag/flag"
 import { iife } from "@/util/iife"
@@ -64,7 +65,8 @@ export namespace Provider {
     },
     async opencode(input) {
       const hasKey = await (async () => {
-        if (input.env.some((item) => process.env[item])) return true
+        const env = Env.all()
+        if (input.env.some((item) => env[item])) return true
         if (await Auth.get(input.id)) return true
         return false
       })()
@@ -128,7 +130,7 @@ export namespace Provider {
       }
     },
     "azure-cognitive-services": async () => {
-      const resourceName = process.env["AZURE_COGNITIVE_SERVICES_RESOURCE_NAME"]
+      const resourceName = Env.get("AZURE_COGNITIVE_SERVICES_RESOURCE_NAME")
       return {
         autoload: false,
         async getModel(sdk: any, modelID: string, options?: Record<string, any>) {
@@ -144,10 +146,15 @@ export namespace Provider {
       }
     },
     "amazon-bedrock": async () => {
-      if (!process.env["AWS_PROFILE"] && !process.env["AWS_ACCESS_KEY_ID"] && !process.env["AWS_BEARER_TOKEN_BEDROCK"])
-        return { autoload: false }
+      const [awsProfile, awsAccessKeyId, awsBearerToken, awsRegion] = await Promise.all([
+        Env.get("AWS_PROFILE"),
+        Env.get("AWS_ACCESS_KEY_ID"),
+        Env.get("AWS_BEARER_TOKEN_BEDROCK"),
+        Env.get("AWS_REGION"),
+      ])
+      if (!awsProfile && !awsAccessKeyId && !awsBearerToken) return { autoload: false }
 
-      const region = process.env["AWS_REGION"] ?? "us-east-1"
+      const region = awsRegion ?? "us-east-1"
 
       const { fromNodeProviderChain } = await import(await BunProc.install("@aws-sdk/credential-providers"))
       return {
@@ -246,8 +253,8 @@ export namespace Provider {
       }
     },
     "google-vertex": async () => {
-      const project = process.env["GOOGLE_CLOUD_PROJECT"] ?? process.env["GCP_PROJECT"] ?? process.env["GCLOUD_PROJECT"]
-      const location = process.env["GOOGLE_CLOUD_LOCATION"] ?? process.env["VERTEX_LOCATION"] ?? "us-east5"
+      const project = Env.get("GOOGLE_CLOUD_PROJECT") ?? Env.get("GCP_PROJECT") ?? Env.get("GCLOUD_PROJECT")
+      const location = Env.get("GOOGLE_CLOUD_LOCATION") ?? Env.get("VERTEX_LOCATION") ?? "us-east5"
       const autoload = Boolean(project)
       if (!autoload) return { autoload: false }
       return {
@@ -263,8 +270,8 @@ export namespace Provider {
       }
     },
     "google-vertex-anthropic": async () => {
-      const project = process.env["GOOGLE_CLOUD_PROJECT"] ?? process.env["GCP_PROJECT"] ?? process.env["GCLOUD_PROJECT"]
-      const location = process.env["GOOGLE_CLOUD_LOCATION"] ?? process.env["VERTEX_LOCATION"] ?? "global"
+      const project = Env.get("GOOGLE_CLOUD_PROJECT") ?? Env.get("GCP_PROJECT") ?? Env.get("GCLOUD_PROJECT")
+      const location = Env.get("GOOGLE_CLOUD_LOCATION") ?? Env.get("VERTEX_LOCATION") ?? "global"
       const autoload = Boolean(project)
       if (!autoload) return { autoload: false }
       return {
@@ -435,9 +442,10 @@ export namespace Provider {
     }
 
     // load env
+    const env = Env.all()
     for (const [providerID, provider] of Object.entries(database)) {
       if (disabled.has(providerID)) continue
-      const apiKey = provider.env.map((item) => process.env[item]).at(0)
+      const apiKey = provider.env.map((item) => env[item]).find(Boolean)
       if (!apiKey) continue
       mergeProvider(
         providerID,
diff --git a/packages/opencode/test/preload.ts b/packages/opencode/test/preload.ts
index 16fb3cd21..43d012740 100644
--- a/packages/opencode/test/preload.ts
+++ b/packages/opencode/test/preload.ts
@@ -1,4 +1,35 @@
-import { Log } from "../src/util/log"
+// IMPORTANT: Set env vars BEFORE any imports from src/ directory
+// xdg-basedir reads env vars at import time, so we must set these first
+import os from "os"
+import path from "path"
+
+const testDataDir = path.join(os.tmpdir(), "opencode-test-data-" + process.pid)
+process.env["XDG_DATA_HOME"] = testDataDir
+process.env["XDG_CACHE_HOME"] = path.join(testDataDir, "cache")
+process.env["XDG_CONFIG_HOME"] = path.join(testDataDir, "config")
+process.env["XDG_STATE_HOME"] = path.join(testDataDir, "state")
+
+// Clear provider env vars to ensure clean test state
+delete process.env["ANTHROPIC_API_KEY"]
+delete process.env["OPENAI_API_KEY"]
+delete process.env["GOOGLE_API_KEY"]
+delete process.env["GOOGLE_GENERATIVE_AI_API_KEY"]
+delete process.env["AZURE_OPENAI_API_KEY"]
+delete process.env["AWS_ACCESS_KEY_ID"]
+delete process.env["AWS_PROFILE"]
+delete process.env["OPENROUTER_API_KEY"]
+delete process.env["GROQ_API_KEY"]
+delete process.env["MISTRAL_API_KEY"]
+delete process.env["PERPLEXITY_API_KEY"]
+delete process.env["TOGETHER_API_KEY"]
+delete process.env["XAI_API_KEY"]
+delete process.env["DEEPSEEK_API_KEY"]
+delete process.env["FIREWORKS_API_KEY"]
+delete process.env["CEREBRAS_API_KEY"]
+delete process.env["SAMBANOVA_API_KEY"]
+
+// Now safe to import from src/
+const { Log } = await import("../src/util/log")
 
 Log.init({
   print: false,
