diff --git a/changelog.d/fixes/13022-desktop-exe-malformed-skill-tool-schemas.md b/changelog.d/fixes/13022-desktop-exe-malformed-skill-tool-schemas.md
new file mode 100644
index 0000000000..8765865032
--- /dev/null
+++ b/changelog.d/fixes/13022-desktop-exe-malformed-skill-tool-schemas.md
@@ -0,0 +1 @@
+- **fix(skills):** repair nested malformed skill-tool schemas (bare property maps, boolean `required: true`) for OpenAI-compatible providers, not just the schema root (#13022) — thanks @ftevxk
diff --git a/src/lib/skills/injection.ts b/src/lib/skills/injection.ts
index 881a039189..951a65d102 100644
--- a/src/lib/skills/injection.ts
+++ b/src/lib/skills/injection.ts
@@ -51,6 +51,133 @@ export function decodeSkillToolName(toolName: string): string {
   }
 }
 
+// Depth guard mirroring open-sse/services/toolSchemaSanitizer.ts's
+// MAX_RECURSION_DEPTH, so a pathological/cyclic-looking nested schema
+// submitted by a custom skill (POST /api/skills accepts any z.record shape)
+// cannot blow the stack.
+const MAX_SCHEMA_REPAIR_DEPTH = 32;
+
+// JSON Schema keywords whose *value* is itself a schema node/map, not a
+// user-declared property — recursing into their children must not treat the
+// container itself as a "bare property map" candidate. Mirrors
+// open-sse/translator/helpers/geminiHelper.ts's SCHEMA_MAP_KEYS for the
+// Gemini-only normalizeMalformedSchemaObjects this mirrors (#12269).
+const SCHEMA_MAP_KEYS = new Set(["properties", "$defs", "definitions", "patternProperties"]);
+
+const SCHEMA_NODE_KEYS = new Set([
+  "additionalProperties",
+  "additionalItems",
+  "contains",
+  "default",
+  "dependencies",
+  "discriminator",
+  "else",
+  "example",
+  "examples",
+  "if",
+  "patternProperties",
+  "propertyNames",
+  "then",
+]);
+
+function isSchemaNode(record: Record<string, unknown>): boolean {
+  if (Object.keys(record).some((key) => key.startsWith("x-") || SCHEMA_NODE_KEYS.has(key))) {
+    return true;
+  }
+  if (typeof record.type === "string" || Array.isArray(record.type)) return true;
+  if (record.properties !== undefined || Array.isArray(record.required)) return true;
+  if (record.items !== undefined) return true;
+  if (record.anyOf !== undefined || record.oneOf !== undefined || record.allOf !== undefined) {
+    return true;
+  }
+  return record.$ref !== undefined || record.enum !== undefined || record.const !== undefined;
+}
+
+function isBarePropertyMap(record: Record<string, unknown>): boolean {
+  const keys = Object.keys(record);
+  if (keys.length === 0 || isSchemaNode(record)) return false;
+  return keys.every((key) => {
+    const value = record[key];
+    return Boolean(value) && typeof value === "object" && !Array.isArray(value);
+  });
+}
+
+// Strips a scalar (non-array) `required` off every property of `record` and,
+// only when it was `true`, promotes the property's key onto the parent
+// schema's own `required` array (created if absent, deduped if present).
+function promoteBooleanRequired(record: Record<string, unknown>): void {
+  const properties = record.properties;
+  if (!properties || typeof properties !== "object" || Array.isArray(properties)) return;
+
+  const required = Array.isArray(record.required)
+    ? record.required.filter((field): field is string => typeof field === "string")
+    : [];
+
+  for (const [name, schema] of Object.entries(properties as Record<string, unknown>)) {
+    if (!schema || typeof schema !== "object" || Array.isArray(schema)) continue;
+    const child = schema as Record<string, unknown>;
+    if (child.required === true && !required.includes(name)) {
+      required.push(name);
+    }
+    if ("required" in child && !Array.isArray(child.required)) {
+      delete child.required;
+    }
+  }
+
+  if (required.length > 0) {
+    record.required = required;
+  } else if (!Array.isArray(record.required)) {
+    delete record.required;
+  }
+}
+
+// Repairs the two malformed-schema shapes strict JSON Schema validators
+// (agnes/nvidia/DeepSeek and other OpenAI-compatible upstreams) reject,
+// recursing into every nested level of a skill's declared input schema —
+// not just the root map #11881 already handled:
+//   1. A bare property map with no `type`/`properties` wrapper (e.g.
