diff --git a/src/features/commands/antigravity-command.ts b/src/features/commands/antigravity-command.ts
index bf7b87705..04145037d 100644
--- a/src/features/commands/antigravity-command.ts
+++ b/src/features/commands/antigravity-command.ts
@@ -155,7 +155,7 @@ export class AntigravityCommand extends ToolCommand {
     // But we DO need to update the body to include the specific workflow header.
     body = `# Workflow: ${trigger}\n\n${body}${turboDirective}`;
 
-    const description = rulesyncFrontmatter.description;
+    const description = rulesyncFrontmatter.description ?? "";
 
     const antigravityFrontmatter: AntigravityCommandFrontmatter = {
       description,
diff --git a/src/features/commands/claudecode-command.ts b/src/features/commands/claudecode-command.ts
index 442370960..8fec41fb2 100644
--- a/src/features/commands/claudecode-command.ts
+++ b/src/features/commands/claudecode-command.ts
@@ -105,7 +105,7 @@ export class ClaudecodeCommand extends ToolCommand {
     const claudecodeFields = rulesyncFrontmatter.claudecode ?? {};
 
     const claudecodeFrontmatter: ClaudecodeCommandFrontmatter = {
-      description: rulesyncFrontmatter.description,
+      description: rulesyncFrontmatter.description ?? "",
       ...claudecodeFields,
     };
 
diff --git a/src/features/commands/copilot-command.ts b/src/features/commands/copilot-command.ts
index 596d60274..b3c1fed7b 100644
--- a/src/features/commands/copilot-command.ts
+++ b/src/features/commands/copilot-command.ts
@@ -120,7 +120,7 @@ export class CopilotCommand extends ToolCommand {
     const copilotFields = rulesyncFrontmatter.copilot ?? {};
 
     const copilotFrontmatter: CopilotCommandFrontmatter = {
-      description: rulesyncFrontmatter.description,
+      description: rulesyncFrontmatter.description ?? "",
       ...copilotFields,
     };
 
diff --git a/src/features/commands/geminicli-command.test.ts b/src/features/commands/geminicli-command.test.ts
index a7b9e17c9..7f1717b25 100644
--- a/src/features/commands/geminicli-command.test.ts
+++ b/src/features/commands/geminicli-command.test.ts
@@ -75,7 +75,7 @@ prompt = "Unclosed string`;
 
       expect(command.getBody()).toBe("This is a test prompt without description.\n");
       expect(command.getFrontmatter()).toEqual({
-        description: "",
+        description: undefined,
         prompt: "This is a test prompt without description.\n",
       });
     });
@@ -134,7 +134,7 @@ prompt = "Unclosed string`;
       });
 
       const frontmatter = command.getFrontmatter() as GeminiCliCommandFrontmatter;
-      expect(frontmatter.description).toBe("");
+      expect(frontmatter.description).toBeUndefined();
       expect(frontmatter.prompt).toBe("This is a test prompt without description.\n");
     });
 
@@ -223,7 +223,7 @@ prompt = "Unclosed string`;
 
       expect(rulesyncCommand.getFrontmatter()).toEqual({
         targets: ["geminicli"],
-        description: "",
+        description: undefined,
       });
     });
   });
diff --git a/src/features/commands/geminicli-command.ts b/src/features/commands/geminicli-command.ts
index 3c61df25f..b0f590086 100644
--- a/src/features/commands/geminicli-command.ts
+++ b/src/features/commands/geminicli-command.ts
@@ -58,7 +58,7 @@ export class GeminiCliCommand extends ToolCommand {
       // Preserve all fields including unknown ones (looseObject passthrough)
       return {
         ...result.data,
-        description: result.data.description || "",
+        description: result.data.description,
       };
     } catch (error) {
       throw new Error(
@@ -84,7 +84,7 @@ export class GeminiCliCommand extends ToolCommand {
 
     const rulesyncFrontmatter: RulesyncCommandFrontmatter = {
       targets: ["geminicli"],
-      description: description ?? "",
+      description,
       // Preserve extra fields in geminicli section (excluding prompt which is the body)
       ...(Object.keys(restFields).length > 0 && { geminicli: restFields }),
     };
@@ -123,8 +123,10 @@ export class GeminiCliCommand extends ToolCommand {
     // Generate proper file content with TOML format
     // Note: TOML format only supports description and prompt fields
     // Extra fields from geminicli section are stored in the object but not serialized to TOML
-    const tomlContent = `description = "${geminiFrontmatter.description}"
-prompt = """
+    const descriptionLine = geminiFrontmatter.description
+      ? `description = "${geminiFrontmatter.description}"\n`
+      : "";
+    const tomlContent = `${descriptionLine}prompt = """
 ${geminiFrontmatter.prompt}
 """`;
 
