feat: replace $START _ status with new/resume semantics

BREAKING: All workflow YAML files must update $START._ to $START.new + $START.resume.
The resume edge prompt replaces the previously hardcoded resume message.

- evaluate.ts: remove START_ROLE/START_STATUS special case, use $status like all nodes
- thread.ts: resolveEvaluateArgs passes 'new', cmdThreadResume passes 'resume'
- validate.ts: reject '_' everywhere (no longer valid)
- validate-semantic.ts: require 'new' and 'resume' edges on $START
- All workflow YAMLs and test fixtures updated

Fixes #101

.changeset/start-new-resume.md

@@ -0,0 +1,9 @@
+---
+"@united-workforce/cli": minor
+"@united-workforce/util": patch
+---
+
+feat: replace $START `_` status with `new`/`resume` semantics
+
+BREAKING: All workflow YAML files must update `$START._` to `$START.new` + `$START.resume`.
+The `resume` edge prompt replaces the previously hardcoded resume message in the CLI.

.workflows/e2e-walkthrough.yaml

@@ -264,7 +264,8 @@ roles:
 
 graph:
   $START:
-    _: { role: "bootstrap", prompt: "Set up the Docker container and verify uwf is runnable." }
+    new: { role: "bootstrap", prompt: "Set up the Docker container and verify uwf is runnable." }
+    resume: { role: "bootstrap", prompt: "Review the previous run output and continue the walkthrough." }
   bootstrap:
     pass: { role: "config-and-registry", prompt: "Container {{{containerName}}} is ready. Validate config and workflow registration." }
     fail: { role: "$END", prompt: "Bootstrap failed: {{{error}}}. No container was created." }

.workflows/solve-issue.yaml

@@ -227,7 +227,8 @@ roles:
           required: [$status, error]
 graph:
   $START:
-    _: { role: "planner", prompt: "Analyze the issue and produce an implementation plan." }
+    new: { role: "planner", prompt: "Analyze the issue and produce an implementation plan." }
+    resume: { role: "planner", prompt: "Review the previous run output and continue the work." }
   planner:
     insufficient_info: { role: "$SUSPEND", prompt: "信息不足，需要补充：{{{reason}}}" }
     ready: { role: "developer", prompt: "Implement the TDD test spec (CAS hash: {{{plan}}}) in repo {{{repoPath}}}. Repo remote: {{{repoRemote}}}." }

examples/analyze-topic.yaml

@@ -35,6 +35,7 @@ roles:
       required: [$status, thesis, keyPoints]
 graph:
   $START:
-    _: { role: "analyst", prompt: "Analyze the topic in the task and produce a structured summary with key points." }
+    new: { role: "analyst", prompt: "Analyze the topic in the task and produce a structured summary with key points." }
+    resume: { role: "analyst", prompt: "Review the previous analysis output and continue with additional context." }
   analyst:
     done: { role: "$END", prompt: "Analysis complete. Finish the workflow." }

examples/debate.yaml

@@ -53,7 +53,8 @@ roles:
       required: [$status, argument]
 graph:
   $START:
-    _: { role: "against", prompt: "Present your opening argument against the proposition." }
+    new: { role: "against", prompt: "Present your opening argument against the proposition." }
+    resume: { role: "against", prompt: "Review the previous debate output and continue the argument against the proposition." }
   against:
     conceded: { role: "$END", prompt: "The against side conceded. Debate over." }
     continue: { role: "for", prompt: "Counter the opposing argument: {{{argument}}}" }

examples/eval-simple.yaml

@@ -25,6 +25,7 @@ roles:
       required: [$status, summary]
 graph:
   $START:
-    _: { role: "fixer", prompt: "Fix the code issue described in the task prompt." }
+    new: { role: "fixer", prompt: "Fix the code issue described in the task prompt." }
+    resume: { role: "fixer", prompt: "Review the previous run output and continue fixing the code issue." }
   fixer:
     done: { role: "$END", prompt: "Fix complete." }

examples/solve-issue.yaml

@@ -215,7 +215,8 @@ roles:
           required: [$status, error]
 graph:
   $START:
-    _: { role: "planner", prompt: "Analyze the issue and produce an implementation plan." }
+    new: { role: "planner", prompt: "Analyze the issue and produce an implementation plan." }
+    resume: { role: "planner", prompt: "Review the previous run output and continue the work." }
   planner:
     insufficient_info: { role: "$SUSPEND", prompt: "信息不足，需要补充：{{{reason}}}" }
     ready: { role: "developer", prompt: "Implement the TDD test spec (CAS hash: {{{plan}}}) in repo {{{repoPath}}}." }

packages/cli/src/__tests__/adapter-json-roundtrip.test.ts

@@ -58,7 +58,10 @@ describe("C1: adapter JSON round-trip integration", () => {
         },
       },
       graph: {
-        $START: { _: { role: "worker", prompt: "Do the work", location: null } },
+        $START: {
+          new: { role: "worker", prompt: "Do the work", location: null },
+          resume: { role: "worker", prompt: "Resume the work", location: null },
+        },
         worker: { done: { role: "$END", prompt: "completed", location: null } },
       },
     });