diff --git a/packages/opencode/test/provider/provider.test.ts b/packages/opencode/test/provider/provider.test.ts
new file mode 100644
index 000000000..fa31d9d4f
--- /dev/null
+++ b/packages/opencode/test/provider/provider.test.ts
@@ -0,0 +1,1729 @@
+import { test, expect } from "bun:test"
+import path from "path"
+import { tmpdir } from "../fixture/fixture"
+import { Instance } from "../../src/project/instance"
+import { Provider } from "../../src/provider/provider"
+import { Env } from "../../src/env"
+
+test("provider loaded from env variable", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["anthropic"]).toBeDefined()
+      // Note: source becomes "custom" because CUSTOM_LOADERS run after env loading
+      // and anthropic has a custom loader that merges additional options
+      expect(providers["anthropic"].source).toBe("custom")
+    },
+  })
+})
+
+test("provider loaded from config with apiKey option", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              options: {
+                apiKey: "config-api-key",
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["anthropic"]).toBeDefined()
+    },
+  })
+})
+
+test("disabled_providers excludes provider", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          disabled_providers: ["anthropic"],
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["anthropic"]).toBeUndefined()
+    },
+  })
+})
+
+test("enabled_providers restricts to only listed providers", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          enabled_providers: ["anthropic"],
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+      Env.set("OPENAI_API_KEY", "test-openai-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["anthropic"]).toBeDefined()
+      expect(providers["openai"]).toBeUndefined()
+    },
+  })
+})
+
+test("model whitelist filters models for provider", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              whitelist: ["claude-sonnet-4-20250514"],
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["anthropic"]).toBeDefined()
+      const models = Object.keys(providers["anthropic"].info.models)
+      expect(models).toContain("claude-sonnet-4-20250514")
+      expect(models.length).toBe(1)
+    },
+  })
+})
+
+test("model blacklist excludes specific models", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              blacklist: ["claude-sonnet-4-20250514"],
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["anthropic"]).toBeDefined()
+      const models = Object.keys(providers["anthropic"].info.models)
+      expect(models).not.toContain("claude-sonnet-4-20250514")
+    },
+  })
+})
+
+test("custom model alias via config", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              models: {
+                "my-alias": {
+                  id: "claude-sonnet-4-20250514",
+                  name: "My Custom Alias",
+                },
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["anthropic"]).toBeDefined()
+      expect(providers["anthropic"].info.models["my-alias"]).toBeDefined()
+      expect(providers["anthropic"].info.models["my-alias"].name).toBe("My Custom Alias")
+    },
+  })
+})
+
+test("custom provider with npm package", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "custom-provider": {
+              name: "Custom Provider",
+              npm: "@ai-sdk/openai-compatible",
+              api: "https://api.custom.com/v1",
+              env: ["CUSTOM_API_KEY"],
+              models: {
+                "custom-model": {
+                  name: "Custom Model",
+                  tool_call: true,
+                  limit: {
+                    context: 128000,
+                    output: 4096,
+                  },
+                },
+              },
+              options: {
+                apiKey: "custom-key",
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["custom-provider"]).toBeDefined()
+      expect(providers["custom-provider"].info.name).toBe("Custom Provider")
+      expect(providers["custom-provider"].info.models["custom-model"]).toBeDefined()
+    },
+  })
+})
+
+test("env variable takes precedence, config merges options", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              options: {
+                timeout: 60000,
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "env-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["anthropic"]).toBeDefined()
+      // Config options should be merged
+      expect(providers["anthropic"].options.timeout).toBe(60000)
+    },
+  })
+})
+
+test("getModel returns model for valid provider/model", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const model = await Provider.getModel("anthropic", "claude-sonnet-4-20250514")
+      expect(model).toBeDefined()
+      expect(model.providerID).toBe("anthropic")
+      expect(model.modelID).toBe("claude-sonnet-4-20250514")
+      expect(model.language).toBeDefined()
+    },
+  })
+})
+
+test("getModel throws ModelNotFoundError for invalid model", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      expect(Provider.getModel("anthropic", "nonexistent-model")).rejects.toThrow()
