fix: unify $status to const-only, drop enum support (#123)

- Validator: hasStatusConst/getConstStatuses replace enum checks
- enum in $status is now rejected with clear error message
- All docs/examples/tests migrated from enum to const/oneOf
- bootstrap hello.yaml updated

Fixes #123

packages/cli/src/__tests__/current-role.test.ts

@@ -28,9 +28,13 @@ roles:
       $status: "ready"
     frontmatter:
       type: object
-      required: ["$status"]
-      properties:
-        $status: { type: string, enum: ["ready", "not-ready"] }
+      oneOf:
+        - properties:
+            $status: { const: "ready" }
+          required: ["$status"]
+        - properties:
+            $status: { const: "not-ready" }
+          required: ["$status"]
   roleB:
     description: Second role
     goal: Do B
@@ -42,7 +46,7 @@ roles:
       type: object
       required: ["$status"]
       properties:
-        $status: { type: string, enum: ["done"] }
+        $status: { const: "done" }
 graph:
   $START:
     new:
@@ -82,9 +86,13 @@ roles:
       $status: "pass"
     frontmatter:
       type: object
-      required: ["$status"]
-      properties:
-        $status: { type: string, enum: ["pass", "fail"] }
+      oneOf:
+        - properties:
+            $status: { const: "pass" }
+          required: ["$status"]
+        - properties:
+            $status: { const: "fail" }
+          required: ["$status"]
   roleB:
     description: Pass role
     goal: Do B
@@ -96,7 +104,7 @@ roles:
       type: object
       required: ["$status"]
       properties:
-        $status: { type: string, enum: ["done"] }
+        $status: { const: "done" }
   roleC:
     description: Fail role
     goal: Do C
@@ -108,7 +116,7 @@ roles:
       type: object
       required: ["$status"]
       properties:
-        $status: { type: string, enum: ["done"] }
+        $status: { const: "done" }
 graph:
   $START:
     new:
@@ -155,7 +163,7 @@ roles:
       type: object
       required: ["$status"]
       properties:
-        $status: { type: string, enum: ["done"] }
+        $status: { const: "done" }
 graph:
   $START:
     new:

packages/cli/src/__tests__/thread-location.test.ts

@@ -54,7 +54,7 @@ roles:
       type: object
       required: ["$status"]
       properties:
-        $status: { type: string, enum: ["ready"] }
+        $status: { const: "ready" }
 graph:
   $START:
     new:
@@ -114,7 +114,7 @@ roles:
       type: object
       required: ["$status"]
       properties:
-        $status: { type: string, enum: ["ready"] }
+        $status: { const: "ready" }
 graph:
   $START:
     new:
@@ -161,7 +161,7 @@ roles:
       type: object
       required: ["$status"]
       properties:
-        $status: { type: string, enum: ["ready"] }
+        $status: { const: "ready" }
 graph:
   $START:
     new:

packages/cli/src/__tests__/thread-show-status.test.ts

@@ -31,7 +31,7 @@ roles:
       type: object
       required: ["$status"]
       properties:
-        $status: { type: string, enum: ["ready"] }
+        $status: { const: "ready" }
 graph:
   $START:
     new:

packages/cli/src/__tests__/thread-start-cwd-cli.test.ts

@@ -54,7 +54,7 @@ roles:
       type: object
       required: ["$status"]
       properties:
-        $status: { type: string, enum: ["ready"] }
+        $status: { const: "ready" }
 graph:
   $START:
     new:

