fix(config): isolate plugin list reads from a broken JSONC layer

Plugin listing still called readConfigFile per layer, so one unparseable
project file made GET /api/config/plugins and VS Code listPluginEntries
fail. Reuse readConfigLayer isolation and pin comment-only empty parse
in the VS Code suite.

Co-authored-by: serkraser <serkraser@gmail.com>

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

@@ -72,6 +72,7 @@ This module provides OpenCode server integration utilities for the web server ru
 - `parseMdFile(filePath)`, `writeMdFile(filePath, frontmatter, body)`: Markdown file operations with YAML frontmatter.
 - `getConfigPaths(workingDirectory)`, `readConfigLayers(workingDirectory)`, `readConfig(workingDirectory)`: Config file operations with layer merging (user, project, custom). `readConfigLayers` isolates `INVALID_JSONC` per layer: a broken file is omitted from the merge (`{}` for that layer only), recorded on `layerErrors`, and does not block valid sibling layers. Writes still refuse to overwrite the broken file.
 - `readConfigFile(filePath)`: Reads one config file. Missing, whitespace-only, and comment-only files (no JSON value) return `{}`. A `jsonc-parser` error that produces a partial or non-object tree throws `INVALID_JSONC` — partial parse trees must never be treated as authoritative (avoids rewriting a `$schema`-only stub over a full config).
+- `readConfigLayer(filePath)`: Same parse as `readConfigFile`, but isolates `INVALID_JSONC` to `{ config: {}, error }` so plugin/MCP/agent readers can skip one broken layer without aborting valid siblings. Writes still refuse to overwrite the broken file.
 - `writeConfig(config, filePath)`: Writes config with automatic backup. Refuses to overwrite an existing non-empty file that fails the same JSONC parse check.
 - `getJsonEntrySource(layers, sectionKey, entryName)`: Resolves which config layer provides an entry. A failed custom or user layer throws `INVALID_JSONC` instead of treating that file as empty. A failed project layer is skipped so a valid user/custom entry can still be found.
 - `getJsonWriteTarget(layers, preferredScope)`: Determines write target for config updates. Throws `INVALID_JSONC` when the chosen target file is the unparseable layer.

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

@@ -4,6 +4,7 @@ import path from 'path';
 import {
   AGENT_SCOPE,
   readConfigFile,
+  readConfigLayer,
   writeConfig,
 } from './shared.js';
 import { isPathSpec } from './plugin-spec.js';
@@ -111,15 +112,23 @@ function readPluginConfigLayers(workingDirectory) {
   const customPath = getActiveCustomConfigPath();
   const userPath = getPrimaryUserConfigPath();
   const projectPath = getProjectConfigPath(workingDirectory);
+  const userLayer = readConfigLayer(userPath);
+  const projectLayer = readConfigLayer(projectPath);
+  const customLayer = readConfigLayer(customPath);
   return {
-    userConfig: readConfigFile(userPath),
-    projectConfig: readConfigFile(projectPath),
-    customConfig: readConfigFile(customPath),
+    userConfig: userLayer.config,
+    projectConfig: projectLayer.config,
+    customConfig: customLayer.config,
     paths: {
       userPath,
       projectPath,
       customPath,
     },
+    layerErrors: [
+      userLayer.error && { path: userPath, code: userLayer.error.code, message: userLayer.error.message },
+      projectLayer.error && projectPath && { path: projectPath, code: projectLayer.error.code, message: projectLayer.error.message },
+      customLayer.error && customPath && { path: customPath, code: customLayer.error.code, message: customLayer.error.message },
+    ].filter(Boolean),
   };
 }
 

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

@@ -121,6 +121,24 @@ describe('opencode plugins data layer', () => {
     expect(readJson(userConfigPath)).toEqual({});
   });
 
+  test('lists user plugins when a project layer is unparseable', () => {
+    const partialProject = [
+      '{',
+      '  "$schema": "https://opencode.ai/config.json",',
+      '  plugin: ["broken-project-plugin"],',
+      '}',
+      '',
+    ].join('\n');
+    writeJson(userConfigPath, { plugin: ['user-plugin'] });
+    const projectFile = path.join(projectDir, '.opencode', 'opencode.jsonc');
+    fs.mkdirSync(path.dirname(projectFile), { recursive: true });
+    fs.writeFileSync(projectFile, partialProject, 'utf8');
+
+    expect(plugins.listPluginEntries(projectDir).map((entry) => entry.spec)).toEqual(['user-plugin']);
+    expect(fs.readFileSync(projectFile, 'utf8')).toBe(partialProject);
+    expect(fs.existsSync(`${projectFile}.openchamber.backup`)).toBe(false);
+  });
+
   test('lists entries from user and project layers with scopes and parsed kinds', () => {
     writeJson(userConfigPath, { plugin: ['npm-plugin', '/abs/plugin.js', '@scope/pkg@1.0.0'] });
     writeJson(path.join(projectDir, '.opencode', 'opencode.json'), { plugin: ['./local-plugin.js'] });

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

@@ -644,6 +644,7 @@ export {
   parseMdFile,
   writeMdFile,
   readConfigFile,
+  readConfigLayer,
   isPlainObject,
   readConfigLayers,
   readConfig,