fix custom provider edit to preserve config scope

Derive the effective OpenCode config layer (custom > project > user) from
provider sources and send it on PUT /api/provider so project/custom edits
update that layer instead of creating a global user override. Resolve
OPENCODE_CONFIG at call time and add UI/web/VS Code coverage for scoped
upserts.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

packages/web/server/lib/opencode/DOCUMENTATION.md

@@ -59,12 +59,12 @@ This module provides OpenCode server integration utilities for the web server ru
 
 ## Public exports (providers.js)
 - `getProviderSources(providerId, workingDirectory)`: Resolves which OpenCode config layers define a provider.
-- `upsertProviderConfig(providerId, config, workingDirectory, scope?, options?)`: Validates and writes a custom OpenAI-compatible provider block (`npm`, `name`, `options.baseURL`, `models`, optional `env`/`headers`) into the user/project/custom config layer. Does not store API keys. Requires `config.env` or `options.hasStoredAuth` (auth already written via OpenCode `auth.set`).
+- `upsertProviderConfig(providerId, config, workingDirectory, scope?, options?)`: Validates and writes a custom OpenAI-compatible provider block (`npm`, `name`, `options.baseURL`, `models`, optional `env`/`headers`) into the user/project/custom config layer. Does not store API keys. Requires `config.env` or `options.hasStoredAuth` (auth already written via OpenCode `auth.set`). Edit flows must pass the provider's effective existing layer (`custom` > `project` > `user`) so updates do not create a global user override.
 - `validateCustomProviderConfig(providerId, config, options?)`: Structural validation for custom provider payloads (id format, http(s) base URL, models, credentials via `env` or `hasStoredAuth`).
 - `removeProviderConfig(providerId, workingDirectory, scope?)`: Removes a provider block from the selected config layer.
 
 ## Public exports (shared.js)
-- `OPENCODE_CONFIG_DIR`, `AGENT_DIR`, `COMMAND_DIR`, `SKILL_DIR`, `CONFIG_FILE`, `CUSTOM_CONFIG_FILE`: Path constants.
+- `OPENCODE_CONFIG_DIR`, `AGENT_DIR`, `COMMAND_DIR`, `SKILL_DIR`, `CONFIG_FILE`: Path constants. `OPENCODE_CONFIG` is resolved at call time for the custom config layer path.
 - `AGENT_SCOPE`, `COMMAND_SCOPE`, `SKILL_SCOPE`: Scope constants with USER and PROJECT values.
 - `ensureDirs()`: Creates required OpenCode directories.
 - `parseMdFile(filePath)`, `writeMdFile(filePath, frontmatter, body)`: Markdown file operations with YAML frontmatter.
@@ -88,7 +88,7 @@ This module provides OpenCode server integration utilities for the web server ru
   - `GET /api/opencode/upgrade-status` (returns version availability plus the authoritative `upgrade.supported`, `upgrade.manager`, and `upgrade.reason` capability)
   - `POST /api/opencode/directory`
   - `GET /api/provider/:providerId/source`
-  - `PUT /api/provider` (create/update custom OpenAI-compatible provider config in OpenCode user/project/custom layers; secrets stay in auth via the OpenCode auth API)
+  - `PUT /api/provider` (create/update custom OpenAI-compatible provider config in OpenCode user/project/custom layers via `scope`; secrets stay in auth via the OpenCode auth API)
   - `DELETE /api/provider/:providerId/auth`
 - Owns lazy auth library loading for provider auth checks/removal.
 - Keeps route behavior independent from composition root; `index.js` now supplies dependencies only.