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

@@ -45,10 +45,14 @@ roles:
         $status: { type: string, enum: ["done"] }
 graph:
   $START:
-    _:
+    new:
       role: roleA
       prompt: "Do A"
       location: null
+    resume:
+      role: roleA
+      prompt: "Resume A"
+      location: null
   roleA:
     ready:
       role: roleB
@@ -107,10 +111,14 @@ roles:
         $status: { type: string, enum: ["done"] }
 graph:
   $START:
-    _:
+    new:
       role: roleA
       prompt: "Do A"
       location: null
+    resume:
+      role: roleA
+      prompt: "Resume A"
+      location: null
   roleA:
     pass:
       role: roleB
@@ -150,10 +158,14 @@ roles:
         $status: { type: string, enum: ["done"] }
 graph:
   $START:
-    _:
+    new:
       role: worker
       prompt: "Work"
       location: null
+    resume:
+      role: worker
+      prompt: "Resume work"
+      location: null
   worker:
     done:
       role: $END

packages/cli/src/__tests__/fixtures/e2e-count.workflow.yaml

@@ -36,7 +36,8 @@ roles:
           required: [$status]
 graph:
   $START:
-    _: { role: analyst, prompt: 'Analyze the task' }
+    new: { role: analyst, prompt: 'Analyze the task' }
+    resume: { role: analyst, prompt: 'Review the previous run output and continue the work.' }
   analyst:
     analyzed: { role: developer, prompt: 'Implement the change' }
   developer:

packages/cli/src/__tests__/fixtures/e2e-linear.workflow.yaml

@@ -25,7 +25,8 @@ roles:
           required: [$status]
 graph:
   $START:
-    _: { role: planner, prompt: 'Plan the task' }
+    new: { role: planner, prompt: 'Plan the task' }
+    resume: { role: planner, prompt: 'Review the previous run output and continue the work.' }
   planner:
     ready: { role: worker, prompt: 'Do the work' }
   worker:

packages/cli/src/__tests__/fixtures/e2e-loop.workflow.yaml

@@ -28,7 +28,8 @@ roles:
           required: [$status]
 graph:
   $START:
-    _: { role: developer, prompt: 'Implement the change' }
+    new: { role: developer, prompt: 'Implement the change' }
+    resume: { role: developer, prompt: 'Review the previous run output and continue the work.' }
   developer:
     review_needed: { role: reviewer, prompt: 'Review the change' }
   reviewer:

packages/cli/src/__tests__/fixtures/e2e-mustache.workflow.yaml

@@ -27,7 +27,8 @@ roles:
           required: [$status]
 graph:
   $START:
-    _: { role: planner, prompt: 'Plan the task' }
+    new: { role: planner, prompt: 'Plan the task' }
+    resume: { role: planner, prompt: 'Review the previous run output and continue the work.' }
   planner:
     ready: { role: worker, prompt: 'Work on branch {{{branch}}} in {{{repoPath}}}' }
   worker:

packages/cli/src/__tests__/fixtures/e2e-suspend.workflow.yaml

@@ -18,7 +18,8 @@ roles:
           required: [$status]
 graph:
   $START:
-    _: { role: planner, prompt: 'Analyze the task' }
+    new: { role: planner, prompt: 'Analyze the task' }
+    resume: { role: planner, prompt: 'Review the previous run output and continue the work.' }
   planner:
     insufficient_info: { role: '$SUSPEND', prompt: 'Need more info: {{{reason}}}' }
     ready: { role: '$END', prompt: 'Done' }

packages/cli/src/__tests__/moderator-evaluate.test.ts

@@ -5,7 +5,12 @@ import { evaluate } from "../moderator/evaluate.js";
 
 const solveIssueGraph: WorkflowPayload["graph"] = {
   $START: {
-    _: { role: "planner", prompt: "Start planning from the issue in the task.", location: null },
+    new: { role: "planner", prompt: "Start planning from the issue in the task.", location: null },
+    resume: {
+      role: "planner",
+      prompt: "Review the previous run output and continue the work.",
+      location: null,
+    },
   },
   planner: {
     planned: { role: "developer", prompt: "Implement the plan: {{plan}}", location: null },
@@ -20,8 +25,8 @@ const solveIssueGraph: WorkflowPayload["graph"] = {
 };
 
