diff --git a/packages/loopover-mcp/bin/loopover-mcp.js b/packages/loopover-mcp/bin/loopover-mcp.js
index 51f1154d40..d8db1d2de7 100755
--- a/packages/loopover-mcp/bin/loopover-mcp.js
+++ b/packages/loopover-mcp/bin/loopover-mcp.js
@@ -32,6 +32,8 @@ import { buildTestEvidenceReport } from "@loopover/engine/signals/test-evidence"
 import { evaluateEscalation } from "@loopover/engine";
 // #6752: the same pure composer the remote MCP tool + /v1/loop/results-payload both call.
 import { buildResultsPayload } from "@loopover/engine";
+// #6753: the same pure composer the remote MCP tool + /v1/loop/progress-snapshot both call.
+import { buildProgressSnapshot } from "@loopover/engine";
 // #6755: the same pure bridge the remote MCP tool + /v1/loop/intake-idea both call.
 import { validateIdeaSubmission, buildTaskGraph } from "@loopover/engine";
 import { z } from "zod";
@@ -578,6 +580,19 @@ const resultsPayloadShape = {
   status: z.enum(["open", "merged", "closed"]).optional(),
 };
 
+// #6753: mirrors buildProgressSnapshotShape in src/mcp/server.ts exactly, so the local tool, the remote tool, and
+// the REST route all accept an identical payload.
+const buildProgressSnapshotShape = {
+  iteration: z.number().int(),
+  maxIterations: z.number().int().nullable().optional(),
+  phase: z.enum(["queued", "claiming", "coding", "reviewing", "submitting", "done"]),
+  status: z.enum(["running", "converged", "abandoned", "error"]),
+  recentActivity: z
+    .array(z.object({ step: z.string(), detail: z.string().optional(), at: z.string().optional() }))
+    .max(1000)
+    .optional(),
+};
+
 // #6749: mirrors checkTestEvidenceShape in src/mcp/server.ts VERBATIM (same bounds, same optionality).
 const checkTestEvidenceShape = {
   changedPaths: z.array(z.string().min(1).max(400)).max(2000),
@@ -975,6 +990,12 @@ const STDIO_TOOL_DESCRIPTORS = [
     description:
       "Package a completed loop iteration into the customer-facing result (#4801): a PR link, a plain-language summary, and a bounded diff preview, from already-computed iteration metadata. Deterministic and source-free — it formats the result, it does not fetch, open, or deliver anything. Computed in-process; no API round-trip.",
   },
+  {
+    name: "loopover_build_progress_snapshot",
+    category: "agent",
+    description:
+      "Build a near-real-time progress snapshot for a running rented loop (#4800): phase, status, iteration/percent-complete, and a bounded recent-activity tail, from already-computed loop state. Deterministic and source-free; a customer surface pushes it on change rather than polling on a fixed interval. Computed in-process; no API round-trip.",
+  },
   {
     name: "loopover_intake_idea",
     category: "agent",
@@ -1603,6 +1624,18 @@ registerStdioTool(
   (input) => toolResult("LoopOver loop results payload.", buildResultsPayload(input)),
 );
 
+registerStdioTool(
+  "loopover_build_progress_snapshot",
+  {
+    description: stdioToolDescription("loopover_build_progress_snapshot"),
+    inputSchema: buildProgressSnapshotShape,
+  },
+  // Computed in-process from @loopover/engine (#6753) — the same pure buildProgressSnapshot the remote server
+  // (src/mcp/server.ts) and the /v1/loop/progress-snapshot route both call, so all three surfaces return an
+  // identical snapshot for identical input, and progress composition works fully offline.
+  (input) => toolResult("LoopOver loop progress snapshot.", buildProgressSnapshot(input)),
+);
+
 registerStdioTool(
   "loopover_intake_idea",
   {
diff --git a/src/api/routes.ts b/src/api/routes.ts
index 22f558ff56..b734dd6cb7 100644
--- a/src/api/routes.ts
+++ b/src/api/routes.ts
@@ -203,6 +203,7 @@ import { buildBoundaryTestGenerationFinding, buildBoundaryTestGenerationSpec } f
 import { buildTestEvidenceReport } from "../signals/test-evidence";
 import { evaluateEscalation } from "../loop-escalation";
 import { buildResultsPayload } from "../results-payload";
+import { buildProgressSnapshot } from "../loop-progress";
 import { validateIdeaSubmission, buildTaskGraph } from "../idea-intake";
 import { loadPrAiReviewFindings } from "../mcp/pr-ai-review-findings";
 import {
@@ -525,6 +526,19 @@ const resultsPayloadSchema = z.object({
   status: z.enum(["open", "merged", "closed"]).optional(),
 });
 
