diff --git a/bin/cli/commands/setup-opencode.mjs b/bin/cli/commands/setup-opencode.mjs
index cddc867233..f2d5889f22 100644
--- a/bin/cli/commands/setup-opencode.mjs
+++ b/bin/cli/commands/setup-opencode.mjs
@@ -2,7 +2,7 @@
  * omniroute setup-opencode — Remote-aware OpenCode provider generator
  * (openai-compatible). Distinct from `omniroute setup opencode` (which wires the
  * @omniroute/opencode-plugin). This writes the `omniroute` provider into
- * ~/.config/opencode/opencode.json with every catalog model, so you can run
+ * the active OpenCode JSON/JSONC config with every catalog model, so you can run
  * `opencode -m omniroute/<model>`.
  *
  * Reuses the proven server-side generator (config-generator/opencode.ts) for the
@@ -10,12 +10,13 @@
  */
 
 import { existsSync, mkdirSync, writeFileSync } from "node:fs";
-import { join } from "node:path";
-import os from "node:os";
+import { basename, dirname } from "node:path";
+import { applyEdits, modify, parse, printParseErrorCode } from "jsonc-parser";
 import { printHeading, printInfo, printSuccess, printError } from "../io.mjs";
 import { resolveActiveContext } from "../contexts.mjs";
 
 const ENV_KEY_REF = "{env:OMNIROUTE_API_KEY}";
+const JSON_FORMATTING_OPTIONS = { insertSpaces: true, tabSize: 2 };
 
 /** Resolve baseUrl + (literal) apiKey from flags → active context → localhost. */
 export function resolveOpencodeTarget(opts = {}) {
@@ -29,7 +30,8 @@ export function resolveOpencodeTarget(opts = {}) {
     } catch {
       /* no context */
     }
-    if (!baseUrl) baseUrl = `http://localhost:${Number(opts.port ?? process.env.PORT ?? 20128) || 20128}`;
+    if (!baseUrl)
+      baseUrl = `http://localhost:${Number(opts.port ?? process.env.PORT ?? 20128) || 20128}`;
   }
 
   let apiKey = opts.apiKey ?? opts["api-key"];
@@ -48,32 +50,61 @@ export function resolveOpencodeTarget(opts = {}) {
 /**
  * Post-process the generator output: reference the API key by env var (keep the
  * secret off disk) and optionally keep only models whose id matches `only`.
- * Pure + testable. Returns the final JSON string.
+ * Pure + testable. Returns the final JSONC string while preserving comments
+ * outside the OmniRoute-managed fields.
  *
  * @param {string} rawJson  output of generateOpencodeConfig
  * @param {{ only?: string[] }} [opts]
  * @returns {{ json: string, modelCount: number }}
  */
 export function postProcessOpencodeConfig(rawJson, opts = {}) {
-  const config = JSON.parse(rawJson);
-  const prov = config.provider?.omniroute;
-  if (prov?.options) prov.options.apiKey = ENV_KEY_REF;
+  const errors = [];
+  const config = parse(rawJson, errors, { allowTrailingComma: true, disallowComments: false });
+  if (errors.length > 0 || !config || typeof config !== "object" || Array.isArray(config)) {
+    const details = errors
+      .map((error) => `${printParseErrorCode(error.error)} at offset ${error.offset}`)
+      .join(", ");
+    throw new Error(`Failed to parse generated OpenCode config${details ? `: ${details}` : ""}`);
+  }
 
+  const prov = config.provider?.omniroute;
+  let json = rawJson;
+  if (prov?.options) {
+    json = applyEdits(
+      json,
+      modify(json, ["provider", "omniroute", "options", "apiKey"], ENV_KEY_REF, {
+        formattingOptions: JSON_FORMATTING_OPTIONS,
+      })
+    );
+  }
+
+  let models = prov?.models;
   if (opts.only && opts.only.length && prov?.models) {
     const kept = {};
     for (const [id, entry] of Object.entries(prov.models)) {
       if (opts.only.some((f) => id.includes(f))) kept[id] = entry;
     }
-    prov.models = kept;
+    models = kept;
+    json = applyEdits(
+      json,
+      modify(json, ["provider", "omniroute", "models"], kept, {
+        formattingOptions: JSON_FORMATTING_OPTIONS,
+      })
+    );
   }
-  const modelCount = prov?.models ? Object.keys(prov.models).length : 0;
-  return { json: JSON.stringify(config, null, 2) + "\n", modelCount };
+  const modelCount = models ? Object.keys(models).length : 0;
+  return { json: json.endsWith("\n") ? json : `${json}\n`, modelCount };
 }
 
 export async function runSetupOpencodeCommand(opts = {}) {
   const { baseUrl, apiKey } = resolveOpencodeTarget(opts);
   const dryRun = Boolean(opts.dryRun ?? opts["dry-run"]);
-  const only = opts.only ? opts.only.split(",").map((s) => s.trim()).filter(Boolean) : null;
+  const only = opts.only
+    ? opts.only
+        .split(",")
+        .map((s) => s.trim())
+        .filter(Boolean)
+    : null;
 
   printHeading("OmniRoute → OpenCode provider (openai-compatible)");
   printInfo(`Connecting to ${baseUrl} …`);
@@ -81,20 +112,28 @@ export async function runSetupOpencodeCommand(opts = {}) {
   // Deferred import: opencode.ts is TypeScript; tsx is registered by
   // bin/omniroute.mjs before any command runs, so importing here is safe.
   let raw;
+  let configPath;
   try {
-    const { generateOpencodeConfig } = await import(
-      "../../../src/lib/cli-helper/config-generator/opencode.ts"
-    );
-    raw = await generateOpencodeConfig({ baseUrl, apiKey, model: opts.model, providerId: "omniroute" });
+    const { generateOpencodeConfig } =
+      await import("../../../src/lib/cli-helper/config-generator/opencode.ts");
+    const { resolveOpencodeConfigPath } =
+      await import("../../../src/shared/services/opencodeConfigPath.ts");
+    configPath = resolveOpencodeConfigPath();
+    raw = await generateOpencodeConfig({
+      baseUrl,
+      apiKey,
+      model: opts.model,
+      providerId: "omniroute",
+      configPath,
+    });
   } catch (err) {
-    printError(`Failed to generate opencode.json: ${err?.message || err}`);
+    printError(`Failed to generate OpenCode config: ${err?.message || err}`);
     printInfo("Make sure OmniRoute is running and --remote/--api-key are correct.");
     return 1;
   }
 