+    },
+  })
+})
+
+test("getModel throws ModelNotFoundError for invalid provider", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      expect(Provider.getModel("nonexistent-provider", "some-model")).rejects.toThrow()
+    },
+  })
+})
+
+test("parseModel correctly parses provider/model string", () => {
+  const result = Provider.parseModel("anthropic/claude-sonnet-4")
+  expect(result.providerID).toBe("anthropic")
+  expect(result.modelID).toBe("claude-sonnet-4")
+})
+
+test("parseModel handles model IDs with slashes", () => {
+  const result = Provider.parseModel("openrouter/anthropic/claude-3-opus")
+  expect(result.providerID).toBe("openrouter")
+  expect(result.modelID).toBe("anthropic/claude-3-opus")
+})
+
+test("defaultModel returns first available model when no config set", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const model = await Provider.defaultModel()
+      expect(model.providerID).toBeDefined()
+      expect(model.modelID).toBeDefined()
+    },
+  })
+})
+
+test("defaultModel respects config model setting", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          model: "anthropic/claude-sonnet-4-20250514",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const model = await Provider.defaultModel()
+      expect(model.providerID).toBe("anthropic")
+      expect(model.modelID).toBe("claude-sonnet-4-20250514")
+    },
+  })
+})
+
+test("provider with baseURL from config", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "custom-openai": {
+              name: "Custom OpenAI",
+              npm: "@ai-sdk/openai-compatible",
+              env: [],
+              models: {
+                "gpt-4": {
+                  name: "GPT-4",
+                  tool_call: true,
+                  limit: { context: 128000, output: 4096 },
+                },
+              },
+              options: {
+                apiKey: "test-key",
+                baseURL: "https://custom.openai.com/v1",
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["custom-openai"]).toBeDefined()
+      expect(providers["custom-openai"].options.baseURL).toBe("https://custom.openai.com/v1")
+    },
+  })
+})
+
+test("model cost defaults to zero when not specified", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "test-provider": {
+              name: "Test Provider",
+              npm: "@ai-sdk/openai-compatible",
+              env: [],
+              models: {
+                "test-model": {
+                  name: "Test Model",
+                  tool_call: true,
+                  limit: { context: 128000, output: 4096 },
+                },
+              },
+              options: {
+                apiKey: "test-key",
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["test-provider"].info.models["test-model"]
+      expect(model.cost.input).toBe(0)
+      expect(model.cost.output).toBe(0)
+      expect(model.cost.cache_read).toBe(0)
+      expect(model.cost.cache_write).toBe(0)
+    },
+  })
+})
+
+test("model options are merged from existing model", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              models: {
+                "claude-sonnet-4-20250514": {
+                  options: {
+                    customOption: "custom-value",
+                  },
+                },
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["anthropic"].info.models["claude-sonnet-4-20250514"]
+      expect(model.options.customOption).toBe("custom-value")
+    },
+  })
+})
+
+test("provider removed when all models filtered out", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              whitelist: ["nonexistent-model"],
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["anthropic"]).toBeUndefined()
+    },
+  })
+})
+
+test("closest finds model by partial match", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const result = await Provider.closest("anthropic", ["sonnet-4"])
+      expect(result).toBeDefined()
+      expect(result?.providerID).toBe("anthropic")
+      expect(result?.modelID).toContain("sonnet-4")
+    },
+  })
+})
+
+test("closest returns undefined for nonexistent provider", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const result = await Provider.closest("nonexistent", ["model"])
+      expect(result).toBeUndefined()
+    },
+  })
+})
+
+test("getModel uses realIdByKey for aliased models", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              models: {
+                "my-sonnet": {
+                  id: "claude-sonnet-4-20250514",
+                  name: "My Sonnet Alias",
+                },
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["anthropic"].info.models["my-sonnet"]).toBeDefined()
+
+      const model = await Provider.getModel("anthropic", "my-sonnet")
+      expect(model).toBeDefined()
+      expect(model.modelID).toBe("my-sonnet")
+      expect(model.info.name).toBe("My Sonnet Alias")
+    },
+  })
+})
+
+test("provider api field sets default baseURL", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "custom-api": {