packages/cli/src/__tests__/validate-semantic.test.ts

@@ -17,7 +17,7 @@ function makeWorkflow(overrides?: Partial<WorkflowPayload>): WorkflowPayload {
         frontmatter: {
           type: "object",
           properties: {
-            $status: { enum: ["done"] },
+            $status: { const: "done" },
             plan: { type: "string" },
           },
           required: ["$status", "plan"],
@@ -85,7 +85,7 @@ describe("Suite 1: Role Reference Integrity", () => {
       output: "None",
       frontmatter: {
         type: "object",
-        properties: { $status: { enum: ["done"] } },
+        properties: { $status: { const: "done" } },
         required: ["$status"],
       } as unknown as string,
     };
@@ -187,7 +187,7 @@ describe("Suite 2: Graph Structure", () => {
       output: "Isolated",
       frontmatter: {
         type: "object",
-        properties: { $status: { enum: ["done"] } },
+        properties: { $status: { const: "done" } },
         required: ["$status"],
       } as unknown as string,
     };
@@ -272,8 +272,8 @@ describe("Suite 3: Status-Edge Consistency", () => {
   });
 });
 
-describe("Suite 3b: Enum-Based Multi-Exit", () => {
-  test("3b.1 enum multi-exit passes with matching graph keys", () => {
+describe("Suite 3b: Enum-Based $status is Rejected", () => {
+  test("3b.1 enum multi-exit is rejected (must use oneOf + const)", () => {
     const wf = makeWorkflow();
     wf.roles.reviewer = {
       ...wf.roles.reviewer,
@@ -291,52 +291,10 @@ describe("Suite 3b: Enum-Based Multi-Exit", () => {
       rejected: { role: "writer", prompt: "Fix: {{{comments}}}", location: null },
     };
     const errors = validateWorkflow(wf);
-    expect(errors).toEqual([]);
+    expect(errors.some((e) => e.includes("must define") && e.includes("const"))).toBe(true);
   });
 
-  test("3b.2 enum multi-exit with extra graph key", () => {
-    const wf = makeWorkflow();
-    wf.roles.reviewer = {
-      ...wf.roles.reviewer,
-      frontmatter: {
-        type: "object",
-        properties: {
-          $status: { enum: ["approved", "rejected"] },
-          comments: { type: "string" },
-        },
-        required: ["$status", "comments"],
-      } as unknown as string,
-    };
-    wf.graph.reviewer = {
-      approved: { role: "$END", prompt: "Done", location: null },
-      rejected: { role: "writer", prompt: "Fix", location: null },
-      timeout: { role: "$END", prompt: "Timed out", location: null },
-    };
-    const errors = validateWorkflow(wf);
-    expect(errors.some((e) => e.includes("extra status keys: timeout"))).toBe(true);
-  });
-
-  test("3b.3 enum multi-exit with missing graph key", () => {
-    const wf = makeWorkflow();
-    wf.roles.reviewer = {
-      ...wf.roles.reviewer,
-      frontmatter: {
-        type: "object",
-        properties: {
-          $status: { enum: ["approved", "rejected"] },
-          comments: { type: "string" },
-        },
-        required: ["$status", "comments"],
-      } as unknown as string,
-    };
-    wf.graph.reviewer = {
-      approved: { role: "$END", prompt: "Done", location: null },
-    };
-    const errors = validateWorkflow(wf);
-    expect(errors.some((e) => e.includes("missing status keys: rejected"))).toBe(true);
-  });
-
-  test("3b.4 enum with single explicit value passes", () => {
+  test("3b.2 enum single-exit is rejected (must use const)", () => {
     const wf = makeWorkflow();
     wf.roles.writer = {
       ...wf.roles.writer,
@@ -351,28 +309,71 @@ describe("Suite 3b: Enum-Based Multi-Exit", () => {
     };
     wf.graph.writer = { ready: { role: "reviewer", prompt: "Review: {{{plan}}}", location: null } };
     const errors = validateWorkflow(wf);
-    expect(errors).toEqual([]);
+    expect(errors.some((e) => e.includes("must define") && e.includes("const"))).toBe(true);
   });
+});
 