   const { json, modelCount } = postProcessOpencodeConfig(raw, { only });
-  const configDir = join(os.homedir(), ".config", "opencode");
-  const configPath = join(configDir, "opencode.json");
+  const configDir = dirname(configPath);
 
   if (dryRun) {
     console.log(json.length > 4000 ? json.slice(0, 4000) + "\n… (truncated)" : json);
@@ -104,7 +143,9 @@ export async function runSetupOpencodeCommand(opts = {}) {
 
   if (!existsSync(configDir)) mkdirSync(configDir, { recursive: true });
   writeFileSync(configPath, json, "utf8");
-  printSuccess(`opencode.json updated at ${configPath} (${modelCount} models under 'omniroute')`);
+  printSuccess(
+    `${basename(configPath)} updated at ${configPath} (${modelCount} models under 'omniroute')`
+  );
   printInfo('Use it:  opencode -m omniroute/<model> "..."   (export OMNIROUTE_API_KEY first)');
   return 0;
 }
@@ -113,7 +154,7 @@ export function registerSetupOpencode(program) {
   program
     .command("setup-opencode")
     .description(
-      "Generate the OmniRoute openai-compatible provider in ~/.config/opencode/opencode.json " +
+      "Generate the OmniRoute openai-compatible provider in the active OpenCode config " +
         "from the live model catalog (local or remote VPS)"
     )
     .option("--port <port>", "Local OmniRoute port (ignored when --remote is set)", "20128")
diff --git a/changelog.d/fixes/pending-opencode-jsonc-config.md b/changelog.d/fixes/pending-opencode-jsonc-config.md
new file mode 100644
index 0000000000..0951ae78f2
--- /dev/null
+++ b/changelog.d/fixes/pending-opencode-jsonc-config.md
@@ -0,0 +1 @@
+- **fix(cli):** recognize native `opencode.jsonc` files in OpenCode detection, generated-provider setup, and dashboard save/apply flows; preserve unrelated JSONC comments and provider settings, write updates back to the selected file, and refuse to overwrite invalid config ([#10227](https://github.com/diegosouzapw/OmniRoute/issues/10227)) — thanks @tito13kfm
diff --git a/src/app/api/cli-tools/apply/route.ts b/src/app/api/cli-tools/apply/route.ts
index fc5a066615..b0235df1ee 100644
--- a/src/app/api/cli-tools/apply/route.ts
+++ b/src/app/api/cli-tools/apply/route.ts
@@ -17,7 +17,6 @@ const applySchema = z.object({
 const TOOL_CONFIG_PATHS: Record<string, string> = {
   claude: path.join(os.homedir(), ".claude", "settings.json"),
   codex: path.join(os.homedir(), ".codex", "config.yaml"),
-  opencode: path.join(os.homedir(), ".config", "opencode", "opencode.json"),
   cline: path.join(os.homedir(), ".cline", "data", "globalState.json"),
   kilocode: path.join(os.homedir(), ".config", "kilocode", "settings.json"),
   continue: path.join(os.homedir(), ".continue", "config.yaml"),
@@ -65,7 +64,7 @@ export async function POST(request: Request) {
       });
     }
 
-    const configPath = TOOL_CONFIG_PATHS[toolId];
+    const configPath = toolId === "opencode" ? result.configPath : TOOL_CONFIG_PATHS[toolId];
     if (!configPath) {
       return NextResponse.json({ error: `Unknown tool: ${toolId}` }, { status: 400 });
     }
diff --git a/src/app/api/cli-tools/guide-settings/[toolId]/route.ts b/src/app/api/cli-tools/guide-settings/[toolId]/route.ts
index 002ee40113..b0487d304b 100644
--- a/src/app/api/cli-tools/guide-settings/[toolId]/route.ts
+++ b/src/app/api/cli-tools/guide-settings/[toolId]/route.ts
@@ -64,7 +64,7 @@ export async function POST(request, { params }) {
         return await saveContinueConfig({ baseUrl, apiKey, model });
       case "opencode":
         // (#524) OpenCode config was never saved because only 'continue' was handled here.
-        // OpenCode reads ~/.config/opencode/opencode.json — write the OmniRoute settings there.
+        // OpenCode reads opencode.jsonc/opencode.json — update the active native config.
         return await saveOpenCodeConfig({ baseUrl, apiKey, model, models, modelLabels });
       case "hermes":
         return await saveHermesConfig({ baseUrl, apiKey, model });
@@ -161,7 +161,7 @@ async function saveContinueConfig({ baseUrl, apiKey, model }) {
 }
 
 /**
- * Save OpenCode config to ~/.config/opencode/opencode.json on ALL platforms
+ * Save OpenCode config to the active opencode.jsonc/opencode.json on ALL platforms
  * (XDG_CONFIG_HOME aware). OpenCode uses XDG `~/.config` even on Windows
  * (%USERPROFILE%\.config), NOT %APPDATA% (#3330).
  *
@@ -182,8 +182,9 @@ async function saveOpenCodeConfig({ baseUrl, apiKey, model, models, modelLabels
   let existingConfigText = "";
   try {
     existingConfigText = await fs.readFile(configPath, "utf-8");
-  } catch {
-    // File doesn't exist — start fresh
+  } catch (error) {
+    if ((error as NodeJS.ErrnoException).code !== "ENOENT") throw error;
+    // File doesn't exist — start fresh.
   }
 
   const nextConfigText = mergeOpenCodeConfigText(existingConfigText, {
diff --git a/src/lib/cli-helper/config-generator/index.ts b/src/lib/cli-helper/config-generator/index.ts
index 24eac4f41a..343ef26a78 100644
--- a/src/lib/cli-helper/config-generator/index.ts
+++ b/src/lib/cli-helper/config-generator/index.ts
@@ -10,6 +10,7 @@ import { generateHermesConfig } from "./hermes";
 import { generateHermesAgentConfig, type HermesAgentConfigPayload } from "./hermes-agent";
 import { generateKilocodeConfig } from "./kilocode";
 import { generateOpencodeConfig } from "./opencode";
+import { resolveOpencodeConfigPath } from "../../../shared/services/opencodeConfigPath";
 