 describe("evaluate", () => {
-  test("$START → first role (unit status _)", () => {
+  test("$START → first role (status new)", () => {
-    const result = evaluate(solveIssueGraph, "$START", { $status: "_" });
+    const result = evaluate(solveIssueGraph, "$START", { $status: "new" });
     expect(result).toEqual({
       ok: true,
       value: {
@@ -32,6 +37,18 @@ describe("evaluate", () => {
     });
   });
 
+  test("$START → first role (status resume)", () => {
+    const result = evaluate(solveIssueGraph, "$START", { $status: "resume" });
+    expect(result).toEqual({
+      ok: true,
+      value: {
+        role: "planner",
+        prompt: "Review the previous run output and continue the work.",
+        location: null,
+      },
+    });
+  });
+
   test("status-based routing (reviewer rejected → developer)", () => {
     const result = evaluate(solveIssueGraph, "reviewer", {
       $status: "rejected",
@@ -95,7 +112,7 @@ describe("evaluate", () => {
   });
 
   test("missing role in graph → error", () => {
-    const result = evaluate(solveIssueGraph, "unknown-role", { $status: "_" });
+    const result = evaluate(solveIssueGraph, "unknown-role", { $status: "new" });
     expect(result.ok).toBe(false);
     if (!result.ok) {
       expect(result.error.message).toBe('no transitions defined for role "unknown-role"');

packages/cli/src/__tests__/step-timing.test.ts

@@ -253,7 +253,10 @@ describe("thread read timing", () => {
         },
       },
       graph: {
-        $START: { _: { role: "worker", prompt: "go", location: null } },
+        $START: {
+          new: { role: "worker", prompt: "go", location: null },
+          resume: { role: "worker", prompt: "resume", location: null },
+        },
         worker: { done: { role: "$END", prompt: "", location: null } },
       },
     });
@@ -319,7 +322,10 @@ describe("thread read timing", () => {
         },
       },
       graph: {
-        $START: { _: { role: "worker", prompt: "go", location: null } },
+        $START: {
+          new: { role: "worker", prompt: "go", location: null },
+          resume: { role: "worker", prompt: "resume", location: null },
+        },
         worker: { done: { role: "$END", prompt: "", location: null } },
       },
     });

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

@@ -57,10 +57,14 @@ roles:
         $status: { type: string, enum: ["ready"] }
 graph:
   $START:
-    _:
+    new:
       role: planner
       prompt: "Plan the work"
       location: null
+    resume:
+      role: planner
+      prompt: "Resume the work"
+      location: null
   planner:
     ready:
       role: $END
@@ -113,10 +117,14 @@ roles:
         $status: { type: string, enum: ["ready"] }
 graph:
   $START:
-    _:
+    new:
       role: planner
       prompt: "Plan"
       location: null
+    resume:
+      role: planner
+      prompt: "Resume"
+      location: null
   planner:
     ready:
       role: $END
@@ -156,10 +164,14 @@ roles:
         $status: { type: string, enum: ["ready"] }
 graph:
   $START:
-    _:
+    new:
       role: planner
       prompt: "Plan"
       location: null
+    resume:
+      role: planner
+      prompt: "Resume"
+      location: null
   planner:
     ready:
       role: $END

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

@@ -70,7 +70,10 @@ async function setupSuspendedThread(mode: MockAgentMode): Promise<{
       },
     },
     graph: {
-      $START: { _: { role: "worker", prompt: "Start work", location: null } },
+      $START: {
+        new: { role: "worker", prompt: "Start work", location: null },
+        resume: { role: "worker", prompt: "Resume the work", location: null },
+      },
       worker: {
         needs_input: {
           role: "$SUSPEND",
@@ -233,7 +236,10 @@ describe("uwf thread resume", () => {
         },
       },
       graph: {
-        $START: { _: { role: "worker", prompt: "Start", location: null } },
+        $START: {
+          new: { role: "worker", prompt: "Start", location: null },
+          resume: { role: "worker", prompt: "Resume", location: null },
+        },
         worker: { done: { role: "$END", prompt: "Done", location: null } },
       },
     });
@@ -479,7 +485,10 @@ describe("uwf thread resume - completed threads", () => {
         },
       },
       graph: {
-        $START: { _: { role: "worker", prompt: "Start work", location: null } },
+        $START: {
+          new: { role: "worker", prompt: "Start work", location: null },
+          resume: { role: "worker", prompt: "Resume the work", location: null },
+        },
         worker: { done: { role: "reviewer", prompt: "Review the work", location: null } },
         reviewer: { done: { role: "$END", prompt: "Done", location: null } },
       },
@@ -610,7 +619,7 @@ echo '${adapterJson}'
     expect(cliOutput.done).toBe(false);
 