+              name: "Custom API",
+              npm: "@ai-sdk/openai-compatible",
+              api: "https://api.example.com/v1",
+              env: [],
+              models: {
+                "model-1": {
+                  name: "Model 1",
+                  tool_call: true,
+                  limit: { context: 8000, output: 2000 },
+                },
+              },
+              options: {
+                apiKey: "test-key",
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["custom-api"].options.baseURL).toBe("https://api.example.com/v1")
+    },
+  })
+})
+
+test("explicit baseURL overrides api field", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "custom-api": {
+              name: "Custom API",
+              npm: "@ai-sdk/openai-compatible",
+              api: "https://api.example.com/v1",
+              env: [],
+              models: {
+                "model-1": {
+                  name: "Model 1",
+                  tool_call: true,
+                  limit: { context: 8000, output: 2000 },
+                },
+              },
+              options: {
+                apiKey: "test-key",
+                baseURL: "https://custom.override.com/v1",
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["custom-api"].options.baseURL).toBe("https://custom.override.com/v1")
+    },
+  })
+})
+
+test("model inherits properties from existing database model", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              models: {
+                "claude-sonnet-4-20250514": {
+                  name: "Custom Name for Sonnet",
+                },
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["anthropic"].info.models["claude-sonnet-4-20250514"]
+      expect(model.name).toBe("Custom Name for Sonnet")
+      expect(model.tool_call).toBe(true)
+      expect(model.attachment).toBe(true)
+      expect(model.limit.context).toBeGreaterThan(0)
+    },
+  })
+})
+
+test("disabled_providers prevents loading even with env var", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          disabled_providers: ["openai"],
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("OPENAI_API_KEY", "test-openai-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["openai"]).toBeUndefined()
+    },
+  })
+})
+
+test("enabled_providers with empty array allows no providers", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          enabled_providers: [],
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+      Env.set("OPENAI_API_KEY", "test-openai-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(Object.keys(providers).length).toBe(0)
+    },
+  })
+})
+
+test("whitelist and blacklist can be combined", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              whitelist: ["claude-sonnet-4-20250514", "claude-opus-4-20250514"],
+              blacklist: ["claude-opus-4-20250514"],
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["anthropic"]).toBeDefined()
+      const models = Object.keys(providers["anthropic"].info.models)
+      expect(models).toContain("claude-sonnet-4-20250514")
+      expect(models).not.toContain("claude-opus-4-20250514")
+      expect(models.length).toBe(1)
+    },
+  })
+})
+
+test("model modalities default correctly", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "test-provider": {
+              name: "Test",
+              npm: "@ai-sdk/openai-compatible",
+              env: [],
+              models: {
+                "test-model": {
+                  name: "Test Model",
+                  tool_call: true,
+                  limit: { context: 8000, output: 2000 },
+                },
+              },
+              options: { apiKey: "test" },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["test-provider"].info.models["test-model"]
+      expect(model.modalities).toEqual({
+        input: ["text"],
+        output: ["text"],
+      })
+    },
+  })
+})
+
+test("model with custom cost values", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "test-provider": {
+              name: "Test",
+              npm: "@ai-sdk/openai-compatible",
+              env: [],
+              models: {
+                "test-model": {
+                  name: "Test Model",
+                  tool_call: true,
+                  limit: { context: 8000, output: 2000 },
+                  cost: {
+                    input: 5,
+                    output: 15,
+                    cache_read: 2.5,
+                    cache_write: 7.5,
+                  },
+                },
+              },
+              options: { apiKey: "test" },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["test-provider"].info.models["test-model"]
+      expect(model.cost.input).toBe(5)
+      expect(model.cost.output).toBe(15)
+      expect(model.cost.cache_read).toBe(2.5)
+      expect(model.cost.cache_write).toBe(7.5)
+    },
+  })
+})
+
+test("getSmallModel returns appropriate small model", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const model = await Provider.getSmallModel("anthropic")