+// #6753: mirrors buildProgressSnapshotShape in src/mcp/server.ts VERBATIM (same bounds, same optionality) so the
+// REST surface can never accept an input the MCP tool would reject, or vice versa.
+const progressSnapshotSchema = z.object({
+  iteration: z.number().int(),
+  maxIterations: z.number().int().nullable().optional(),
+  phase: z.enum(["queued", "claiming", "coding", "reviewing", "submitting", "done"]),
+  status: z.enum(["running", "converged", "abandoned", "error"]),
+  recentActivity: z
+    .array(z.object({ step: z.string(), detail: z.string().optional(), at: z.string().optional() }))
+    .max(1000)
+    .optional(),
+});
+
 // #6749: mirrors checkTestEvidenceShape in src/mcp/server.ts VERBATIM (same bounds, same optionality) so the
 // REST surface can never accept an input the MCP tool would reject, or vice versa.
 const testEvidenceSchema = z.object({
@@ -3351,6 +3365,18 @@ export function createApp() {
     return c.json(buildResultsPayload(parsed.data));
   });
 
+  // #6753: REST mirror of the loopover_build_progress_snapshot MCP tool, bringing it to the same REST/CLI parity
+  // its same-tier sibling loopover_check_slop_risk (/v1/lint/slop-risk) already has. Both are pure, source-free
+  // composers over caller-supplied, already-computed loop state, so this route delegates to the same
+  // buildProgressSnapshot the tool calls and adds no logic of its own -- it formats the snapshot, it does not
+  // fetch or stream anything.
+  app.post("/v1/loop/progress-snapshot", async (c) => {
+    const body = await c.req.json().catch(() => null);
+    const parsed = progressSnapshotSchema.safeParse(body);
+    if (!parsed.success) return c.json({ error: "invalid_progress_snapshot_request", issues: parsed.error.issues }, 400);
+    return c.json(buildProgressSnapshot(parsed.data));
+  });
+
   // #6755: REST mirror of the loopover_intake_idea MCP tool, bringing it to the same REST/CLI parity its
   // same-tier sibling loopover_check_slop_risk (/v1/lint/slop-risk) already has. Reproduces the tool's handler
   // exactly -- validate, then assemble the task-graph from the optional caller-supplied decomposition (else the
diff --git a/test/unit/mcp-cli-progress-snapshot-tool.test.ts b/test/unit/mcp-cli-progress-snapshot-tool.test.ts
new file mode 100644
index 0000000000..5055eac3f4
--- /dev/null
+++ b/test/unit/mcp-cli-progress-snapshot-tool.test.ts
@@ -0,0 +1,88 @@
+import { Client } from "@modelcontextprotocol/sdk/client/index.js";
+import { StdioClientTransport } from "@modelcontextprotocol/sdk/client/stdio.js";
+import { mkdtempSync, rmSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import { buildProgressSnapshot, type LoopProgressState } from "../../src/loop-progress";
+
+// #6753: the local mirror of loopover_build_progress_snapshot. Like its same-tier sibling
+// loopover_check_slop_risk, it computes IN-PROCESS from @loopover/engine — no API round-trip — so
+// progress composition works fully offline. The point of these tests is cross-surface PARITY: the
+// stdio tool must return exactly what the pure buildProgressSnapshot returns for identical input
+// (the same function /v1/loop/progress-snapshot delegates to).
+const bin = join(process.cwd(), "packages/loopover-mcp/bin/loopover-mcp.js");
+
+let client: Client;
+let transport: StdioClientTransport;
+let configDir: string;
+
+beforeEach(async () => {
+  configDir = mkdtempSync(join(tmpdir(), "loopover-progress-snapshot-"));
+  transport = new StdioClientTransport({
+    command: "node",
+    args: [bin, "--stdio"],
+    // Pure + in-process: a black-holed API URL proves no round-trip happens.