 export interface GenerateOptions {
   baseUrl: string;
@@ -42,7 +43,6 @@ function expandHome(p: string): string {
 const STATIC_TOOL_CONFIG_PATHS: Record<string, string> = {
   claude: path.join(os.homedir(), ".claude", "settings.json"),
   codex: path.join(os.homedir(), ".codex", "config.yaml"),
-  opencode: path.join(os.homedir(), ".config", "opencode", "opencode.json"),
   cline: path.join(os.homedir(), ".cline", "data", "globalState.json"),
   kilocode: path.join(os.homedir(), ".config", "kilocode", "settings.json"),
   continue: path.join(os.homedir(), ".continue", "config.yaml"),
@@ -58,6 +58,9 @@ function getToolConfigPath(toolId: string): string {
   if (toolId === "hermes" || toolId === "hermes-agent") {
     return getHermesConfigPath();
   }
+  if (toolId === "opencode") {
+    return resolveOpencodeConfigPath();
+  }
   return STATIC_TOOL_CONFIG_PATHS[toolId] ?? "";
 }
 
@@ -95,8 +98,11 @@ export async function generateConfig(
     if (!generate) {
       return { success: false, configPath: "", error: `Unknown tool: ${toolId}` };
     }
-    const content = await generate(options);
     const configPath = getToolConfigPath(toolId);
+    const content =
+      toolId === "opencode"
+        ? await generateOpencodeConfig({ ...options, configPath })
+        : await generate(options);
     return { success: true, configPath, content };
   } catch (err) {
     const msg = err instanceof Error ? err.message : String(err);
diff --git a/src/lib/cli-helper/config-generator/opencode.ts b/src/lib/cli-helper/config-generator/opencode.ts
index 3a5f900826..c2915e5eb7 100644
--- a/src/lib/cli-helper/config-generator/opencode.ts
+++ b/src/lib/cli-helper/config-generator/opencode.ts
@@ -1,13 +1,13 @@
-import path from "node:path";
-import os from "node:os";
 import fs from "node:fs";
+import { applyEdits, modify, parse, printParseErrorCode, type ParseError } from "jsonc-parser";
 import {
   parseOutboundUrl,
   isCloudMetadataHost,
   OutboundUrlGuardError,
 } from "../../../shared/network/outboundUrlGuard";
+import { resolveOpencodeConfigPath } from "../../../shared/services/opencodeConfigPath";
 
-const CONFIG_PATH = path.join(os.homedir(), ".config", "opencode", "opencode.json");
+const JSON_FORMATTING_OPTIONS = { insertSpaces: true, tabSize: 2 } as const;
 
 /**
  * SSRF guard for the catalog fetch (CodeQL js/request-forgery #326). The catalog
@@ -185,7 +185,8 @@ function deriveOpenCodeCapabilities(
   catalog: CatalogModelEntry | undefined,
   existing: ExistingModelEntry | undefined
 ): Pick<ExistingModelEntry, "attachment" | "reasoning" | "temperature" | "tool_call"> {
-  const result: Pick<ExistingModelEntry, "attachment" | "reasoning" | "temperature" | "tool_call"> = {};
+  const result: Pick<ExistingModelEntry, "attachment" | "reasoning" | "temperature" | "tool_call"> =
+    {};
 
   // attachment: explicit user flag wins, then catalog attachment, then vision, then image modality.
   if (typeof existing?.attachment === "boolean") {
@@ -324,26 +325,81 @@ function buildModelEntry(
 }
 
 /**
- * Load the user's current opencode.json (if any) so we can preserve names,
- * capability flags, and explicit `limit.context` overrides. JSONC comments
- * are not supported — we parse as plain JSON. If parsing fails, we fall
- * back to an empty config; the resulting write will lose comments, but
- * that matches the existing CLI behavior of `config set opencode`.
+ * Load the user's current OpenCode config so we can preserve names,
+ * capability flags, explicit `limit.context` overrides, and JSONC source text.
+ * Existing invalid files are a hard stop: replacing one with a regenerated
+ * document would silently lose comments, unrelated providers, and settings.
  */
-function loadExistingConfig(): ExistingConfig {
+function loadExistingConfig(configPath: string): { config: ExistingConfig; source: string | null } {
+  if (!fs.existsSync(configPath)) return { config: {}, source: null };
+
+  let source: string;
   try {
-    if (!fs.existsSync(CONFIG_PATH)) return {};
-    const raw = fs.readFileSync(CONFIG_PATH, "utf8");
-    return JSON.parse(raw) as ExistingConfig;
-  } catch {
-    return {};
+    source = fs.readFileSync(configPath, "utf8");
+  } catch (error) {
+    const message = error instanceof Error ? error.message : String(error);
+    throw new Error(`Failed to read existing OpenCode config at ${configPath}: ${message}`);
   }
+
+  const errors: ParseError[] = [];
+  const parsed = parse(source, errors, { allowTrailingComma: true, disallowComments: false });
+  if (errors.length > 0 || !parsed || typeof parsed !== "object" || Array.isArray(parsed)) {
+    const detail = errors[0] ? printParseErrorCode(errors[0].error) : "root must be an object";
+    throw new Error(
+      `Existing OpenCode config at ${configPath} is invalid JSONC (${detail}); refusing to overwrite it.`
+    );
+  }
+
+  return { config: parsed as ExistingConfig, source };
+}
+
+/**
+ * Patch the generated values into an existing JSONC document without replacing
+ * its comments or unrelated keys. The generated object is authoritative for
+ * the fields the generator manages; everything else remains byte-for-byte
+ * unless jsonc-parser must adjust nearby whitespace for an edit.
+ */
+function mergeGeneratedConfigText(
+  existingSource: string | null,
+  existingConfig: ExistingConfig,
+  generatedConfig: Record<string, unknown>,
+  providerId: string
+): string {
+  if (existingSource === null) return JSON.stringify(generatedConfig, null, 2);
+
+  let nextText = existingSource;
+  const schemaEdits = modify(nextText, ["$schema"], generatedConfig.$schema, {
+    formattingOptions: JSON_FORMATTING_OPTIONS,
+  });
+  nextText = applyEdits(nextText, schemaEdits);
+
+  const generatedProvider = (
+    generatedConfig.provider as Record<string, ExistingProviderEntry> | undefined
+  )?.[providerId];
+  const providerEdits = modify(nextText, ["provider", providerId], generatedProvider, {
+    formattingOptions: JSON_FORMATTING_OPTIONS,
+  });
+  nextText = applyEdits(nextText, providerEdits);
+
+  if (generatedConfig.model !== existingConfig.model) {
+    const modelEdits = modify(nextText, ["model"], generatedConfig.model, {
+      formattingOptions: JSON_FORMATTING_OPTIONS,
+    });
+    nextText = applyEdits(nextText, modelEdits);
+  }
+
+  return nextText;
 }
 
