diff --git a/src/fable5/context-workspace-receipt.test.ts b/src/fable5/context-workspace-receipt.test.ts
new file mode 100644
index 0000000..aa1744f
--- /dev/null
+++ b/src/fable5/context-workspace-receipt.test.ts
@@ -0,0 +1,57 @@
+import * as fs from "node:fs";
+import * as os from "node:os";
+import * as path from "node:path";
+import { describe, expect, it } from "vitest";
+import { createContextWorkspaceReceipt, writeContextWorkspaceReceipt } from "./context-workspace-receipt.js";
+
+const stage = {
+  name: "Research",
+  folder: "stages/01_research",
+  job: "Collect source material",
+  inputs: [
+    { layer: "layer0_identity" as const, path: "CLAUDE.md" },
+    { layer: "layer1_routing" as const, path: "CONTEXT.md" },
+    { layer: "layer2_stage" as const, path: "stages/01_research/CONTEXT.md" },
+    { layer: "layer3_reference" as const, path: "references/style.md" },
+    { layer: "layer4_working" as const, path: "input/brief.md" },
+  ],
+  outputs: ["stages/01_research/output/research.md"],
+};
+
+describe("context workspace receipt", () => {
+  it("records ICM-style stage contracts as editable filesystem context", () => {
+    const receipt = createContextWorkspaceReceipt({
+      workspace: "workspace",
+      stages: [stage],
+      now: new Date("2026-06-28T00:00:00.000Z"),
+    });
+
+    expect(receipt.schema).toBe("fable.context_workspace.receipt.v1");
+    expect(receipt.source).toContain("2603.16021");
+    expect(receipt.decision).toBe("ready");
+    expect(receipt.principles).toContain("plain text as interface");
+    expect(receipt.stages[0].inputs.map((input) => input.layer)).toContain("layer3_reference");
+  });
+
+  it("blocks vague stages without explicit inputs and outputs", () => {
+    const receipt = createContextWorkspaceReceipt({
+      workspace: "workspace",
+      stages: [{ name: "x", folder: "", job: "", inputs: [], outputs: [] }],
+    });
+
+    expect(receipt.decision).toBe("blocked");
+    expect(receipt.reasons).toContain("each stage needs a folder");
+    expect(receipt.reasons).toContain("each stage needs one job");
+    expect(receipt.reasons).toContain("each stage needs explicit inputs");
+    expect(receipt.reasons).toContain("each stage needs explicit outputs");
+  });
+
+  it("writes a JSON receipt", () => {
+    const dir = fs.mkdtempSync(path.join(os.tmpdir(), "context-workspace-"));
+    const file = path.join(dir, "receipt.json");
+
+    writeContextWorkspaceReceipt(file, createContextWorkspaceReceipt({ workspace: "workspace", stages: [stage] }));
+
+    expect(fs.readFileSync(file, "utf-8")).toContain("fable.context_workspace.receipt.v1");
+  });
+});
diff --git a/src/fable5/context-workspace-receipt.ts b/src/fable5/context-workspace-receipt.ts
new file mode 100644
index 0000000..4b988e5
--- /dev/null
+++ b/src/fable5/context-workspace-receipt.ts
@@ -0,0 +1,57 @@
+import * as fs from "node:fs";
+import * as path from "node:path";
+
+export type ContextLayer = "layer0_identity" | "layer1_routing" | "layer2_stage" | "layer3_reference" | "layer4_working";
+
+export interface ContextStageContract {
+  name: string;
+  folder: string;
+  job: string;
+  inputs: Array<{ layer: ContextLayer; path: string }>;
+  outputs: string[];
+}
+
+export interface ContextWorkspaceReceiptOptions {
+  workspace: string;
+  source?: string;
+  stages: ContextStageContract[];
+  now?: Date;
+}
+
+export interface ContextWorkspaceReceipt {
+  schema: "fable.context_workspace.receipt.v1";
+  createdAt: string;
+  source: string;
+  workspace: string;
+  stages: ContextStageContract[];
+  principles: string[];
+  decision: "ready" | "blocked";
+  reasons: string[];
+}
+
+export function createContextWorkspaceReceipt(opts: ContextWorkspaceReceiptOptions): ContextWorkspaceReceipt {
+  const reasons: string[] = [];
+  if (!opts.workspace.trim()) reasons.push("missing workspace");
+  if (opts.stages.length === 0) reasons.push("missing stages");
+  if (opts.stages.some((stage) => !stage.folder.trim())) reasons.push("each stage needs a folder");
+  if (opts.stages.some((stage) => !stage.job.trim())) reasons.push("each stage needs one job");
+  if (opts.stages.some((stage) => stage.inputs.length === 0)) reasons.push("each stage needs explicit inputs");
+  if (opts.stages.some((stage) => stage.outputs.length === 0)) reasons.push("each stage needs explicit outputs");
+
+  return {
+    schema: "fable.context_workspace.receipt.v1",
+    createdAt: (opts.now ?? new Date()).toISOString(),
+    source: opts.source ?? "ICM paper: https://arxiv.org/abs/2603.16021",
+    workspace: opts.workspace,
+    stages: opts.stages,
+    principles: ["one stage, one job", "plain text as interface", "layered context loading", "outputs are edit surfaces"],
+    decision: reasons.length ? "blocked" : "ready",
+    reasons,
+  };
+}
+
+export function writeContextWorkspaceReceipt(file: string, receipt: ContextWorkspaceReceipt): string {
+  fs.mkdirSync(path.dirname(file), { recursive: true });
+  fs.writeFileSync(file, `${JSON.stringify(receipt, null, 2)}\n`);
+  return file;
+}
diff --git a/src/fable5/index.ts b/src/fable5/index.ts
index 47eb4a4..26d21ad 100644
--- a/src/fable5/index.ts
+++ b/src/fable5/index.ts
@@ -96,6 +96,9 @@ export type { ModelAccessProbe, ModelAccessReceipt, ModelAccessReceiptOptions, M
 export { createPlanReceipt, writePlanReceipt } from "./plan-receipt.js";
 export type { PlanPhase, PlanReceipt, PlanReceiptOptions } from "./plan-receipt.js";
 
+export { createContextWorkspaceReceipt, writeContextWorkspaceReceipt } from "./context-workspace-receipt.js";
+export type { ContextLayer, ContextStageContract, ContextWorkspaceReceipt, ContextWorkspaceReceiptOptions } from "./context-workspace-receipt.js";
+
 export { auditGoalCompletion, writeGoalAuditReceipt } from "./goal-audit.js";
 export type { GoalAuditCriterion, GoalAuditReceipt } from "./goal-audit.js";