diff --git a/src/features/commands/opencode-command.ts b/src/features/commands/opencode-command.ts
index 1188825a4..5898ab266 100644
--- a/src/features/commands/opencode-command.ts
+++ b/src/features/commands/opencode-command.ts
@@ -100,7 +100,7 @@ export class OpenCodeCommand extends ToolCommand {
     const opencodeFields = rulesyncFrontmatter.opencode ?? {};
 
     const opencodeFrontmatter: OpenCodeCommandFrontmatter = {
-      description: rulesyncFrontmatter.description,
+      description: rulesyncFrontmatter.description ?? "",
       ...opencodeFields,
     };
 
diff --git a/src/features/commands/roo-command.ts b/src/features/commands/roo-command.ts
index 8a9cb28df..61ccf4266 100644
--- a/src/features/commands/roo-command.ts
+++ b/src/features/commands/roo-command.ts
@@ -104,7 +104,7 @@ export class RooCommand extends ToolCommand {
     const rooFields = rulesyncFrontmatter.roo ?? {};
 
     const rooFrontmatter: RooCommandFrontmatter = {
-      description: rulesyncFrontmatter.description,
+      description: rulesyncFrontmatter.description ?? "",
       ...rooFields,
     };
 
diff --git a/src/features/commands/rulesync-command.test.ts b/src/features/commands/rulesync-command.test.ts
index fe60bd41c..6295e686d 100644
--- a/src/features/commands/rulesync-command.test.ts
+++ b/src/features/commands/rulesync-command.test.ts
@@ -84,19 +84,19 @@ describe("RulesyncCommand", () => {
       expect(() => new RulesyncCommand(paramsWithInvalidData)).toThrow();
     });
 
-    it("should throw error for missing required frontmatter fields", () => {
-      const incompleteFrontmatter = {
+    it("should not throw error for missing optional description", () => {
+      const frontmatterWithoutDescription = {
         targets: ["cursor"],
-        // Missing description
+        // Missing description (now optional)
       };
 
-      const paramsWithIncompleteData: RulesyncCommandParams = {
+      const paramsWithoutDescription: RulesyncCommandParams = {
         ...validParams,
-        frontmatter: incompleteFrontmatter as any,
-        validate: true, // Enable validation
+        frontmatter: frontmatterWithoutDescription as any,
+        validate: true,
       };
 
-      expect(() => new RulesyncCommand(paramsWithIncompleteData)).toThrow();
+      expect(() => new RulesyncCommand(paramsWithoutDescription)).not.toThrow();
     });
 
     it("should generate correct file content from frontmatter and body", () => {
@@ -181,22 +181,21 @@ describe("RulesyncCommand", () => {
       expect(result.error).toBeDefined();
     });
 
-    it("should return failure for missing required fields", () => {
-      const incompleteFrontmatter = {
+    it("should return success for missing optional description", () => {
+      const frontmatterWithoutDescription = {
         targets: ["cursor"],
-        // Missing description
+        // Missing description (now optional)
       };
 
       const command = new RulesyncCommand({
         ...validParams,
-        frontmatter: incompleteFrontmatter as any,
+        frontmatter: frontmatterWithoutDescription as any,
         validate: false,
       });
 
       const result = command.validate();
 
-      expect(result.success).toBe(false);
-      expect(result.error).toBeDefined();
+      expect(result.success).toBe(true);
     });
   });
 
@@ -227,14 +226,14 @@ describe("RulesyncCommand", () => {
       expect(result.success).toBe(false);
     });
 
-    it("should reject missing description", () => {
-      const invalidData = {
+    it("should accept missing description (now optional)", () => {
+      const dataWithoutDescription = {
         targets: ["cursor"],
       };
 
-      const result = RulesyncCommandFrontmatterSchema.safeParse(invalidData);
+      const result = RulesyncCommandFrontmatterSchema.safeParse(dataWithoutDescription);
 
-      expect(result.success).toBe(false);
+      expect(result.success).toBe(true);
     });
 
     it("should reject non-string description", () => {
diff --git a/src/features/commands/rulesync-command.ts b/src/features/commands/rulesync-command.ts
index 4662aaa0d..53a35ca95 100644
--- a/src/features/commands/rulesync-command.ts
+++ b/src/features/commands/rulesync-command.ts
@@ -18,7 +18,7 @@ import { parseFrontmatter, stringifyFrontmatter } from "../../utils/frontmatter.
 // Tool-specific sections (e.g., claudecode:, copilot:) are preserved as additional keys
 export const RulesyncCommandFrontmatterSchema = z.looseObject({
   targets: z._default(RulesyncTargetsSchema, ["*"]),
-  description: z.string(),
+  description: z.optional(z.string()),
 });
 