-  test("3b.5 enum multi-exit mustache var not in frontmatter", () => {
+describe("Suite 3c: Const-Based Flat Schema", () => {
+  test("3c.1 flat schema with const $status passes validation", () => {
     const wf = makeWorkflow();
-    wf.roles.reviewer = {
-      ...wf.roles.reviewer,
+    wf.roles.writer = {
+      ...wf.roles.writer,
       frontmatter: {
         type: "object",
         properties: {
-          $status: { enum: ["approved", "rejected"] },
-          comments: { type: "string" },
+          $status: { const: "done" },
+          plan: { type: "string" },
         },
-        required: ["$status", "comments"],
+        required: ["$status", "plan"],
       } as unknown as string,
     };
-    wf.graph.reviewer = {
-      approved: { role: "$END", prompt: "Done: {{{nonexistent}}}", location: null },
-      rejected: { role: "writer", prompt: "Fix: {{{comments}}}", location: null },
+    const errors = validateWorkflow(wf);
+    expect(errors).toEqual([]);
+  });
+
+  test("3c.2 flat schema with const $status detects extra graph key", () => {
+    const wf = makeWorkflow();
+    wf.roles.writer = {
+      ...wf.roles.writer,
+      frontmatter: {
+        type: "object",
+        properties: {
+          $status: { const: "done" },
+          plan: { type: "string" },
+        },
+        required: ["$status", "plan"],
+      } as unknown as string,
+    };
+    wf.graph.writer = {
+      done: { role: "reviewer", prompt: "Review.", location: null },
+      extra: { role: "$END", prompt: "Nope.", location: null },
     };
     const errors = validateWorkflow(wf);
-    expect(errors.some((e) => e.includes("nonexistent") && e.includes("not found"))).toBe(true);
+    expect(errors.some((e) => e.includes("extra status keys") && e.includes("extra"))).toBe(true);
+  });
+
+  test("3c.3 flat schema with const $status validates mustache vars", () => {
+    const wf = makeWorkflow();
+    wf.roles.writer = {
+      ...wf.roles.writer,
+      frontmatter: {
+        type: "object",
+        properties: {
+          $status: { const: "done" },
+          plan: { type: "string" },
+        },
+        required: ["$status", "plan"],
+      } as unknown as string,
+    };
+    wf.graph.writer = {
+      done: { role: "reviewer", prompt: "Review: {{{nonexistent}}}", location: null },
+    };
+    const errors = validateWorkflow(wf);
+    expect(
+      errors.some(
+        (e) => e.includes('prompt variable "nonexistent"') && e.includes('role "writer"'),
+      ),
+    ).toBe(true);
   });
 });
 
@@ -480,7 +481,7 @@ describe("Suite 6: Multiple Errors Collection", () => {
       output: "None",
       frontmatter: {
         type: "object",
-        properties: { $status: { enum: ["done"] } },
+        properties: { $status: { const: "done" } },
         required: ["$status"],
       } as unknown as string,
     };

packages/cli/src/__tests__/workflow-resolution.test.ts

@@ -31,7 +31,7 @@ function makeMinimalPayload(name: string, description: string): WorkflowPayload
         frontmatter: {
           type: "object",
           properties: {
-            $status: { type: "string", enum: ["done"] },
+            $status: { const: "done" },
           },
           required: ["$status"],
         } as unknown as CasRef,

packages/cli/src/commands/prompt.ts

@@ -219,7 +219,7 @@ roles:
     frontmatter:
       type: object
       properties:
-        $status: { enum: [done] }
+        $status: { const: done }
         message: { type: string }
       required: [$status, message]
 graph:

packages/cli/src/validate-semantic.ts

@@ -24,22 +24,22 @@ function isOneOfSchema(fm: unknown): fm is SchemaObj & { oneOf: SchemaObj[] } {
   return Array.isArray(obj.oneOf);
 }
 
-/** Check if a frontmatter schema declares "$status" as an enum (the required form for user roles). */
-function hasStatusEnum(fm: unknown): boolean {
+/** Check if a frontmatter schema declares "$status" as const (flat schema form). */
+function hasStatusConst(fm: unknown): boolean {
   if (typeof fm !== "object" || fm === null) return false;
   const obj = fm as SchemaObj;
   const props = obj.properties as Record<string, SchemaObj> | undefined;
   if (!props?.$status) return false;
-  return Array.isArray(props.$status.enum);
+  return typeof props.$status.const === "string";
 }
 