 export interface GenerateOpencodeOptions {
   baseUrl: string;
   apiKey: string;
   model?: string;
+  /**
+   * Pre-resolved destination used by the API generator/apply pipeline so the
+   * file read for merging is guaranteed to be the file later written.
+   */
+  configPath?: string;
   /**
    * Override the default `provider.id` used in the generated config.
    * Defaults to `"omniroute"`.
@@ -389,6 +445,8 @@ export async function generateOpencodeConfig(options: GenerateOpencodeOptions):
   const providerId = options.providerId?.trim() || "omniroute";
   const fetchCatalog = options.fetchCatalog !== false;
   const timeoutMs = options.catalogTimeoutMs ?? 5_000;
+  const configPath = options.configPath ?? resolveOpencodeConfigPath();
+  const { config: existing, source: existingSource } = loadExistingConfig(configPath);
 
   // Fetch live catalog. The catalog is the source of truth — if it fails,
   // we refuse to write an opencode.json that could mislead OpenCode into
@@ -407,7 +465,6 @@ export async function generateOpencodeConfig(options: GenerateOpencodeOptions):
 
   // Load existing config so we preserve names, capability flags, and any
   // explicit `limit.context` overrides the user has set.
-  const existing = loadExistingConfig();
   const existingProvider = existing.provider?.[providerId];
   const existingModels = (existingProvider?.models ?? {}) as Record<string, ExistingModelEntry>;
 
@@ -465,7 +522,7 @@ export async function generateOpencodeConfig(options: GenerateOpencodeOptions):
     config.small_model = existing.small_model;
   }
 
-  return JSON.stringify(config, null, 2);
+  return mergeGeneratedConfigText(existingSource, existing, config, providerId);
 }
 
 /**
diff --git a/src/lib/cli-helper/tool-detector.ts b/src/lib/cli-helper/tool-detector.ts
index 48b03bb555..59a6030b8c 100644
--- a/src/lib/cli-helper/tool-detector.ts
+++ b/src/lib/cli-helper/tool-detector.ts
@@ -8,6 +8,7 @@ import {
   locateCommand,
   shouldUseShellForCommand,
 } from "../../shared/services/cliRuntime";
+import { resolveOpencodeConfigPath } from "../../shared/services/opencodeConfigPath";
 
 const execFileAsync = promisify(execFile);
 let execFileImpl = execFileAsync;
@@ -44,7 +45,7 @@ export interface DetectedTool {
 const TOOLS = [
   { id: "claude", name: "Claude Code", configPath: "~/.claude/settings.json" },
   { id: "codex", name: "Codex CLI", configPath: "~/.codex/config.yaml" },
-  { id: "opencode", name: "OpenCode", configPath: "~/.config/opencode/opencode.json" },
+  { id: "opencode", name: "OpenCode", configPath: resolveOpencodeConfigPath },
   { id: "cline", name: "Cline", configPath: "~/.cline/data/globalState.json" },
   { id: "kilocode", name: "Kilo Code", configPath: "~/.config/kilocode/settings.json" },
   { id: "continue", name: "Continue", configPath: "~/.continue/config.yaml" },
@@ -149,8 +150,9 @@ export async function detectTool(id: string): Promise<DetectedTool | null> {
   if (!tool) return null;
 
   const { installed, version } = await detectBinary(tool.id);
-  const configPath = expandHome(tool.configPath);
-  const configContents = await readConfigFile(tool.configPath);
+  const configPath =
+    typeof tool.configPath === "function" ? tool.configPath() : expandHome(tool.configPath);
+  const configContents = await readConfigFile(configPath);
   const configured = !!configContents && isConfigured(configContents, "http://localhost:20128");
 
   const result: DetectedTool = {
diff --git a/src/shared/constants/cliTools.ts b/src/shared/constants/cliTools.ts
index 41bed13270..d66927f96a 100644
--- a/src/shared/constants/cliTools.ts
+++ b/src/shared/constants/cliTools.ts
@@ -281,7 +281,7 @@ export const CLI_TOOLS: Record<string, CliCatalogEntry> = {
     notes: [
       {
         type: "warning",
-        text: "Config path: ~/.config/opencode/opencode.json on all platforms (Windows: %USERPROFILE%\\\\.config\\\\opencode\\\\opencode.json)",
+        text: "Config paths: ~/.config/opencode/opencode.jsonc (preferred when present) or opencode.json on all platforms (Windows: %USERPROFILE%\\\\.config\\\\opencode\\\\opencode.jsonc or opencode.json)",
       },
       {
         type: "warning",
diff --git a/src/shared/services/cliRuntime.ts b/src/shared/services/cliRuntime.ts
index 6cc590ee47..bf148aa87c 100644
--- a/src/shared/services/cliRuntime.ts
+++ b/src/shared/services/cliRuntime.ts
@@ -9,6 +9,10 @@ import { withSettingsFallback } from "./cliInstallFallback";
 import { GROK_BUILD_RUNTIME_ENTRY, AMP_RUNTIME_ENTRY } from "./cliRuntimeGrokBuild";
 import { isLocationTrusted, findKnownPathMatch } from "./cliRuntimeKnownPath";
 import { buildHealthcheckPath } from "./cliRuntimeHealthcheckPath";
+import {
+  resolveOpencodeConfigDir as resolveOpenCodeConfigDir,
+  resolveOpencodeConfigPath as resolveOpenCodeConfigPath,
+} from "./opencodeConfigPath";
 const VALID_RUNTIME_MODES = new Set(["auto", "host", "container"]);
 const FALSE_VALUES = new Set(["0", "false", "no", "off"]);
 