     const capturedPrompt = await readFile(promptCapturePath, "utf8");
-    expect(capturedPrompt).toContain("Previous run completed");
+    expect(capturedPrompt).toContain("Resume the work");
     expect(capturedPrompt).toContain("Additional context");
 
     const storeModule = await import("../store.js");
@@ -640,7 +649,10 @@ echo '${adapterJson}'
         },
       },
       graph: {
-        $START: { _: { role: "worker", prompt: "Start", location: null } },
+        $START: {
+          new: { role: "worker", prompt: "Start", location: null },
+          resume: { role: "worker", prompt: "Resume", location: null },
+        },
         worker: { done: { role: "$END", prompt: "Done", location: null } },
       },
     });
@@ -688,7 +700,10 @@ echo '${adapterJson}'
         },
       },
       graph: {
-        $START: { _: { role: "worker", prompt: "Start", location: null } },
+        $START: {
+          new: { role: "worker", prompt: "Start", location: null },
+          resume: { role: "worker", prompt: "Resume", location: null },
+        },
         worker: { done: { role: "$END", prompt: "Done", location: null } },
       },
     });

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

@@ -34,10 +34,14 @@ roles:
         $status: { type: string, enum: ["ready"] }
 graph:
   $START:
-    _:
+    new:
       role: planner
       prompt: "Plan the work"
       location: null
+    resume:
+      role: planner
+      prompt: "Resume the work"
+      location: null
   planner:
     ready:
       role: $END
@@ -66,10 +70,14 @@ roles:
             question: { type: string }
 graph:
   $START:
-    _:
+    new:
       role: worker
       prompt: "Start work"
       location: null
+    resume:
+      role: worker
+      prompt: "Resume work"
+      location: null
   worker:
     needs_input:
       role: $SUSPEND

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

@@ -57,10 +57,14 @@ roles:
         $status: { type: string, enum: ["ready"] }
 graph:
   $START:
-    _:
+    new:
       role: planner
       prompt: "Plan the work"
       location: null
+    resume:
+      role: planner
+      prompt: "Resume the work"
+      location: null
   planner:
     ready:
       role: $END

packages/cli/src/__tests__/thread-suspend-step.test.ts

@@ -58,7 +58,10 @@ describe("suspend step CAS chain and threads.yaml metadata", () => {
           },
         },
         graph: {
-          $START: { _: { role: "worker", prompt: "Start work", location: null } },
+          $START: {
+            new: { role: "worker", prompt: "Start work", location: null },
+            resume: { role: "worker", prompt: "Resume work", location: null },
+          },
           worker: {
             needs_input: {
               role: "$SUSPEND",

packages/cli/src/__tests__/thread-suspended-display.test.ts

@@ -55,7 +55,10 @@ describe("suspended thread display", () => {
           },
         },
         graph: {
-          $START: { _: { role: "worker", prompt: "Start work", location: null } },
+          $START: {
+            new: { role: "worker", prompt: "Start work", location: null },
+            resume: { role: "worker", prompt: "Resume work", location: null },
+          },
           worker: {
             needs_input: {
               role: "$SUSPEND",
@@ -162,7 +165,10 @@ describe("suspended thread display", () => {
           },
         },
         graph: {
-          $START: { _: { role: "worker", prompt: "Start work", location: null } },
+          $START: {
+            new: { role: "worker", prompt: "Start work", location: null },
+            resume: { role: "worker", prompt: "Resume work", location: null },
+          },
           worker: {
             needs_input: {
               role: "$SUSPEND",
@@ -248,7 +254,10 @@ describe("suspended thread display", () => {
           },
         },
         graph: {
-          $START: { _: { role: "worker", prompt: "Start work", location: null } },
+          $START: {
+            new: { role: "worker", prompt: "Start work", location: null },
+            resume: { role: "worker", prompt: "Resume work", location: null },
+          },
         },
       });
 