-/** Extract status values from an enum-based $status field. */
-function getEnumStatuses(fm: SchemaObj): string[] {
+/** Extract status values from a const-based $status field. */
+function getConstStatuses(fm: SchemaObj): string[] {
   const props = fm.properties as Record<string, SchemaObj> | undefined;
   if (!props?.$status) return [];
   const statusDef = props.$status;
-  if (!Array.isArray(statusDef.enum)) return [];
-  return statusDef.enum as string[];
+  if (typeof statusDef.const === "string") return [statusDef.const];
+  return [];
 }
 
 /** Get property names from a schema object. */
@@ -248,21 +248,21 @@ function checkRoleConsistency(payload: WorkflowPayload, errors: string[]): void
       checkOneOfDiscriminant(roleName, variants, statuses, errors);
       checkStatusEdges(roleName, graphKeys, new Set(statuses), errors);
       checkMultiExitMustache(roleName, graphEntry, variants, errors);
-    } else if (hasStatusEnum(fm)) {
-      const statuses = getEnumStatuses(fm as SchemaObj);
+    } else if (hasStatusConst(fm)) {
+      const statuses = getConstStatuses(fm as SchemaObj);
       checkStatusEdges(roleName, graphKeys, new Set(statuses), errors);
-      // For enum-based schemas, mustache vars come from the flat properties
-      checkEnumMustache(roleName, graphEntry, fm as SchemaObj, errors);
+      // For const-based flat schemas, mustache vars come from the flat properties
+      checkFlatMustache(roleName, graphEntry, fm as SchemaObj, errors);
     } else {
       errors.push(
-        `role "${roleName}" must define "$status" as an enum (or oneOf const) in frontmatter`,
+        `role "${roleName}" must define "$status" as const (or oneOf with const) in frontmatter`,
       );
     }
   }
 }
 
 /** Check mustache vars in all edge prompts against flat schema properties. */
-function checkEnumMustache(
+function checkFlatMustache(
   roleName: string,
   graphEntry: Record<string, { role: string; prompt: string }>,
   fm: SchemaObj,

packages/util-agent/__tests__/build-output-format-instruction.test.ts

@@ -143,7 +143,7 @@ describe("buildOutputFormatInstruction", () => {
         {
           type: "object",
           properties: {
-            $status: { type: "string", enum: ["approved"] },
+            $status: { const: "approved" },
             branch: { type: "string" },
           },
           required: ["$status"],
@@ -151,7 +151,7 @@ describe("buildOutputFormatInstruction", () => {
         {
           type: "object",
           properties: {
-            $status: { type: "string", enum: ["rejected"] },
+            $status: { const: "rejected" },
             comments: { type: "string" },
           },
           required: ["$status"],

packages/util/src/workflow-authoring-reference.ts

@@ -90,23 +90,21 @@ frontmatter:
       required: [$status, error]
 \`\`\`
 
-**Single-exit (flat schema)** — use \`enum\` (not \`const\`):
+**Single-exit (flat schema)** — same syntax, just no \`oneOf\` wrapper:
 
 \`\`\`yaml
 frontmatter:
   type: object
   properties:
-    $status:
-      type: string
-      enum: [done]
+    $status: { const: "done" }
     summary: { type: string }
   required: [$status, summary]
 \`\`\`
 
 **Important rules:**
 - \`type: object\` is **required** at the top level of frontmatter (both flat and oneOf)
-- In flat schemas, \`$status\` must use \`enum: [value]\`, NOT \`const: "value"\` — the validator rejects \`const\` outside of \`oneOf\` variants
-- In \`oneOf\` schemas, each variant's \`$status\` must use \`const: "value"\`
+- \`$status\` always uses \`const: "value"\` — simple and consistent
+- \`enum\` is **not supported** for \`$status\` — the validator will reject it
 
 ### Custom Fields