+      expect(model).toBeDefined()
+      expect(model?.modelID).toContain("haiku")
+    },
+  })
+})
+
+test("getSmallModel respects config small_model override", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          small_model: "anthropic/claude-sonnet-4-20250514",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const model = await Provider.getSmallModel("anthropic")
+      expect(model).toBeDefined()
+      expect(model?.providerID).toBe("anthropic")
+      expect(model?.modelID).toBe("claude-sonnet-4-20250514")
+    },
+  })
+})
+
+test("provider.sort prioritizes preferred models", () => {
+  const models = [
+    { id: "random-model", name: "Random" },
+    { id: "claude-sonnet-4-latest", name: "Claude Sonnet 4" },
+    { id: "gpt-5-turbo", name: "GPT-5 Turbo" },
+    { id: "other-model", name: "Other" },
+  ] as any[]
+
+  const sorted = Provider.sort(models)
+  expect(sorted[0].id).toContain("sonnet-4")
+  expect(sorted[0].id).toContain("latest")
+  expect(sorted[sorted.length - 1].id).not.toContain("gpt-5")
+  expect(sorted[sorted.length - 1].id).not.toContain("sonnet-4")
+})
+
+test("multiple providers can be configured simultaneously", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              options: { timeout: 30000 },
+            },
+            openai: {
+              options: { timeout: 60000 },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-anthropic-key")
+      Env.set("OPENAI_API_KEY", "test-openai-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["anthropic"]).toBeDefined()
+      expect(providers["openai"]).toBeDefined()
+      expect(providers["anthropic"].options.timeout).toBe(30000)
+      expect(providers["openai"].options.timeout).toBe(60000)
+    },
+  })
+})
+
+test("provider with custom npm package", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "local-llm": {
+              name: "Local LLM",
+              npm: "@ai-sdk/openai-compatible",
+              env: [],
+              models: {
+                "llama-3": {
+                  name: "Llama 3",
+                  tool_call: true,
+                  limit: { context: 8192, output: 2048 },
+                },
+              },
+              options: {
+                apiKey: "not-needed",
+                baseURL: "http://localhost:11434/v1",
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["local-llm"]).toBeDefined()
+      expect(providers["local-llm"].info.npm).toBe("@ai-sdk/openai-compatible")
+      expect(providers["local-llm"].options.baseURL).toBe("http://localhost:11434/v1")
+    },
+  })
+})
+
+// Edge cases for model configuration
+
+test("model alias name defaults to alias key when id differs", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              models: {
+                sonnet: {
+                  id: "claude-sonnet-4-20250514",
+                  // no name specified - should default to "sonnet" (the key)
+                },
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["anthropic"].info.models["sonnet"].name).toBe("sonnet")
+    },
+  })
+})
+
+test("provider with multiple env var options only includes apiKey when single env", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "multi-env": {
+              name: "Multi Env Provider",
+              npm: "@ai-sdk/openai-compatible",
+              env: ["MULTI_ENV_KEY_1", "MULTI_ENV_KEY_2"],
+              models: {
+                "model-1": {
+                  name: "Model 1",
+                  tool_call: true,
+                  limit: { context: 8000, output: 2000 },
+                },
+              },
+              options: {
+                baseURL: "https://api.example.com/v1",
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("MULTI_ENV_KEY_1", "test-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["multi-env"]).toBeDefined()
+      // When multiple env options exist, apiKey should NOT be auto-set
+      expect(providers["multi-env"].options.apiKey).toBeUndefined()
+    },
+  })
+})
+
+test("provider with single env var includes apiKey automatically", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "single-env": {
+              name: "Single Env Provider",
+              npm: "@ai-sdk/openai-compatible",
+              env: ["SINGLE_ENV_KEY"],
+              models: {
+                "model-1": {
+                  name: "Model 1",
+                  tool_call: true,
+                  limit: { context: 8000, output: 2000 },
+                },
+              },
+              options: {
+                baseURL: "https://api.example.com/v1",
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("SINGLE_ENV_KEY", "my-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["single-env"]).toBeDefined()
+      // Single env option should auto-set apiKey
+      expect(providers["single-env"].options.apiKey).toBe("my-api-key")
+    },
+  })
+})
+
+test("model cost overrides existing cost values", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              models: {