+//      `{ opts: { limit: { type: "number" } } }`) is lifted into
+//      `{ type: "object", properties: {...} }`, bottom-up so nested bare
+//      maps are fixed before their parent is inspected.
+//   2. A scalar `required: true` on a property is stripped and promoted onto
+//      the parent's `required` array instead.
+// Mirrors open-sse/translator/helpers/geminiHelper.ts's
+// normalizeMalformedSchemaObjects (itself modeled on CLIProxyAPI's function
+// of the same name), which already does this for the Gemini/Antigravity
+// request-translation path (#12269) — this is the skill-injection-path
+// equivalent, additive and independent from that implementation.
+function repairMalformedSchema(node: unknown, parentKey?: string, depth = 0): void {
+  if (!node || typeof node !== "object" || depth > MAX_SCHEMA_REPAIR_DEPTH) return;
+
+  if (Array.isArray(node)) {
+    for (const item of node) {
+      repairMalformedSchema(item, parentKey, depth + 1);
+    }
+    return;
+  }
+
+  const record = node as Record<string, unknown>;
+
+  for (const [key, value] of Object.entries(record)) {
+    if (value && typeof value === "object") {
+      repairMalformedSchema(value, key, depth + 1);
+    }
+  }
+
+  if (parentKey === undefined || !SCHEMA_MAP_KEYS.has(parentKey)) {
+    if (isBarePropertyMap(record)) {
+      const props = { ...record };
+      for (const key of Object.keys(record)) {
+        delete record[key];
+      }
+      record.type = "object";
+      record.properties = props;
+    }
+  }
+
+  promoteBooleanRequired(record);
+}
+
 // Skills store a flat JSON Schema record ({ "text": { "type": "string" } }),
 // but Gemini (function_declarations[].parameters) and Anthropic
 // (input_schema) require a full object schema with a properties wrapper.
@@ -60,23 +187,30 @@ function normalizeInputSchema(input: Record<string, unknown>): Record<string, un
   if (typeof input !== "object" || input === null || Array.isArray(input)) {
     return input ?? {};
   }
+
+  let root: Record<string, unknown>;
   if (typeof input.type === "string") {
-    return input;
+    // Already a full object schema (#11881's root case doesn't apply) — but
+    // it may still carry the deeper #13022 malformations (nested bare
+    // property maps, per-property boolean `required`) inside `properties`,
+    // so still recurse; just skip the root-level string-shorthand expansion.
+    root = { ...input };
+  } else {
+    // Some builtin skills declare property types in shorthand ("content":
+    // "string" instead of "content": { "type": "string" }). Strict schema
+    // validators — Zhipu GLM served through opencode-go (upstream error [1210]
+    // "Invalid API parameter") — reject the shorthand as malformed JSON Schema,
+    // which 400s every request the skill tools are injected into. Expand string
+    // values to { type: value }; non-string values pass through untouched.
+    const properties: Record<string, unknown> = {};
+    for (const [key, value] of Object.entries(input)) {
+      properties[key] = typeof value === "string" ? { type: value } : value;
+    }
+    root = { type: "object", properties };
   }
-  // Some builtin skills declare property types in shorthand ("content":
-  // "string" instead of "content": { "type": "string" }). Strict schema
-  // validators — Zhipu GLM served through opencode-go (upstream error [1210]
-  // "Invalid API parameter") — reject the shorthand as malformed JSON Schema,
-  // which 400s every request the skill tools are injected into. Expand string
-  // values to { type: value }; non-string values pass through untouched.