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

@@ -51,7 +51,10 @@ function makeWorkflow(overrides?: Partial<WorkflowPayload>): WorkflowPayload {
       },
     },
     graph: {
-      $START: { _: { role: "writer", prompt: "Begin writing", location: null } },
+      $START: {
+        new: { role: "writer", prompt: "Begin writing", location: null },
+        resume: { role: "writer", prompt: "Review previous output and continue", location: null },
+      },
       writer: { done: { role: "reviewer", prompt: "Review this: {{{plan}}}", location: null } },
       reviewer: {
         approved: { role: "$END", prompt: "Done: {{{summary}}}", location: null },
@@ -135,27 +138,38 @@ describe("Suite 2: Graph Structure", () => {
     expect(errors.some((e) => e.includes("$START must be defined in graph"))).toBe(true);
   });
 
-  test("2.2 $START has multiple status keys", () => {
+  test("2.2 $START missing resume edge", () => {
     const wf = makeWorkflow();
     wf.graph.$START = {
-      _: { role: "writer", prompt: "Begin", location: null },
+      new: { role: "writer", prompt: "Begin", location: null },
-      other: { role: "reviewer", prompt: "Also", location: null },
     };
     const errors = validateWorkflow(wf);
     expect(
-      errors.some((e) => e.includes('$START must have exactly one edge with status "_"')),
+      errors.some((e) => e.includes('$START must have edges with statuses "new" and "resume"')),
     ).toBe(true);
   });
 
-  test("2.3 $START edge uses non-_ status", () => {
+  test("2.3 $START missing new edge", () => {
     const wf = makeWorkflow();
-    wf.graph.$START = { ready: { role: "writer", prompt: "Begin", location: null } };
+    wf.graph.$START = {
+      resume: { role: "writer", prompt: "Resume", location: null },
+    };
     const errors = validateWorkflow(wf);
     expect(
-      errors.some((e) => e.includes('$START must have exactly one edge with status "_"')),
+      errors.some((e) => e.includes('$START must have edges with statuses "new" and "resume"')),
     ).toBe(true);
   });
 
+  test("2.3b $START with new and resume passes", () => {
+    const wf = makeWorkflow();
+    wf.graph.$START = {
+      new: { role: "writer", prompt: "Begin", location: null },
+      resume: { role: "writer", prompt: "Resume", location: null },
+    };
+    const errors = validateWorkflow(wf);
+    expect(errors.some((e) => e.includes("$START must have edges"))).toBe(false);
+  });
+
   test("2.4 $END has outgoing edges", () => {
     const wf = makeWorkflow();
     wf.graph.$END = { _: { role: "writer", prompt: "Loop", location: null } };
@@ -193,15 +207,18 @@ describe("Suite 2: Graph Structure", () => {
 });
 
 describe("Suite 3: Status-Edge Consistency", () => {
-  test("3.1 user role using _ graph key is rejected", () => {
+  test("3.1 user role using _ graph key is treated as an unknown status", () => {
+    // "_" is no longer special-cased — it's just a status key that does not
+    // match the role's $status enum, so it surfaces as extra/missing keys.
     const wf = makeWorkflow();
     wf.graph.writer = { _: { role: "reviewer", prompt: "Review", location: null } };
     const errors = validateWorkflow(wf);
-    expect(
+    expect(errors.some((e) => e.includes('role "writer" graph has extra status keys: _'))).toBe(
-      errors.some((e) =>
+      true,
-        e.includes('role "writer" must use explicit $status keys in graph, not "_"'),
+    );
-      ),
+    expect(errors.some((e) => e.includes('role "writer" graph is missing status keys: done'))).toBe(
-    ).toBe(true);
+      true,
+    );
   });
 
   test("3.2 user role graph key not matching $status enum", () => {
@@ -240,13 +257,16 @@ describe("Suite 3: Status-Edge Consistency", () => {
     ).toBe(true);
   });
 
-  test("3.5 multi-exit role with _ key", () => {
+  test("3.5 multi-exit role with _ key is treated as an unknown status", () => {
     const wf = makeWorkflow();
     wf.graph.reviewer = { _: { role: "$END", prompt: "Done", location: null } };
     const errors = validateWorkflow(wf);
+    expect(errors.some((e) => e.includes('role "reviewer" graph has extra status keys: _'))).toBe(
+      true,
+    );
     expect(
       errors.some((e) =>
-        e.includes('role "reviewer" must use explicit $status keys in graph, not "_"'),
+        e.includes('role "reviewer" graph is missing status keys: approved, rejected'),
       ),
     ).toBe(true);
   });

