refactor: remove systemPrompt, make four-phase fields required

Breaking change per review:
- Remove systemPrompt from RoleDefinition entirely
- identity/prepare/execute/report are now required (string, not nullable)
- Remove all legacy fallback logic in buildRolePrompt
- Simplify validate.ts, workflow.ts materialize
- Migrate all test fixtures and example workflows

Refs #359

examples/solve-issue.yaml

@@ -3,7 +3,10 @@ description: "End-to-end issue resolution"
 roles:
   planner:
     description: "Creates implementation plan"
-    systemPrompt: "You are a planning agent. Analyze the issue and create a step-by-step plan."
+    identity: "You are a planning agent. You analyze issues and create step-by-step plans."
+    prepare: "Read the issue description and any linked context carefully."
+    execute: "Analyze the issue and create a detailed, actionable implementation plan."
+    report: "Output the plan summary and list of concrete steps."
     outputSchema:
       type: object
       properties:
@@ -16,7 +19,10 @@ roles:
       required: [plan, steps]
   developer:
     description: "Implements code changes"
-    systemPrompt: "You are a developer agent. Implement the plan."
+    identity: "You are a developer agent. You implement code changes according to plans."
+    prepare: "Load coding tools and review the project structure and conventions."
+    execute: "Implement the plan. Write code, tests, and ensure existing tests pass."
+    report: "List all files changed and provide a summary of the implementation."
     outputSchema:
       type: object
       properties:
@@ -29,7 +35,10 @@ roles:
       required: [filesChanged, summary]
   reviewer:
     description: "Reviews code changes"
-    systemPrompt: "You are a code reviewer. Review the implementation."
+    identity: "You are a code reviewer. You review implementations for correctness and quality."
+    prepare: "Review the project's coding standards and conventions."
+    execute: "Review the implementation against the plan. Check for bugs, edge cases, and style."
+    report: "Approve or reject with detailed comments explaining your decision."
     outputSchema:
       type: object
       properties:

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

@@ -211,7 +211,10 @@ describe("cmdThreadRead ### Content section", () => {
       roles: {
         writer: {
           description: "Write",
-          systemPrompt: "You are a writer.",
+          identity: "You are a writer.",
+          prepare: "",
+          execute: "Write content as requested.",
+          report: "Summarize what was written.",
           outputSchema: "placeholder00" as CasRef,
         },
       },

packages/cli-workflow/src/commands/thread.ts

@@ -500,7 +500,7 @@ function formatThreadReadMarkdown(options: {
     ];
     const roleDef = workflow.roles[item.payload.role];
     if (roleDef) {
-      const prompt = roleDef.identity ?? roleDef.systemPrompt ?? "";
+      const prompt = roleDef.identity;
       stepLines.push("", "### Prompt", "", prompt);
     }
     if (item.payload.detail) {

packages/cli-workflow/src/commands/workflow.ts

@@ -67,22 +67,14 @@ async function materializeWorkflowPayload(
       `${raw.name}.${roleName}`,
       role.outputSchema,
     );
-    const roleDef: RoleDefinition = {
+    roles[roleName] = {
       description: role.description,
-      systemPrompt: role.systemPrompt ?? null,
-      identity: role.identity ?? null,
-      prepare: role.prepare ?? null,
-      execute: role.execute ?? null,
-      report: role.report ?? null,
+      identity: role.identity,
+      prepare: role.prepare,
+      execute: role.execute,
+      report: role.report,
       outputSchema,
     };
-    // Strip null fields so CAS payload stays lean and schema-valid
-    for (const key of ["systemPrompt", "identity", "prepare", "execute", "report"] as const) {
-      if (roleDef[key] === null) {
-        delete (roleDef as Record<string, unknown>)[key];
-      }
-    }
-    roles[roleName] = roleDef;
   }
   return {
     name: raw.name,