@@ -979,15 +983,14 @@ export const resolveOpencodeConfigDir = (
   // `%APPDATA%`. Writing to %APPDATA% on Windows put the file where OpenCode
   // never looks, so dashboard-saved config silently had no effect. `_platform`
   // is kept in the signature for call-site/test compatibility.
-  const xdgConfigHome = String(env.XDG_CONFIG_HOME || "").trim();
-  return xdgConfigHome || path.join(homeDir, ".config");
+  return path.dirname(resolveOpenCodeConfigDir(env, homeDir));
 };
 
 export const resolveOpencodeConfigPath = (
-  platform = process.platform,
+  _platform = process.platform,
   env: NodeJS.ProcessEnv = process.env,
   homeDir = os.homedir()
-) => path.join(resolveOpencodeConfigDir(platform, env, homeDir), "opencode", "opencode.json");
+) => resolveOpenCodeConfigPath(env, homeDir);
 
 export const getOpenCodeConfigPath = () => resolveOpencodeConfigPath();
 
diff --git a/src/shared/services/opencodeConfig.ts b/src/shared/services/opencodeConfig.ts
index 89cac6a6f6..c597bea4d5 100644
--- a/src/shared/services/opencodeConfig.ts
+++ b/src/shared/services/opencodeConfig.ts
@@ -1,4 +1,4 @@
-import { applyEdits, modify, parse } from "jsonc-parser";
+import { applyEdits, modify, parse, printParseErrorCode, type ParseError } from "jsonc-parser";
 
 type OpenCodeConfigInput = {
   baseUrl?: string;
@@ -113,11 +113,16 @@ export const mergeOpenCodeConfigText = (
     return JSON.stringify(buildOpenCodeConfigDocument(input), null, 2);
   }
 
-  const errors: { error: number }[] = [];
+  const errors: ParseError[] = [];
   const parsed = parse(content, errors, { allowTrailingComma: true, disallowComments: false });
 
   if (errors.length > 0 || !parsed || typeof parsed !== "object" || Array.isArray(parsed)) {
-    return JSON.stringify(mergeOpenCodeConfig({}, input), null, 2);
+    const detail = errors[0]
+      ? `${printParseErrorCode(errors[0].error)} at offset ${errors[0].offset}`
+      : "root must be an object";
+    throw new Error(
+      `Existing OpenCode config is invalid JSONC (${detail}); refusing to overwrite it.`
+    );
   }
 
   let nextText = content;
diff --git a/src/shared/services/opencodeConfigPath.ts b/src/shared/services/opencodeConfigPath.ts
new file mode 100644
index 0000000000..ce5eca8451
--- /dev/null
+++ b/src/shared/services/opencodeConfigPath.ts
@@ -0,0 +1,37 @@
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+export const OPENCODE_JSON_FILENAME = "opencode.json";
+export const OPENCODE_JSONC_FILENAME = "opencode.jsonc";
+
+export const resolveOpencodeConfigDir = (
+  env: NodeJS.ProcessEnv = process.env,
+  homeDir = os.homedir()
+): string => {
+  const xdgConfigHome = String(env.XDG_CONFIG_HOME || "").trim();
+  return path.join(xdgConfigHome || path.join(homeDir, ".config"), "opencode");
+};
+
+/**
+ * Resolve the global OpenCode config file that a write should update.
+ *
+ * OpenCode treats `opencode.jsonc` as the preferred writable global config and
+ * merges it after `opencode.json` when both exist. Match that precedence so an
+ * existing JSONC document is never shadowed by a newly-created JSON file. Keep
+ * `opencode.json` as OmniRoute's creation default for backwards compatibility
+ * when neither native filename exists.
+ */
+export const resolveOpencodeConfigPath = (
+  env: NodeJS.ProcessEnv = process.env,
+  homeDir = os.homedir()
+): string => {
+  const configDir = resolveOpencodeConfigDir(env, homeDir);
+  const jsoncPath = path.join(configDir, OPENCODE_JSONC_FILENAME);
+  if (fs.existsSync(jsoncPath)) return jsoncPath;
+
+  const jsonPath = path.join(configDir, OPENCODE_JSON_FILENAME);
+  if (fs.existsSync(jsonPath)) return jsonPath;
+
+  return jsonPath;
+};
diff --git a/tests/unit/cli-helper/config-generator.test.ts b/tests/unit/cli-helper/config-generator.test.ts
index d993df449d..c20a91c51b 100644
--- a/tests/unit/cli-helper/config-generator.test.ts
+++ b/tests/unit/cli-helper/config-generator.test.ts
@@ -2,6 +2,7 @@ import { describe, it, mock } from "node:test";
 import assert from "node:assert";
 import fs, { readFileSync } from "node:fs";
 import { fileURLToPath } from "node:url";
+import { parse } from "jsonc-parser";
 import * as generator from "../../../src/lib/cli-helper/config-generator/index.ts";
 