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

@@ -38,7 +38,10 @@ function makeMinimalPayload(name: string, description: string): WorkflowPayload
       },
     },
     graph: {
-      $START: { _: { role: "worker", prompt: "start working", location: null } },
+      $START: {
+        new: { role: "worker", prompt: "start working", location: null },
+        resume: { role: "worker", prompt: "resume working", location: null },
+      },
       worker: { done: { role: "$END", prompt: "done", location: null } },
     },
   };

packages/cli/src/commands/thread.ts

@@ -911,7 +911,7 @@ function resolveEvaluateArgs(
   chain: ChainState,
 ): { lastRole: string; lastOutput: EvaluateLastOutput } {
   if (chain.headIsStart) {
-    return { lastRole: START_ROLE, lastOutput: { [STATUS_KEY]: "_" } };
+    return { lastRole: START_ROLE, lastOutput: { [STATUS_KEY]: "new" } };
   }
 
   const lastStep = chain.stepsNewestFirst[0];
@@ -1037,7 +1037,6 @@ function archiveThread(uwf: UwfStore, threadId: ThreadId, _workflow: CasRef, _he
   completeThread(uwf.varStore, threadId, "completed");
 }
 
-// biome-ignore lint/complexity/noExcessiveCognitiveComplexity: orchestration function with inherent branching
 export async function cmdThreadResume(
   storageRoot: string,
   threadId: ThreadId,
@@ -1101,7 +1100,7 @@ export async function cmdThreadResume(
 
   // status === "completed"
   const workflow = loadWorkflowPayload(uwf, workflowHash);
-  const startResult = evaluate(workflow.graph, START_ROLE, {});
+  const startResult = evaluate(workflow.graph, START_ROLE, { [STATUS_KEY]: "resume" });
   if (!startResult.ok) {
     fail(`failed to evaluate $START: ${startResult.error.message}`);
   }
@@ -1113,11 +1112,7 @@ export async function cmdThreadResume(
   }
 
   const startRole = startResult.value.role;
-  const completedPromptPrefix = "Previous run completed. Resuming with additional context.";
+  const completedResumePrompt = buildResumePrompt(startResult.value.prompt, supplement);
-  const completedResumePrompt =
-    supplement !== null && supplement !== ""
-      ? `${completedPromptPrefix}\n\n${supplement}`
-      : completedPromptPrefix;
 
   const updatedEntry = { ...entry, status: "idle" as const, completedAt: null };
   setThread(uwf.varStore, threadId, updatedEntry);

packages/cli/src/moderator/__tests__/evaluate.test.ts

@@ -6,11 +6,11 @@ describe("Edge prompt template variable resolution", () => {
   test("returns error when rendered prompt is empty string", () => {
     const graph = {
       $START: {
-        _: { role: "classifier", prompt: "{{{userPrompt}}}", location: null },
+        new: { role: "classifier", prompt: "{{{userPrompt}}}", location: null },
       },
     };
 
-    const result = evaluate(graph, "$START", {});
+    const result = evaluate(graph, "$START", { $status: "new" });
 
     expect(result.ok).toBe(false);
     if (!result.ok) {
@@ -22,11 +22,11 @@ describe("Edge prompt template variable resolution", () => {
   test("returns error when rendered prompt is whitespace-only", () => {
     const graph = {
       $START: {
-        _: { role: "classifier", prompt: "  {{{userPrompt}}}  ", location: null },
+        new: { role: "classifier", prompt: "  {{{userPrompt}}}  ", location: null },
       },
     };
 
-    const result = evaluate(graph, "$START", {});
+    const result = evaluate(graph, "$START", { $status: "new" });
 
     expect(result.ok).toBe(false);
     if (!result.ok) {
@@ -38,11 +38,11 @@ describe("Edge prompt template variable resolution", () => {
   test("succeeds when all template variables resolve to non-empty values", () => {
     const graph = {
       $START: {
-        _: { role: "classifier", prompt: "{{{userPrompt}}}", location: null },
+        new: { role: "classifier", prompt: "{{{userPrompt}}}", location: null },
       },
     };
 
-    const result = evaluate(graph, "$START", { userPrompt: "Fix the bug" });
+    const result = evaluate(graph, "$START", { $status: "new", userPrompt: "Fix the bug" });
 
     expect(result.ok).toBe(true);
     if (result.ok) {
@@ -53,11 +53,11 @@ describe("Edge prompt template variable resolution", () => {
   test("succeeds with static (no-variable) prompt", () => {
     const graph = {
       $START: {
-        _: { role: "classifier", prompt: "Classify this input", location: null },
+        new: { role: "classifier", prompt: "Classify this input", location: null },
       },
     };
 