-  const properties: Record<string, unknown> = {};
-  for (const [key, value] of Object.entries(input)) {
-    properties[key] = typeof value === "string" ? { type: value } : value;
-  }
-  return {
-    type: "object",
-    properties,
-  };
+
+  repairMalformedSchema(root);
+  return root;
 }
 
 function skillToOpenAI(skill: Skill): OpenAITool {
diff --git a/tests/unit/issue-13022-nested-skill-schema.test.ts b/tests/unit/issue-13022-nested-skill-schema.test.ts
new file mode 100644
index 0000000000..e50571eb84
--- /dev/null
+++ b/tests/unit/issue-13022-nested-skill-schema.test.ts
@@ -0,0 +1,88 @@
+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";
+
+const TEST_DATA_DIR = fs.mkdtempSync(path.join(os.tmpdir(), "omniroute-issue-13022-"));
+process.env.DATA_DIR = TEST_DATA_DIR;
+
+const coreDb = await import("../../src/lib/db/core.ts");
+const { skillRegistry } = await import("../../src/lib/skills/registry.ts");
+const { injectSkills } = await import("../../src/lib/skills/injection.ts");
+
+function resetRegistryState() {
+  skillRegistry["registeredSkills"].clear();
+  skillRegistry["versionCache"].clear();
+}
+
+test.after(() => {
+  resetRegistryState();
+  coreDb.resetDbInstance();
+  fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true, maxRetries: 5, retryDelay: 100 });
+});
+
+test("#13022: nested bare property map survives skill injection for OpenAI-format providers (agnes/nvidia/DeepSeek)", async () => {
+  await skillRegistry.register({
+    name: "nested-tool",
+    version: "1.0.0",
+    description: "a skill with a nested bare property map, like a local/skillssh author would ship",
+    schema: { input: { query: "string", opts: { limit: { type: "number" } } }, output: {} },
+    handler: "nested-tool-handler",
+    enabled: true,
+    apiKeyId: "issue-13022-key",
+  });
+
+  const tools = injectSkills({ provider: "openai", apiKeyId: "issue-13022-key" }) as Array<{
+    function: { parameters: Record<string, unknown> };
+  }>;
+  assert.equal(tools.length, 1);
+
+  const parameters = tools[0].function.parameters;
+  const properties = parameters.properties as Record<string, Record<string, unknown>>;
+
+  assert.equal(
+    properties.query.type,
+    "string",
+    "#11881 root shorthand expansion should still work"
+  );
+
+  const opts = properties.opts;
+  assert.equal(
+    opts.type,
+    "object",
+    "BUG #13022: nested bare property map missing type:object wrapper"
+  );
+});
+
+test("#13022: per-property boolean required:true survives skill injection for OpenAI-format providers", async () => {
+  await skillRegistry.register({
+    name: "required-bool-tool",
+    version: "1.0.0",
+    description:
+      "a skill declaring required as a boolean on the property, not an array on the schema",
+    schema: { input: { content: { type: "string", required: true } }, output: {} },
+    handler: "required-bool-handler",
+    enabled: true,
+    apiKeyId: "issue-13022-key-2",
+  });
+
+  const tools = injectSkills({ provider: "openai", apiKeyId: "issue-13022-key-2" }) as Array<{
+    function: { parameters: Record<string, unknown> };
+  }>;
+  assert.equal(tools.length, 1);
+
+  const parameters = tools[0].function.parameters;
+  const properties = parameters.properties as Record<string, Record<string, unknown>>;
+
+  assert.equal(
+    "required" in properties.content,
+    false,
+    "BUG #13022: boolean required:true survived on the property"
+  );
+  assert.deepEqual(
+    parameters.required,
+    ["content"],
+    "BUG #13022: boolean required:true was not promoted"
+  );
+});