 // The UI's HERMES_ROLES catalog (HermesAgentToolCard.tsx) is a "use client" component
@@ -261,7 +262,7 @@ describe("config-generator", () => {
           { role: "delegation", model: "claude-3-5-sonnet" },
           { role: "vision", model: "gpt-4o" },
         ],
-      });
+      } as any);
 
       assert.ok(!result.error);
       assert.ok(typeof result.yaml === "string");
@@ -291,7 +292,7 @@ describe("config-generator", () => {
       const result = await hermesAgent.generateHermesAgentConfig({
         baseUrl: "",
         selections: [{ role: "default", model: "x" }],
-      } as any);
+      });
 
       assert.ok(result.error);
       assert.ok(result.error.includes("baseUrl"));
@@ -513,9 +514,8 @@ describe("config-generator", () => {
         ])
       );
       try {
-        const { generateOpencodeConfig } = await import(
-          "../../../src/lib/cli-helper/config-generator/opencode.ts"
-        );
+        const { generateOpencodeConfig } =
+          await import("../../../src/lib/cli-helper/config-generator/opencode.ts");
         const out = await generateOpencodeConfig({
           baseUrl: "http://localhost:20128",
           apiKey: "sk-test",
@@ -653,5 +653,70 @@ describe("config-generator", () => {
         mock.restoreAll();
       }
     });
+
+    it("loads comments and trailing commas from opencode.jsonc and returns its real path (#10227)", async () => {
+      const existingJsonc = `{
+  // preserve this native OpenCode file instead of ignoring it
+  "$schema": "https://opencode.ai/config.json",
+  "provider": {
+    "custom": {
+      // keep comments inside unrelated providers too
+      "name": "Custom Provider"
+    },
+    "omniroute": {
+      "models": {
+        "manual-model": { "name": "Manual", "limit": { "context": 77777, }, },
+      },
+    },
+  },
+}\n`;
+      let readPath = "";
+      mock.method(fs, "existsSync", (candidate) => String(candidate).endsWith("opencode.jsonc"));
+      mock.method(fs, "readFileSync", (candidate) => {
+        readPath = String(candidate);
+        return existingJsonc;
+      });
+      const stub = stubFetchOnce(
+        makeCatalogResponse([{ id: "manual-model", context_length: 131072 }])
+      );
+
+      try {
+        const result = await generator.generateConfig("opencode", {
+          baseUrl: "http://localhost:20128",
+          apiKey: "sk-test",
+        });
+
+        assert.strictEqual(result.success, true);
+        assert.match(result.configPath, /opencode\.jsonc$/);
+        assert.strictEqual(readPath, result.configPath);
+        assert.match(result.content || "", /preserve this native OpenCode file/);
+        assert.match(result.content || "", /keep comments inside unrelated providers too/);
+        const config = parse(result.content || "");
+        assert.deepStrictEqual(config.provider.custom, { name: "Custom Provider" });
+        assert.strictEqual(config.provider.omniroute.models["manual-model"].limit.context, 77777);
+      } finally {
+        stub.restore();
+        mock.restoreAll();
+      }
+    });
+
+    it("refuses to replace an invalid existing opencode.jsonc (#10227)", async () => {
+      mock.method(fs, "existsSync", (candidate) => String(candidate).endsWith("opencode.jsonc"));
+      mock.method(fs, "readFileSync", () => "{ invalid jsonc");
+      const stub = stubFetchOnce(makeCatalogResponse([{ id: "catalog-model", context_length: 8 }]));
+
+      try {
+        const result = await generator.generateConfig("opencode", {
+          baseUrl: "http://localhost:20128",
+          apiKey: "sk-test",
+        });
+
+        assert.strictEqual(result.success, false);
+        assert.match(result.error || "", /invalid.*JSONC|refus/i);
+      } finally {
+        stub.restore();
+        mock.restoreAll();
+      }
+    });
   });
 });
diff --git a/tests/unit/cli-helper/tool-detector-opencode-jsonc-10227.test.ts b/tests/unit/cli-helper/tool-detector-opencode-jsonc-10227.test.ts
new file mode 100644
index 0000000000..f2039e55ef
--- /dev/null
+++ b/tests/unit/cli-helper/tool-detector-opencode-jsonc-10227.test.ts
@@ -0,0 +1,41 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+import * as toolDetector from "../../../src/lib/cli-helper/tool-detector.ts";
+
+test("detectTool reports an existing opencode.jsonc as the real config path (#10227)", async () => {
+  const xdgRoot = fs.mkdtempSync(path.join(os.tmpdir(), "omniroute-detector-jsonc-"));
+  const configDir = path.join(xdgRoot, "opencode");
+  const configPath = path.join(configDir, "opencode.jsonc");
+  const previousXdg = process.env.XDG_CONFIG_HOME;
+
+  toolDetector.__setExecFileImpl(async () => ({ stdout: "v1.0.0\n", stderr: "" }));
+
+  try {
+    fs.mkdirSync(configDir, { recursive: true });
+    fs.writeFileSync(
+      configPath,
+      `{
+  // OpenCode accepts JSONC
+  "provider": {
+    "omniroute": { "options": { "baseURL": "http://localhost:20128/v1" } },
+  },
+}\n`
+    );
+    process.env.XDG_CONFIG_HOME = xdgRoot;
+
+    const result = await toolDetector.detectTool("opencode");
+
+    assert.ok(result !== null);
+    assert.equal(result.configPath, configPath);
+    assert.equal(result.configured, true);
+    assert.match(result.configContents || "", /OpenCode accepts JSONC/);
+  } finally {
+    if (previousXdg === undefined) delete process.env.XDG_CONFIG_HOME;
+    else process.env.XDG_CONFIG_HOME = previousXdg;
+    fs.rmSync(xdgRoot, { recursive: true, force: true });
+  }
+});
diff --git a/tests/unit/cli-runtime-detection.test.ts b/tests/unit/cli-runtime-detection.test.ts
index bd996616f8..1e1e7fedd0 100644
--- a/tests/unit/cli-runtime-detection.test.ts
+++ b/tests/unit/cli-runtime-detection.test.ts
@@ -322,4 +322,38 @@ describe("resolveOpencodeConfigPath — cross-platform", () => {
     );
     assert.equal(result, path.join("D:\\xdg", "opencode", "opencode.json"));
   });
+
+  it("selects an existing opencode.jsonc instead of inventing opencode.json (#10227)", () => {
+    const xdgRoot = createTempDir();
+    const configDir = path.join(xdgRoot, "opencode");
+    const jsoncPath = path.join(configDir, "opencode.jsonc");
+    fs.mkdirSync(configDir, { recursive: true });
+    fs.writeFileSync(jsoncPath, "{\n  // native OpenCode config\n}\n");
+
+    const result = resolveOpencodeConfigPathFn(
+      process.platform,
+      { XDG_CONFIG_HOME: xdgRoot },
+      os.homedir()
+    );
+
+    assert.equal(result, jsoncPath);
+  });
+
+  it("prefers opencode.jsonc when both native filenames exist (#10227)", () => {
+    const xdgRoot = createTempDir();