-    const result = evaluate(graph, "$START", {});
+    const result = evaluate(graph, "$START", { $status: "new" });
 
     expect(result.ok).toBe(true);
     if (result.ok) {
@@ -68,11 +68,11 @@ describe("Edge prompt template variable resolution", () => {
   test("succeeds when prompt has mix of static text and unresolved variables", () => {
     const graph = {
       $START: {
-        _: { role: "classifier", prompt: "Please handle: {{{userPrompt}}}", location: null },
+        new: { role: "classifier", prompt: "Please handle: {{{userPrompt}}}", location: null },
       },
     };
 
-    const result = evaluate(graph, "$START", {});
+    const result = evaluate(graph, "$START", { $status: "new" });
 
     expect(result.ok).toBe(true);
     if (result.ok) {
@@ -83,11 +83,11 @@ describe("Edge prompt template variable resolution", () => {
   test("returns error when ALL variables missing and no static text remains", () => {
     const graph = {
       $START: {
-        _: { role: "classifier", prompt: "{{{a}}}{{{b}}}", location: null },
+        new: { role: "classifier", prompt: "{{{a}}}{{{b}}}", location: null },
       },
     };
 
-    const result = evaluate(graph, "$START", {});
+    const result = evaluate(graph, "$START", { $status: "new" });
 
     expect(result.ok).toBe(false);
   });

packages/cli/src/moderator/evaluate.ts

@@ -6,10 +6,7 @@ import type { EvaluateResult, Result } from "./types.js";
 // Disable HTML escaping — prompts are plain text, not HTML.
 mustache.escape = (text: string) => text;
 
-const START_ROLE = "$START";
 const SUSPEND_ROLE = "$SUSPEND";
-// $START is a special entry node with no agent output — it always uses this key.
-const START_STATUS = "_";
 
 type LastOutput = Record<string, unknown>;
 
@@ -21,9 +18,7 @@ export function evaluate(
   lastOutput: LastOutput,
 ): Result<EvaluateResult, Error> {
   let status: string;
-  if (lastRole === START_ROLE) {
+  if (typeof lastOutput[STATUS_KEY] === "string") {
-    status = START_STATUS;
-  } else if (typeof lastOutput[STATUS_KEY] === "string") {
     status = lastOutput[STATUS_KEY] as string;
   } else {
     return {

packages/cli/src/validate-semantic.ts

@@ -97,9 +97,9 @@ function checkGraphStructure(payload: WorkflowPayload, errors: string[]): void {
   if (!graphNodes.has("$START")) {
     errors.push("$START must be defined in graph");
   } else {
-    const startKeys = Object.keys(payload.graph.$START);
+    const startKeys = new Set(Object.keys(payload.graph.$START));
-    if (startKeys.length !== 1 || startKeys[0] !== "_") {
+    if (!startKeys.has("new") || !startKeys.has("resume")) {
-      errors.push('$START must have exactly one edge with status "_"');
+      errors.push('$START must have edges with statuses "new" and "resume"');
     }
   }
 
@@ -190,22 +190,13 @@ function checkOneOfDiscriminant(
   }
 }
 
-/** Check status-edge consistency for a user role. "_" is reserved for $START and rejected here. */
+/** Check status-edge consistency for a user role. */
 function checkStatusEdges(
   roleName: string,
   graphKeys: Set<string>,
   statusSet: Set<string>,
   errors: string[],
 ): void {
-  if (graphKeys.has("_")) {
-    errors.push(`role "${roleName}" must use explicit $status keys in graph, not "_"`);
-    return;
-  }
-  if (statusSet.has("_")) {
-    errors.push(`role "${roleName}" $status enum must use explicit values, not "_"`);
-    return;
-  }
-
   const extraKeys = [...graphKeys].filter((k) => !statusSet.has(k));
   const missingKeys = [...statusSet].filter((k) => !graphKeys.has(k));
   if (extraKeys.length > 0) {

packages/cli/src/validate.ts

@@ -57,13 +57,13 @@ function isGraph(value: unknown): boolean {
   if (!isRecord(value)) {
     return false;
   }
-  return Object.entries(value).every(([node, statusMap]) => {
+  return Object.values(value).every((statusMap) => {
     if (!isRecord(statusMap)) {
       return false;
     }
     return Object.entries(statusMap).every(([status, target]) => {
-      // "_" is only valid as a status key for the $START entry node.
+      // "_" is no longer a valid status key anywhere — $START uses "new"/"resume".
-      if (status === "_" && node !== "$START") {
+      if (status === "_") {
         return false;
       }
       return isTarget(target);

packages/util/src/moderator-reference.ts

@@ -16,7 +16,8 @@ The graph is a nested map: \`Record<Role | "$START", Record<Status, Target>>\`.
 \`\`\`yaml
 graph:
   $START:
-    _: { role: planner, prompt: "Analyze the issue." }
+    new: { role: planner, prompt: "Analyze the issue." }
+    resume: { role: planner, prompt: "Review the previous run output and continue." }
   planner:
     ready: { role: developer, prompt: "Implement the plan (CAS hash: {{{plan}}})." }
     insufficient_info: { role: $END, prompt: "Not enough info." }
@@ -41,7 +42,7 @@ Edge prompts use triple-brace Mustache syntax (\`{{{field}}}\`) to interpolate v
 