packages/web/server/lib/opencode/providers.test.js

@@ -169,4 +169,93 @@ describe('custom provider config persistence', () => {
     expect(result.providerId).toBe('keyed-provider');
     expect(result.config.env).toEqual(undefined);
   });
+
+  test('project-scope edit updates project layer without creating a user entry', () => {
+    const providerId = `proj-scope-${Date.now()}`;
+    const configPath = path.join(projectDir, 'opencode.json');
+
+    upsertProviderConfig(providerId, {
+      name: 'Project Scoped',
+      options: { baseURL: 'https://project.example.com/v1' },
+      models: { m: { name: 'M' } },
+    }, projectDir, 'project', { hasStoredAuth: true });
+
+    upsertProviderConfig(providerId, {
+      name: 'Project Scoped Updated',
+      options: { baseURL: 'https://project.example.com/v2', headers: { 'X-Project': '1' } },
+      models: { m: { name: 'M2' } },
+    }, projectDir, 'project', { hasStoredAuth: true });
+
+    const written = readJson(configPath);
+    expect(written.provider[providerId]).toEqual({
+      npm: '@ai-sdk/openai-compatible',
+      name: 'Project Scoped Updated',
+      options: {
+        baseURL: 'https://project.example.com/v2',
+        headers: { 'X-Project': '1' },
+      },
+      models: { m: { name: 'M2' } },
+    });
+
+    const sources = getProviderSources(providerId, projectDir);
+    expect(sources.sources.project.exists).toBe(true);
+    expect(sources.sources.user.exists).toBe(false);
+    expect(sources.sources.custom.exists).toBe(false);
+
+    for (const userPath of [
+      path.join(os.homedir(), '.config', 'opencode', 'opencode.json'),
+      path.join(os.homedir(), '.config', 'opencode', 'config.json'),
+    ]) {
+      if (!fs.existsSync(userPath)) continue;
+      const userConfig = readJson(userPath);
+      expect(userConfig.provider?.[providerId]).toBeUndefined();
+      expect(userConfig.providers?.[providerId]).toBeUndefined();
+    }
+  });
+
+  test('custom-scope edit updates custom layer without creating a user entry', () => {
+    const providerId = `custom-scope-${Date.now()}`;
+    const customPath = path.join(projectDir, 'custom-opencode.json');
+    const previousEnv = process.env.OPENCODE_CONFIG;
+    process.env.OPENCODE_CONFIG = customPath;
+
+    try {
+      upsertProviderConfig(providerId, {
+        name: 'Custom Scoped',
+        options: { baseURL: 'https://custom.example.com/v1' },
+        models: { m: { name: 'M' } },
+      }, projectDir, 'custom', { hasStoredAuth: true });
+
+      upsertProviderConfig(providerId, {
+        name: 'Custom Scoped Updated',
+        options: { baseURL: 'https://custom.example.com/v2' },
+        models: { n: { name: 'N' } },
+      }, projectDir, 'custom', { hasStoredAuth: true });
+
+      const written = readJson(customPath);
+      expect(written.provider[providerId].name).toBe('Custom Scoped Updated');
+      expect(written.provider[providerId].options.baseURL).toBe('https://custom.example.com/v2');
+
+      const sources = getProviderSources(providerId, projectDir);
+      expect(sources.sources.custom.exists).toBe(true);
+      expect(sources.sources.user.exists).toBe(false);
+      expect(sources.sources.project.exists).toBe(false);
+
+      for (const userPath of [
+        path.join(os.homedir(), '.config', 'opencode', 'opencode.json'),
+        path.join(os.homedir(), '.config', 'opencode', 'config.json'),
+      ]) {
+        if (!fs.existsSync(userPath)) continue;
+        const userConfig = readJson(userPath);
+        expect(userConfig.provider?.[providerId]).toBeUndefined();
+        expect(userConfig.providers?.[providerId]).toBeUndefined();
+      }
+    } finally {
+      if (previousEnv === undefined) {
+        delete process.env.OPENCODE_CONFIG;
+      } else {
+        process.env.OPENCODE_CONFIG = previousEnv;
+      }
+    }
+  });
 });

packages/web/server/lib/opencode/shared.js

@@ -11,9 +11,6 @@ const AGENT_DIR = path.join(OPENCODE_CONFIG_DIR, 'agents');
 const COMMAND_DIR = path.join(OPENCODE_CONFIG_DIR, 'commands');
 const SKILL_DIR = path.join(OPENCODE_CONFIG_DIR, 'skills');
 const CONFIG_FILE = path.join(OPENCODE_CONFIG_DIR, 'config.json');
-const CUSTOM_CONFIG_FILE = process.env.OPENCODE_CONFIG
-  ? path.resolve(process.env.OPENCODE_CONFIG)
-  : null;
 const PROMPT_FILE_PATTERN = /^\{file:(.+)\}$/i;
 
 // ============== SCOPE TYPE CONSTANTS ==============
@@ -121,7 +118,10 @@ function getConfigPaths(workingDirectory) {
       path.join(OPENCODE_CONFIG_DIR, 'opencode.jsonc'),
     ],
     projectPath: getProjectConfigPath(workingDirectory),
-    customPath: CUSTOM_CONFIG_FILE
+    // Resolve at call time so OPENCODE_CONFIG changes (and tests) take effect.
+    customPath: process.env.OPENCODE_CONFIG
+      ? path.resolve(process.env.OPENCODE_CONFIG)
+      : null,
   };
 }