+    env: {
+      ...process.env,
+      LOOPOVER_CONFIG_DIR: configDir,
+      LOOPOVER_TOKEN: "session-token",
+      LOOPOVER_API_URL: "http://127.0.0.1:1",
+      LOOPOVER_API_TIMEOUT_MS: "1000",
+    },
+  });
+  client = new Client({ name: "progress-snapshot-test", version: "0.0.1" });
+  await client.connect(transport);
+});
+
+afterEach(async () => {
+  await client?.close().catch(() => undefined);
+  if (configDir) rmSync(configDir, { recursive: true, force: true });
+});
+
+describe("loopover_build_progress_snapshot stdio mirror (#6753)", () => {
+  it("registers the tool alongside its same-tier check_slop_risk sibling", async () => {
+    const names = new Set((await client.listTools()).tools.map((t) => t.name));
+    expect(names).toContain("loopover_build_progress_snapshot");
+    expect(names).toContain("loopover_check_slop_risk");
+  });
+
+  it("matches the pure builder for representative states — offline, with no API reachable", async () => {
+    const cases: LoopProgressState[] = [
+      { iteration: 0, phase: "queued", status: "running" },
+      { iteration: 2, maxIterations: 5, phase: "coding", status: "running" },
+      { iteration: 5, maxIterations: 5, phase: "done", status: "converged" },
+      { iteration: 1, maxIterations: null, phase: "reviewing", status: "error" },
+      {
+        iteration: 3,
+        maxIterations: 10,
+        phase: "submitting",
+        status: "abandoned",
+        recentActivity: [{ step: "plan" }, { step: "code", detail: "wrote tests", at: "2026-07-17T00:00:00.000Z" }],
+      },
+    ];
+    for (const args of cases) {
+      const result = await client.callTool({ name: "loopover_build_progress_snapshot", arguments: args });
+      expect(result.isError, JSON.stringify(args)).toBeFalsy();
+      // PARITY: identical to what the REST route returns, because both call this same function.
+      expect((result as { structuredContent?: unknown }).structuredContent, JSON.stringify(args)).toEqual(
+        JSON.parse(JSON.stringify(buildProgressSnapshot(args))),
+      );
+    }
+  });
+
+  it("rejects invalid input (zod input-schema validation)", async () => {
+    for (const args of [
+      {},
+      { iteration: 1, phase: "coding" },
+      { iteration: 1, phase: "bogus", status: "running" },
+      { iteration: 1.5, phase: "coding", status: "running" },
+    ]) {
+      const rejected = await client.callTool({ name: "loopover_build_progress_snapshot", arguments: args }).then(
+        (r) => Boolean(r.isError),
+        () => true,
+      );
+      expect(rejected, `${JSON.stringify(args)} should be rejected`).toBe(true);
+    }
+  });
+});
diff --git a/test/unit/mcp-tool-rename-aliases.test.ts b/test/unit/mcp-tool-rename-aliases.test.ts
index 3f7a6fa988..cb74d301b5 100644
--- a/test/unit/mcp-tool-rename-aliases.test.ts
+++ b/test/unit/mcp-tool-rename-aliases.test.ts
@@ -13,6 +13,7 @@
 // (#6752 registered the loopover_build_results_payload CLI mirror, taking the count from 67 to 68.)
 // (#6755 registered the loopover_intake_idea CLI mirror, taking the count from 68 to 69.)
 // (#6915 registered the loopover_simulate_open_pr_pressure CLI mirror, taking the count from 69 to 70.)
+// (#6753 registered the loopover_build_progress_snapshot CLI mirror, taking the count from 70 to 71.)
 import { Client } from "@modelcontextprotocol/sdk/client/index.js";
 import { StdioClientTransport } from "@modelcontextprotocol/sdk/client/stdio.js";
 import { mkdtempSync, rmSync } from "node:fs";
@@ -56,14 +57,14 @@ describe("MCP legacy alias retirement (#4777) — discovery invariants", () => {
   });
   afterEach(disconnect);
 