 ## Special Nodes
 
-- \`$START\` — entry point; uses status key \`_\` (unconditional) since there is no previous output
+- \`$START\` — entry point; uses status keys \`new\` (first start) and \`resume\` (resuming a completed thread)
 - \`$END\` — terminal node; thread completes when reached and is moved to history
 
 ## Integration with Steps

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

@@ -40,7 +40,8 @@ roles:                         # named actors
 
 graph:                         # status-based routing
   $START:
-    _: { role: planner, prompt: "Analyze the issue." }
+    new: { role: planner, prompt: "Analyze the issue." }
+    resume: { role: planner, prompt: "Review the previous run output and continue." }
   planner:
     ready: { role: developer, prompt: "Implement {{{plan}}}." }
     failed: { role: $END, prompt: "Failed: {{{error}}}" }
@@ -113,7 +114,7 @@ graph[role][$status] → { role: nextRole, prompt: edgePrompt }
 
 | Node | Purpose |
 |------|---------|
-| \`$START\` | Entry point — status key is always \`_\` (unconditional) |
+| \`$START\` | Entry point — status keys \`new\` (first start) and \`resume\` (resuming a completed thread) |
 | \`$END\` | Terminal — thread completes and is archived |
 
 ### Edge Prompts
@@ -178,7 +179,7 @@ ocas get <output-hash>
 1. Every \`$status\` value in a role's frontmatter has a matching edge in the graph
 2. Every field referenced in edge prompts (\`{{{field}}}\`) exists in the source role's schema
 3. Every role referenced in the graph exists in \`roles\`
-4. \`$START\` has exactly one edge with key \`_\`
+4. \`$START\` has edges with keys \`new\` and \`resume\`
 5. At least one path leads to \`$END\`
 6. No orphan roles (defined but never routed to)
 

packages/util/src/yaml-reference.ts

@@ -32,7 +32,8 @@ roles:                     # named actors in the workflow
 
 graph:                     # status-based routing (nested map)
   $START:
-    _: { role: planner, prompt: "Analyze the issue." }
+    new: { role: planner, prompt: "Analyze the issue." }
+    resume: { role: planner, prompt: "Review the previous run output and continue." }
   planner:
     ready: { role: developer, prompt: "Implement plan {{{plan}}}." }
     insufficient_info: { role: $END, prompt: "Not enough info." }
@@ -70,10 +71,10 @@ Record<Role | "$START", Record<Status, { role: string, prompt: string }>>
 | Level | Key | Value |
 |-------|-----|-------|
 | Outer | Role name or \`$START\` | Status map for that role |
-| Inner | \`$status\` value (or \`_\` for unconditional) | Target: \`{ role, prompt }\` |
+| Inner | \`$status\` value | Target: \`{ role, prompt }\` |
 
 ### Special Nodes
-- \`$START\` — entry point; uses status key \`_\` (unconditional, no previous output)
+- \`$START\` — entry point; uses status keys \`new\` (first start) and \`resume\` (resuming a completed thread)
 - \`$END\` — terminal node; thread completes when reached
 
 ### Edge Prompts

workflows/normalize-bun-monorepo.yaml

@@ -21,9 +21,12 @@ graph:
       role: package-metadata
       prompt: Biome setup failed ({{{reason}}}), but continue. Standardize package metadata for repo at {{{repoPath}}}.
   $START:
-    _:
+    new:
       role: workspace
       prompt: Set up bun workspace structure for repo at {{{repoPath}}}.
+    resume:
+      role: workspace
+      prompt: Review the previous run output and continue setting up the bun workspace structure for repo at {{{repoPath}}}.
   release:
     done:
       role: testing

workflows/solve-issue.yaml

@@ -283,9 +283,12 @@ roles:
         - error
 graph:
   $START:
-    _:
+    new:
       role: planner
       prompt: Analyze the issue and produce an implementation plan.
+    resume:
+      role: planner
+      prompt: Review the previous run output and continue the work.
   planner:
     insufficient_info:
       role: $SUSPEND