packages/cli-workflow/src/validate.ts

@@ -16,17 +16,14 @@ function isRoleDefinition(value: unknown): boolean {
   }
   const outputSchema = value.outputSchema;
   const schemaOk = isRecord(outputSchema) && typeof outputSchema.type === "string";
-  const hasSystemPrompt =
-    value.systemPrompt === undefined || value.systemPrompt === null || typeof value.systemPrompt === "string";
-  const hasIdentity =
-    value.identity === undefined || value.identity === null || typeof value.identity === "string";
-  const hasPrepare =
-    value.prepare === undefined || value.prepare === null || typeof value.prepare === "string";
-  const hasExecute =
-    value.execute === undefined || value.execute === null || typeof value.execute === "string";
-  const hasReport =
-    value.report === undefined || value.report === null || typeof value.report === "string";
-  return typeof value.description === "string" && hasSystemPrompt && hasIdentity && hasPrepare && hasExecute && hasReport && schemaOk;
+  return (
+    typeof value.description === "string" &&
+    typeof value.identity === "string" &&
+    typeof value.prepare === "string" &&
+    typeof value.execute === "string" &&
+    typeof value.report === "string" &&
+    schemaOk
+  );
 }
 
 function isConditionDefinition(value: unknown): boolean {

packages/workflow-agent-kit/__tests__/build-role-prompt.test.ts

@@ -3,10 +3,9 @@ import type { RoleDefinition } from "@uncaged/workflow-protocol";
 import { buildRolePrompt } from "../src/build-role-prompt.js";
 
 describe("buildRolePrompt", () => {
-  test("four-phase: all fields present", () => {
+  test("all fields present", () => {
     const role: RoleDefinition = {
       description: "A coder",
-      systemPrompt: "legacy prompt",
       identity: "You are a senior developer.",
       prepare: "Load cursor-agent skill.",
       execute: "Implement the feature.",
@@ -22,40 +21,15 @@ describe("buildRolePrompt", () => {
     expect(result).toContain("Implement the feature.");
     expect(result).toContain("## Report");
     expect(result).toContain("Summarize changes.");
-    expect(result).not.toContain("legacy prompt");
   });
 
-  test("legacy: only systemPrompt", () => {
-    const role: RoleDefinition = {
-      description: "A planner",
-      systemPrompt: "You are a planning agent.",
-      identity: null,
-      prepare: null,
-      execute: null,
-      report: null,
-      outputSchema: "placeholder00000" as string,
-    };
-    const result = buildRolePrompt(role);
-    expect(result).toBe("You are a planning agent.");
-  });
-
-  test("legacy: no fields at all", () => {
-    const role = {
-      description: "Minimal",
-      outputSchema: "placeholder00000",
-    } as unknown as RoleDefinition;
-    const result = buildRolePrompt(role);
-    expect(result).toBe("");
-  });
-
-  test("mixed: identity present, partial other fields", () => {
+  test("empty fields are omitted", () => {
     const role: RoleDefinition = {
       description: "A reviewer",
-      systemPrompt: "legacy",
       identity: "You are a code reviewer.",
-      prepare: null,
+      prepare: "",
       execute: "Review the PR diff carefully.",
-      report: null,
+      report: "",
       outputSchema: "placeholder00000" as string,
     };
     const result = buildRolePrompt(role);
@@ -63,6 +37,18 @@ describe("buildRolePrompt", () => {
     expect(result).toContain("## Execute");
     expect(result).not.toContain("## Prepare");
     expect(result).not.toContain("## Report");
-    expect(result).not.toContain("legacy");
+  });
+
+  test("all empty returns empty string", () => {
+    const role: RoleDefinition = {
+      description: "Minimal",
+      identity: "",
+      prepare: "",
+      execute: "",
+      report: "",
+      outputSchema: "placeholder00000" as string,
+    };
+    const result = buildRolePrompt(role);
+    expect(result).toBe("");
   });
 });