+                "claude-sonnet-4-20250514": {
+                  cost: {
+                    input: 999,
+                    output: 888,
+                  },
+                },
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["anthropic"].info.models["claude-sonnet-4-20250514"]
+      expect(model.cost.input).toBe(999)
+      expect(model.cost.output).toBe(888)
+    },
+  })
+})
+
+test("completely new provider not in database can be configured", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "brand-new-provider": {
+              name: "Brand New",
+              npm: "@ai-sdk/openai-compatible",
+              env: [],
+              api: "https://new-api.com/v1",
+              models: {
+                "new-model": {
+                  name: "New Model",
+                  tool_call: true,
+                  reasoning: true,
+                  attachment: true,
+                  temperature: true,
+                  limit: { context: 32000, output: 8000 },
+                  modalities: {
+                    input: ["text", "image"],
+                    output: ["text"],
+                  },
+                },
+              },
+              options: {
+                apiKey: "new-key",
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["brand-new-provider"]).toBeDefined()
+      expect(providers["brand-new-provider"].info.name).toBe("Brand New")
+      const model = providers["brand-new-provider"].info.models["new-model"]
+      expect(model.reasoning).toBe(true)
+      expect(model.attachment).toBe(true)
+      expect(model.modalities?.input).toContain("image")
+    },
+  })
+})
+
+test("disabled_providers and enabled_providers interaction", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          // enabled_providers takes precedence - only these are considered
+          enabled_providers: ["anthropic", "openai"],
+          // Then disabled_providers filters from the enabled set
+          disabled_providers: ["openai"],
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-anthropic")
+      Env.set("OPENAI_API_KEY", "test-openai")
+      Env.set("GOOGLE_GENERATIVE_AI_API_KEY", "test-google")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      // anthropic: in enabled, not in disabled = allowed
+      expect(providers["anthropic"]).toBeDefined()
+      // openai: in enabled, but also in disabled = NOT allowed
+      expect(providers["openai"]).toBeUndefined()
+      // google: not in enabled = NOT allowed (even though not disabled)
+      expect(providers["google"]).toBeUndefined()
+    },
+  })
+})
+
+test("model with tool_call false", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "no-tools": {
+              name: "No Tools Provider",
+              npm: "@ai-sdk/openai-compatible",
+              env: [],
+              models: {
+                "basic-model": {
+                  name: "Basic Model",
+                  tool_call: false,
+                  limit: { context: 4000, output: 1000 },
+                },
+              },
+              options: { apiKey: "test" },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["no-tools"].info.models["basic-model"].tool_call).toBe(false)
+    },
+  })
+})
+
+test("model defaults tool_call to true when not specified", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "default-tools": {
+              name: "Default Tools Provider",
+              npm: "@ai-sdk/openai-compatible",
+              env: [],
+              models: {
+                model: {
+                  name: "Model",
+                  // tool_call not specified
+                  limit: { context: 4000, output: 1000 },
+                },
+              },
+              options: { apiKey: "test" },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["default-tools"].info.models["model"].tool_call).toBe(true)
+    },
+  })
+})
+
+test("model headers are preserved", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "headers-provider": {
+              name: "Headers Provider",
+              npm: "@ai-sdk/openai-compatible",
+              env: [],
+              models: {
+                model: {
+                  name: "Model",
+                  tool_call: true,
+                  limit: { context: 4000, output: 1000 },
+                  headers: {
+                    "X-Custom-Header": "custom-value",
+                    Authorization: "Bearer special-token",
+                  },
+                },
+              },
+              options: { apiKey: "test" },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["headers-provider"].info.models["model"]
+      expect(model.headers).toEqual({
+        "X-Custom-Header": "custom-value",
+        Authorization: "Bearer special-token",
+      })
+    },
+  })
+})
+
+test("provider env fallback - second env var used if first missing", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "fallback-env": {
+              name: "Fallback Env Provider",
+              npm: "@ai-sdk/openai-compatible",