-  it("lists exactly 70 loopover_ tools and zero gittensory_-prefixed aliases", async () => {
+  it("lists exactly 71 loopover_ tools and zero gittensory_-prefixed aliases", async () => {
     const { tools } = await client.listTools();
     const names = tools.map((t) => t.name);
     const primary = names.filter((n) => n.startsWith("loopover_"));
     const legacy = names.filter((n) => n.startsWith("gittensory_"));
-    expect(primary.length).toBe(70);
+    expect(primary.length).toBe(71);
     expect(legacy.length).toBe(0);
-    expect(names.length).toBe(70);
+    expect(names.length).toBe(71);
   });
 
   it("no loopover_ tool's description carries a stale deprecation notice", async () => {
@@ -73,11 +74,11 @@ describe("MCP legacy alias retirement (#4777) — discovery invariants", () => {
     }
   });
 
-  it("`loopover-mcp tools --json` reports the same 70-tool count the live server registers", async () => {
+  it("`loopover-mcp tools --json` reports the same 71-tool count the live server registers", async () => {
     const { tools } = await client.listTools();
     const payload = JSON.parse(run(["tools", "--json"])) as { count: number; tools: Array<{ name: string }> };
     expect(payload.count).toBe(tools.length);
-    expect(payload.count).toBe(70);
+    expect(payload.count).toBe(71);
     expect([...payload.tools.map((t) => t.name)].sort()).toEqual([...tools.map((t) => t.name)].sort());
   });
 });
diff --git a/test/unit/routes-progress-snapshot.test.ts b/test/unit/routes-progress-snapshot.test.ts
new file mode 100644
index 0000000000..af8aa78960
--- /dev/null
+++ b/test/unit/routes-progress-snapshot.test.ts
@@ -0,0 +1,94 @@
+import { describe, expect, it } from "vitest";
+import { createApp } from "../../src/api/routes";
+import { buildProgressSnapshot, type LoopProgressState } from "../../src/loop-progress";
+import { createTestEnv } from "../helpers/d1";
+
+// #6753: POST /v1/loop/progress-snapshot — the REST mirror bringing loopover_build_progress_snapshot to the
+// same parity its same-tier sibling loopover_check_slop_risk (/v1/lint/slop-risk) already has. The route
+// delegates to the pure buildProgressSnapshot (covered by its own unit tests), so these pin the ROUTE
+// contract: the snapshot is returned unmodified, and a bad body is rejected.
+const apiHeaders = (env: Env) => ({ authorization: `Bearer ${env.LOOPOVER_API_TOKEN}`, "content-type": "application/json" });
+const PATH = "/v1/loop/progress-snapshot";
+
+const post = (env: Env, body: unknown) =>
+  createApp().request(PATH, { method: "POST", headers: apiHeaders(env), body: JSON.stringify(body) }, env);
+
+describe("POST /v1/loop/progress-snapshot (#6753)", () => {
+  it("returns a progress snapshot for a healthy mid-run loop", async () => {
+    const env = createTestEnv();
+    const body = {
+      iteration: 2,
+      maxIterations: 5,
+      phase: "coding",
+      status: "running",
+      recentActivity: [{ step: "edit", detail: "touched routes.ts" }],
+    } satisfies LoopProgressState;
+    const response = await post(env, body);
+    expect(response.status).toBe(200);
+    await expect(response.json()).resolves.toMatchObject({
+      phase: "coding",
+      status: "running",
+      iteration: 2,
+      maxIterations: 5,
+      percentComplete: 40,
+      done: false,
+    });
+  });
+
+  it("matches the pure builder for every representative state — parity with the MCP tool", async () => {
+    const env = createTestEnv();
+    const cases: LoopProgressState[] = [
+      { iteration: 0, phase: "queued", status: "running" },
+      { iteration: 1, maxIterations: 4, phase: "claiming", status: "running" },
+      { iteration: 3, maxIterations: 3, phase: "done", status: "converged" },
+      { iteration: 1, maxIterations: null, phase: "reviewing", status: "error" },
+      {
+        iteration: 2,
+        maxIterations: 10,
+        phase: "submitting",
+        status: "abandoned",
+        recentActivity: [
+          { step: "plan", at: "2026-07-17T00:00:00.000Z" },
+          { step: "code", detail: "wrote tests" },
+        ],
+      },
+    ];
+    for (const body of cases) {
+      const response = await post(env, body);
+      expect(response.status, JSON.stringify(body)).toBe(200);
+      // PARITY: the route must return exactly what the pure builder the MCP tool calls returns.
+      await expect(response.json()).resolves.toEqual(JSON.parse(JSON.stringify(buildProgressSnapshot(body))));
+    }
+  });
+
+  it("rejects an invalid or unparseable body with 400", async () => {
+    const env = createTestEnv();
+    for (const body of [
+      {},
+      { iteration: 1, phase: "coding" },
+      { iteration: 1, phase: "bogus", status: "running" },
+      { iteration: 1.5, phase: "coding", status: "running" },
+      { iteration: 1, phase: "coding", status: "running", recentActivity: "nope" },
+    ]) {
+      const response = await post(env, body);
+      expect(response.status, JSON.stringify(body)).toBe(400);
+      await expect(response.json()).resolves.toMatchObject({ error: "invalid_progress_snapshot_request" });
+    }
+    const malformed = await createApp().request(
+      PATH,
+      { method: "POST", headers: apiHeaders(createTestEnv()), body: "{not json" },
+      createTestEnv(),
+    );
+    expect(malformed.status).toBe(400);
+  });
+
+  it("leaks no wallet/hotkey/trust-score terms", async () => {
+    const env = createTestEnv();
+    const text = JSON.stringify(
+      await (
+        await post(env, { iteration: 1, maxIterations: 2, phase: "coding", status: "running" })
+      ).json(),
+    );
+    expect(text).not.toMatch(/wallet|hotkey|coldkey|trust score|reward/i);
+  });
+});