+    const configDir = path.join(xdgRoot, "opencode");
+    const jsonPath = path.join(configDir, "opencode.json");
+    const jsoncPath = path.join(configDir, "opencode.jsonc");
+    fs.mkdirSync(configDir, { recursive: true });
+    fs.writeFileSync(jsonPath, "{}\n");
+    fs.writeFileSync(jsoncPath, "{}\n");
+
+    const result = resolveOpencodeConfigPathFn(
+      process.platform,
+      { XDG_CONFIG_HOME: xdgRoot },
+      os.homedir()
+    );
+
+    assert.equal(result, jsoncPath);
+  });
 });
diff --git a/tests/unit/cli-tools-apply-opencode-jsonc.test.ts b/tests/unit/cli-tools-apply-opencode-jsonc.test.ts
new file mode 100644
index 0000000000..f530607bc6
--- /dev/null
+++ b/tests/unit/cli-tools-apply-opencode-jsonc.test.ts
@@ -0,0 +1,139 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs/promises";
+import os from "node:os";
+import path from "node:path";
+import { SignJWT } from "jose";
+import { parse } from "jsonc-parser";
+
+const originalDataDir = process.env.DATA_DIR;
+const databaseRoot = await fs.mkdtemp(path.join(os.tmpdir(), "omniroute-apply-jsonc-db-"));
+process.env.DATA_DIR = databaseRoot;
+const applyRoute = await import("../../src/app/api/cli-tools/apply/route.ts");
+
+const originalFetch = globalThis.fetch;
+const originalJwtSecret = process.env.JWT_SECRET;
+const originalApiKeySecret = process.env.API_KEY_SECRET;
+const originalXdg = process.env.XDG_CONFIG_HOME;
+const testRoots = new Set<string>();
+
+async function createAuthCookie(): Promise<string> {
+  process.env.JWT_SECRET = "test-cli-tools-apply-secret";
+  const secret = new TextEncoder().encode(process.env.JWT_SECRET);
+  const token = await new SignJWT({ sub: "test-user" })
+    .setProtectedHeader({ alg: "HS256" })
+    .setIssuedAt()
+    .setExpirationTime("1h")
+    .sign(secret);
+  return `auth_token=${token}`;
+}
+
+async function postApply(): Promise<Response> {
+  const cookie = await createAuthCookie();
+  return applyRoute.POST(
+    new Request("http://localhost/api/cli-tools/apply", {
+      method: "POST",
+      headers: { "Content-Type": "application/json", cookie },
+      body: JSON.stringify({
+        toolId: "opencode",
+        baseUrl: "http://localhost:20128",
+        apiKey: "sk-test",
+        model: "catalog-model",
+      }),
+    })
+  );
+}
+
+test.beforeEach(async () => {
+  const root = await fs.mkdtemp(path.join(os.tmpdir(), "omniroute-apply-jsonc-"));
+  testRoots.add(root);
+  process.env.XDG_CONFIG_HOME = root;
+  process.env.API_KEY_SECRET = "test-secret";
+  globalThis.fetch = async () =>
+    new Response(
+      JSON.stringify({
+        data: [
+          {
+            id: "catalog-model",
+            context_length: 131072,
+            max_output_tokens: 8192,
+          },
+        ],
+      }),
+      { status: 200, headers: { "content-type": "application/json" } }
+    );
+});
+
+test.afterEach(async () => {
+  globalThis.fetch = originalFetch;
+  if (originalJwtSecret === undefined) delete process.env.JWT_SECRET;
+  else process.env.JWT_SECRET = originalJwtSecret;
+  if (originalApiKeySecret === undefined) delete process.env.API_KEY_SECRET;
+  else process.env.API_KEY_SECRET = originalApiKeySecret;
+  if (originalXdg === undefined) delete process.env.XDG_CONFIG_HOME;
+  else process.env.XDG_CONFIG_HOME = originalXdg;
+  for (const root of testRoots) await fs.rm(root, { recursive: true, force: true });
+  testRoots.clear();
+});
+
+test.after(async () => {
+  if (originalDataDir === undefined) delete process.env.DATA_DIR;
+  else process.env.DATA_DIR = originalDataDir;
+  await fs.rm(databaseRoot, { recursive: true, force: true });
+});
+
+test("apply writes back to the selected opencode.jsonc and does not create opencode.json (#10227)", async () => {
+  const configDir = path.join(process.env.XDG_CONFIG_HOME!, "opencode");
+  const jsoncPath = path.join(configDir, "opencode.jsonc");
+  const jsonPath = path.join(configDir, "opencode.json");
+  const original = `{
+  // this comment must survive the merge
+  "$schema": "https://opencode.ai/config.json",
+  "provider": {
+    "custom": {
+      // keep comments inside unrelated providers too
+      "name": "Custom Provider"
+    },
+  },
+}\n`;
+  await fs.mkdir(configDir, { recursive: true });
+  await fs.writeFile(jsoncPath, original, "utf-8");
+
+  const response = await postApply();
+  const body = (await response.json()) as {
+    success?: boolean;
+    configPath?: string;
+    backupPath?: string;
+  };
+
+  assert.equal(response.status, 200);
+  assert.equal(body.success, true);
+  assert.equal(body.configPath, jsoncPath);
+  assert.equal(body.backupPath, path.join(configDir, ".omniroute.bak", "opencode.jsonc.bak"));
+  await assert.rejects(fs.access(jsonPath));
+
+  const updatedText = await fs.readFile(jsoncPath, "utf-8");
+  assert.match(updatedText, /this comment must survive the merge/);
+  assert.match(updatedText, /keep comments inside unrelated providers too/);
+  const updated = parse(updatedText);
+  assert.deepEqual(updated.provider.custom, { name: "Custom Provider" });
+  assert.equal(updated.provider.omniroute.models["catalog-model"].limit.context, 131072);
+  assert.equal(await fs.readFile(body.backupPath!, "utf-8"), original);
+});
+
+test("apply leaves an invalid opencode.jsonc untouched instead of overwriting it (#10227)", async () => {
+  const configDir = path.join(process.env.XDG_CONFIG_HOME!, "opencode");
+  const jsoncPath = path.join(configDir, "opencode.jsonc");
+  const jsonPath = path.join(configDir, "opencode.json");
+  const invalid = "{ invalid jsonc\n";
+  await fs.mkdir(configDir, { recursive: true });
+  await fs.writeFile(jsoncPath, invalid, "utf-8");
+
+  const response = await postApply();
+  const body = (await response.json()) as { error?: string };
+
+  assert.equal(response.status, 400);
+  assert.match(body.error || "", /invalid.*JSONC|refus/i);
+  assert.equal(await fs.readFile(jsoncPath, "utf-8"), invalid);
+  await assert.rejects(fs.access(jsonPath));
+});
diff --git a/tests/unit/cli/setup-opencode.test.ts b/tests/unit/cli/setup-opencode.test.ts
index bf78728144..a25cae6e97 100644
--- a/tests/unit/cli/setup-opencode.test.ts
+++ b/tests/unit/cli/setup-opencode.test.ts
@@ -1,5 +1,6 @@
 import { test } from "node:test";
 import assert from "node:assert/strict";
+import { parse } from "jsonc-parser";
 import {
   postProcessOpencodeConfig,
   resolveOpencodeTarget,
@@ -50,6 +51,31 @@ test("postProcessOpencodeConfig preserves $schema, provider name and npm", () =>
   assert.equal(cfg.provider.omniroute.npm, "@ai-sdk/openai-compatible");
 });
 