packages/workflow-agent-kit/src/build-role-prompt.ts

@@ -3,37 +3,25 @@ import type { RoleDefinition } from "@uncaged/workflow-protocol";
 /**
  * Build the role prompt from a RoleDefinition.
  *
- * Four-phase mode (identity/prepare/execute/report present):
- *   Assembles structured sections for each phase.
- *
- * Legacy mode (only systemPrompt):
- *   Returns systemPrompt as-is.
- *
- * When both are present, four-phase fields take priority.
+ * Assembles structured sections: Identity, Prepare, Execute, Report.
+ * Empty strings are omitted from the output.
  */
 export function buildRolePrompt(role: RoleDefinition): string {
-  const hasFourPhase =
-    role.identity !== null &&
-    role.identity !== undefined &&
-    role.identity !== "";
-
-  if (!hasFourPhase) {
-    return role.systemPrompt ?? "";
-  }
-
   const sections: string[] = [];
 
-  sections.push(`## Identity\n\n${role.identity}`);
+  if (role.identity !== "") {
+    sections.push(`## Identity\n\n${role.identity}`);
+  }
 
-  if (role.prepare !== null && role.prepare !== undefined && role.prepare !== "") {
+  if (role.prepare !== "") {
     sections.push(`## Prepare\n\n${role.prepare}`);
   }
 
-  if (role.execute !== null && role.execute !== undefined && role.execute !== "") {
+  if (role.execute !== "") {
     sections.push(`## Execute\n\n${role.execute}`);
   }
 
-  if (role.report !== null && role.report !== undefined && role.report !== "") {
+  if (role.report !== "") {
     sections.push(`## Report\n\n${role.report}`);
   }
 

packages/workflow-agent-kit/src/types.ts

@@ -7,7 +7,7 @@ export type AgentContext = ModeratorContext & {
   store: Store;
   workflow: WorkflowPayload;
   /**
-   * Prepend to the role's systemPrompt when building the agent prompt.
+   * Prepend to the role's prompt when building the agent prompt.
    * Contains the frontmatter deliverable format instruction derived from the
    * role's output schema.  Populated by `createAgent` at run time.
    */

packages/workflow-moderator/__tests__/evaluate.test.ts

@@ -9,17 +9,26 @@ const solveIssueWorkflow: WorkflowPayload = {
   roles: {
     planner: {
       description: "Creates implementation plan",
-      systemPrompt: "You are a planning agent...",
+      identity: "You are a planning agent.",
+      prepare: "Review the issue context.",
+      execute: "Create a step-by-step plan.",
+      report: "Output the plan and steps.",
       outputSchema: "5GWKR8TN1V3JA",
     },
     developer: {
       description: "Implements code changes",
-      systemPrompt: "You are a developer agent...",
+      identity: "You are a developer agent.",
+      prepare: "Load coding tools.",
+      execute: "Implement the plan.",
+      report: "List files changed and summary.",
       outputSchema: "8CNWT4KR6D1HV",
     },
     reviewer: {
       description: "Reviews code changes",
-      systemPrompt: "You are a code reviewer...",
+      identity: "You are a code reviewer.",
+      prepare: "Review project conventions.",
+      execute: "Review the implementation.",
+      report: "Approve or reject with comments.",
       outputSchema: "1VPBG9SM5E7WK",
     },
   },

packages/workflow-protocol/src/schemas.ts

@@ -2,10 +2,9 @@ import type { JSONSchema } from "@uncaged/json-cas";
 
 const ROLE_DEFINITION: JSONSchema = {
   type: "object",
-  required: ["description", "outputSchema"],
+  required: ["description", "identity", "prepare", "execute", "report", "outputSchema"],
   properties: {
     description: { type: "string" },
-    systemPrompt: { type: "string" },
     identity: { type: "string" },
     prepare: { type: "string" },
     execute: { type: "string" },

packages/workflow-protocol/src/types.ts

@@ -18,11 +18,10 @@ export type StepRecord = {
 
 export type RoleDefinition = {
   description: string;
-  systemPrompt: string | null;
-  identity: string | null;
-  prepare: string | null;
-  execute: string | null;
-  report: string | null;
+  identity: string;
+  prepare: string;
+  execute: string;
+  report: string;
   outputSchema: CasRef;
 };