 // Input type allows targets to be omitted (will use default value)
diff --git a/src/features/commands/simulated-command.ts b/src/features/commands/simulated-command.ts
index 96cdef639..1b5b60b2c 100644
--- a/src/features/commands/simulated-command.ts
+++ b/src/features/commands/simulated-command.ts
@@ -68,7 +68,7 @@ export abstract class SimulatedCommand extends ToolCommand {
     const rulesyncFrontmatter = rulesyncCommand.getFrontmatter();
 
     const claudecodeFrontmatter: SimulatedCommandFrontmatter = {
-      description: rulesyncFrontmatter.description,
+      description: rulesyncFrontmatter.description ?? "",
     };
 
     const body = rulesyncCommand.getBody();
diff --git a/src/features/subagents/codexcli-subagent.ts b/src/features/subagents/codexcli-subagent.ts
index 18244169e..340822ddc 100644
--- a/src/features/subagents/codexcli-subagent.ts
+++ b/src/features/subagents/codexcli-subagent.ts
@@ -87,7 +87,7 @@ export class CodexCliSubagent extends ToolSubagent {
     const rulesyncFrontmatter: RulesyncSubagentFrontmatter = {
       targets: ["codexcli"],
       name,
-      description: description ?? "",
+      description,
       // Only include codexcli section if there are fields
       ...(Object.keys(codexcliSection).length > 0 && { codexcli: codexcliSection }),
     };
diff --git a/src/features/subagents/copilot-subagent.ts b/src/features/subagents/copilot-subagent.ts
index 31e097ef9..87bc3f4c5 100644
--- a/src/features/subagents/copilot-subagent.ts
+++ b/src/features/subagents/copilot-subagent.ts
@@ -120,7 +120,7 @@ export class CopilotSubagent extends ToolSubagent {
 
     const copilotFrontmatter: CopilotSubagentFrontmatter = {
       name: rulesyncFrontmatter.name,
-      description: rulesyncFrontmatter.description,
+      description: rulesyncFrontmatter.description ?? "",
       ...copilotSection,
       ...(mergedTools.length > 0 && { tools: mergedTools }),
     };
diff --git a/src/features/subagents/cursor-subagent.ts b/src/features/subagents/cursor-subagent.ts
index 585363327..1d272260b 100644
--- a/src/features/subagents/cursor-subagent.ts
+++ b/src/features/subagents/cursor-subagent.ts
@@ -97,7 +97,7 @@ export class CursorSubagent extends ToolSubagent {
 
     const cursorFrontmatter: CursorSubagentFrontmatter = {
       name: rulesyncFrontmatter.name,
-      description: rulesyncFrontmatter.description,
+      description: rulesyncFrontmatter.description ?? "",
       ...cursorSection,
     };
 
diff --git a/src/features/subagents/kiro-subagent.ts b/src/features/subagents/kiro-subagent.ts
index 54104ac4f..03cab49a4 100644
--- a/src/features/subagents/kiro-subagent.ts
+++ b/src/features/subagents/kiro-subagent.ts
@@ -94,7 +94,7 @@ export class KiroSubagent extends ToolSubagent {
     const rulesyncFrontmatter: RulesyncSubagentFrontmatter = {
       targets: ["kiro"],
       name,
-      description: description ?? "",
+      description: description ?? undefined,
       // Only include kiro section if there are fields
       ...(Object.keys(kiroSection).length > 0 && { kiro: kiroSection }),
     };
diff --git a/src/features/subagents/opencode-subagent.ts b/src/features/subagents/opencode-subagent.ts
index cac8ba36f..9c50b2d98 100644
--- a/src/features/subagents/opencode-subagent.ts
+++ b/src/features/subagents/opencode-subagent.ts
@@ -99,7 +99,7 @@ export class OpenCodeSubagent extends ToolSubagent {
 