+test("postProcessOpencodeConfig preserves JSONC comments outside managed fields", () => {
+  const rawJsonc = `{
+    // top-level user comment
+    "provider": {
+      "custom": {
+        // nested provider comment
+        "npm": "@ai-sdk/custom",
+      },
+      "omniroute": {
+        "options": { "apiKey": "sk-secret-literal" },
+        "models": { "openai/gpt-4o": { "name": "GPT-4o" } },
+      },
+    },
+  }`;
+
+  const { json, modelCount } = postProcessOpencodeConfig(rawJsonc);
+
+  assert.match(json, /\/\/ top-level user comment/);
+  assert.match(json, /\/\/ nested provider comment/);
+  const config = parse(json);
+  assert.equal(config.provider.custom.npm, "@ai-sdk/custom");
+  assert.equal(config.provider.omniroute.options.apiKey, "{env:OMNIROUTE_API_KEY}");
+  assert.equal(modelCount, 1);
+});
+
 test("resolveOpencodeTarget: --remote wins and trailing slashes are trimmed", () => {
   const { baseUrl } = resolveOpencodeTarget({ remote: "http://vps:20128/" });
   assert.equal(baseUrl, "http://vps:20128");
diff --git a/tests/unit/guide-settings-route.test.ts b/tests/unit/guide-settings-route.test.ts
index 8537cbc56c..735240dc1e 100644
--- a/tests/unit/guide-settings-route.test.ts
+++ b/tests/unit/guide-settings-route.test.ts
@@ -11,6 +11,7 @@ const guideSettingsRoute =
 
 const DUMMY_HOME = path.join(os.tmpdir(), "omniroute-guide-settings-test-" + Date.now());
 const OPENCODE_CONFIG_PATH = path.join(DUMMY_HOME, ".config", "opencode", "opencode.json");
+const OPENCODE_JSONC_CONFIG_PATH = path.join(DUMMY_HOME, ".config", "opencode", "opencode.jsonc");
 // cliRuntime.ts hermes entry maps to .config/hermes/config.json (not .hermes/config.yaml)
 const HERMES_CONFIG_PATH = path.join(DUMMY_HOME, ".config", "hermes", "config.json");
 const originalXDG = process.env.XDG_CONFIG_HOME;
@@ -201,3 +202,24 @@ test("guide-settings POST preserves existing OpenCode config fields while only u
     "opencode-go/kimi-k2.6": { name: "Kimi K2.6" },
   });
 });
+
+test("guide-settings POST refuses to overwrite an invalid opencode.jsonc (#10227)", async () => {
+  const invalidJsonc = "{ invalid jsonc\n";
+  await fs.mkdir(path.dirname(OPENCODE_JSONC_CONFIG_PATH), { recursive: true });
+  await fs.writeFile(OPENCODE_JSONC_CONFIG_PATH, invalidJsonc, "utf-8");
+
+  const req = await buildRequest("opencode", {
+    baseUrl: "http://my-omni/v1",
+    apiKey: "sk-123",
+    models: ["cx/gpt-5.6-sol"],
+  });
+  const response = (await guideSettingsRoute.POST(req, {
+    params: { toolId: "opencode" },
+  })) as Response;
+  const data = (await response.json()) as { error?: string };
+
+  assert.equal(response.status, 500);
+  assert.match(data.error || "", /invalid JSONC.*refusing to overwrite/i);
+  assert.equal(await fs.readFile(OPENCODE_JSONC_CONFIG_PATH, "utf-8"), invalidJsonc);
+  await assert.rejects(fs.access(OPENCODE_CONFIG_PATH));
+});
diff --git a/tests/unit/t40-opencode-cli-tools-integration.test.ts b/tests/unit/t40-opencode-cli-tools-integration.test.ts
index feaacf8256..7a7c305bac 100644
--- a/tests/unit/t40-opencode-cli-tools-integration.test.ts
+++ b/tests/unit/t40-opencode-cli-tools-integration.test.ts
@@ -20,7 +20,9 @@ test("T40: OpenCode card documents config paths and --variant usage", () => {
     .join(" ")
     .toLowerCase();
 
-  assert.match(notesText, /\.config\/opencode\/opencode\.json/);
+  assert.match(notesText, /or opencode\.json\b/);
+  assert.match(notesText, /\.config\/opencode\/opencode\.jsonc/);
+  assert.match(notesText, /preferred when present/);
   // #3330: OpenCode uses ~/.config on all platforms (incl. Windows) — the note
   // must no longer point Windows users at %APPDATA%.
   assert.doesNotMatch(notesText, /%appdata%/);