+              env: ["PRIMARY_KEY", "FALLBACK_KEY"],
+              models: {
+                model: {
+                  name: "Model",
+                  tool_call: true,
+                  limit: { context: 4000, output: 1000 },
+                },
+              },
+              options: { baseURL: "https://api.example.com" },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      // Only set fallback, not primary
+      Env.set("FALLBACK_KEY", "fallback-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      // Provider should load because fallback env var is set
+      expect(providers["fallback-env"]).toBeDefined()
+    },
+  })
+})
+
+test("getModel returns consistent results", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const model1 = await Provider.getModel("anthropic", "claude-sonnet-4-20250514")
+      const model2 = await Provider.getModel("anthropic", "claude-sonnet-4-20250514")
+      expect(model1.providerID).toEqual(model2.providerID)
+      expect(model1.modelID).toEqual(model2.modelID)
+      expect(model1.info).toEqual(model2.info)
+    },
+  })
+})
+
+test("provider name defaults to id when not in database", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "my-custom-id": {
+              // no name specified
+              npm: "@ai-sdk/openai-compatible",
+              env: [],
+              models: {
+                model: {
+                  name: "Model",
+                  tool_call: true,
+                  limit: { context: 4000, output: 1000 },
+                },
+              },
+              options: { apiKey: "test" },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["my-custom-id"].info.name).toBe("my-custom-id")
+    },
+  })
+})
+
+test("ModelNotFoundError includes suggestions for typos", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      try {
+        await Provider.getModel("anthropic", "claude-sonet-4") // typo: sonet instead of sonnet
+        expect(true).toBe(false) // Should not reach here
+      } catch (e: any) {
+        expect(e.data.suggestions).toBeDefined()
+        expect(e.data.suggestions.length).toBeGreaterThan(0)
+      }
+    },
+  })
+})
+
+test("ModelNotFoundError for provider includes suggestions", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      try {
+        await Provider.getModel("antropic", "claude-sonnet-4") // typo: antropic
+        expect(true).toBe(false) // Should not reach here
+      } catch (e: any) {
+        expect(e.data.suggestions).toBeDefined()
+        expect(e.data.suggestions).toContain("anthropic")
+      }
+    },
+  })
+})
+
+test("getProvider returns undefined for nonexistent provider", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const provider = await Provider.getProvider("nonexistent")
+      expect(provider).toBeUndefined()
+    },
+  })
+})
+
+test("getProvider returns provider info", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const provider = await Provider.getProvider("anthropic")
+      expect(provider).toBeDefined()
+      expect(provider?.info.id).toBe("anthropic")
+    },
+  })
+})
+
+test("closest returns undefined when no partial match found", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const result = await Provider.closest("anthropic", ["nonexistent-xyz-model"])
+      expect(result).toBeUndefined()
+    },
+  })
+})
+
+test("closest checks multiple query terms in order", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      // First term won't match, second will
+      const result = await Provider.closest("anthropic", ["nonexistent", "haiku"])
+      expect(result).toBeDefined()
+      expect(result?.modelID).toContain("haiku")
+    },
+  })
+})
+
+test("model limit defaults to zero when not specified", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "no-limit": {
+              name: "No Limit Provider",
+              npm: "@ai-sdk/openai-compatible",
+              env: [],
+              models: {
+                model: {
+                  name: "Model",
+                  tool_call: true,
+                  // no limit specified
+                },
+              },
+              options: { apiKey: "test" },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["no-limit"].info.models["model"]
+      expect(model.limit.context).toBe(0)
+      expect(model.limit.output).toBe(0)
+    },
+  })
+})
+
+test("provider options are deeply merged", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              options: {
+                headers: {
+                  "X-Custom": "custom-value",
+                },
+                timeout: 30000,
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      // Custom options should be merged
+      expect(providers["anthropic"].options.timeout).toBe(30000)
+      expect(providers["anthropic"].options.headers["X-Custom"]).toBe("custom-value")
+      // anthropic custom loader adds its own headers, they should coexist
+      expect(providers["anthropic"].options.headers["anthropic-beta"]).toBeDefined()
+    },
+  })
+})