     const opencodeFrontmatter: OpenCodeSubagentFrontmatter = {
       ...opencodeSection,
-      description: rulesyncFrontmatter.description,
+      description: rulesyncFrontmatter.description ?? "",
       mode: "subagent",
       ...(rulesyncFrontmatter.name && { name: rulesyncFrontmatter.name }),
     };
diff --git a/src/features/subagents/rulesync-subagent.test.ts b/src/features/subagents/rulesync-subagent.test.ts
index dff894eff..e47ba42e5 100644
--- a/src/features/subagents/rulesync-subagent.test.ts
+++ b/src/features/subagents/rulesync-subagent.test.ts
@@ -56,7 +56,7 @@ describe("RulesyncSubagentFrontmatterSchema", () => {
     };
 
     expect(() => RulesyncSubagentFrontmatterSchema.parse(missingName)).toThrow();
-    expect(() => RulesyncSubagentFrontmatterSchema.parse(missingDescription)).toThrow();
+    expect(() => RulesyncSubagentFrontmatterSchema.parse(missingDescription)).not.toThrow();
   });
 
   it("should use default targets when omitted", () => {
@@ -149,22 +149,22 @@ describe("RulesyncSubagent", () => {
       expect(subagent.getFrontmatter().claudecode?.model).toBe("opus");
     });
 
-    it("should throw error with invalid frontmatter", () => {
-      const invalidFrontmatter = {
+    it("should not throw error for missing optional description", () => {
+      const frontmatterWithoutDescription = {
         targets: ["*"],
         name: "test-subagent",
-        // missing description
+        // missing description (now optional)
       };
 
       expect(() => {
         const _instance = new RulesyncSubagent({
           baseDir: ".",
           relativeDirPath: RULESYNC_SUBAGENTS_RELATIVE_DIR_PATH,
-          relativeFilePath: "invalid.md",
-          frontmatter: invalidFrontmatter as any,
+          relativeFilePath: "valid.md",
+          frontmatter: frontmatterWithoutDescription as any,
           body: "Test body",
         });
-      }).toThrow();
+      }).not.toThrow();
     });
 
     it("should skip validation when validate=false", () => {
@@ -298,23 +298,22 @@ describe("RulesyncSubagent", () => {
       expect(result.error).toBe(null);
     });
 
-    it("should return error for invalid frontmatter", () => {
+    it("should return success for missing optional description", () => {
       const subagent = new RulesyncSubagent({
         baseDir: ".",
         relativeDirPath: RULESYNC_SUBAGENTS_RELATIVE_DIR_PATH,
-        relativeFilePath: "invalid-validate.md",
+        relativeFilePath: "valid-validate.md",
         frontmatter: {
           targets: ["*"],
-          name: "invalid-subagent",
-          // missing description
+          name: "valid-subagent",
+          // missing description (now optional)
         } as any,
-        body: "Invalid body",
-        validate: false, // Skip validation in constructor for testing
+        body: "Valid body",
+        validate: false,
       });
 
       const result = subagent.validate();
-      expect(result.success).toBe(false);
-      expect(result.error).toBeInstanceOf(Error);
+      expect(result.success).toBe(true);
     });
   });
 
@@ -412,8 +411,7 @@ Nested content.`;
       const filePath = join(subagentsDir, "test-fromfile-invalid.md");
       const fileContent = `---
 targets: ["*"]
-name: invalid-subagent
-# missing description
+# missing name (required field)
 ---
 Invalid content.`;
 
diff --git a/src/features/subagents/rulesync-subagent.ts b/src/features/subagents/rulesync-subagent.ts
index a1bdc661f..d0ed08141 100644
--- a/src/features/subagents/rulesync-subagent.ts
+++ b/src/features/subagents/rulesync-subagent.ts
@@ -19,7 +19,7 @@ import { parseFrontmatter, stringifyFrontmatter } from "../../utils/frontmatter.
 export const RulesyncSubagentFrontmatterSchema = z.looseObject({
   targets: z._default(RulesyncTargetsSchema, ["*"]),
   name: z.string(),
-  description: z.string(),
+  description: z.optional(z.string()),
 });
 
 // Input type allows targets to be omitted (will use default value)
diff --git a/src/features/subagents/simulated-subagent.ts b/src/features/subagents/simulated-subagent.ts
index ac304266a..09eb70ef8 100644
--- a/src/features/subagents/simulated-subagent.ts
+++ b/src/features/subagents/simulated-subagent.ts
@@ -70,7 +70,7 @@ export abstract class SimulatedSubagent extends ToolSubagent {
 
     const simulatedFrontmatter: SimulatedSubagentFrontmatter = {
       name: rulesyncFrontmatter.name,
-      description: rulesyncFrontmatter.description,
+      description: rulesyncFrontmatter.description ?? "",
     };
 
     const body = rulesyncSubagent.getBody();