diff --git a/src/mcp/server.ts b/src/mcp/server.ts
index b57b117e83..bddf7263de 100644
--- a/src/mcp/server.ts
+++ b/src/mcp/server.ts
@@ -68,6 +68,7 @@ import { loadOrComputeIssueQualityResponse } from "../services/issue-quality";
 import { loadOrComputeBurdenForecastResponse } from "../services/burden-forecast";
 import { buildMcpClientTelemetry } from "../services/client-telemetry";
 import { loadOrComputeRepoOutcomePatternsResponse } from "../services/repo-outcome-patterns";
+import { buildRepoOutcomeCalibration, outcomeCalibrationSummary } from "../services/outcome-calibration";
 import { buildUnavailableQueueTrendReport } from "../services/queue-trends";
 import {
   applyMcpPlanningChoices,
@@ -137,6 +138,12 @@ const ownerRepoShape = {
   repo: z.string().min(1),
 };
 
+const ownerRepoWindowShape = {
+  owner: z.string().min(1),
+  repo: z.string().min(1),
+  windowDays: z.number().int().positive().optional(),
+};
+
 const loginShape = {
   login: z.string().min(1),
 };
@@ -587,6 +594,16 @@ const freshnessResponseOutputSchema = {
   report: z.unknown().optional(),
 };
 
+const maintainerMeasurementReportOutputSchema = {
+  repoFullName: z.string().optional(),
+  generatedAt: z.string().optional(),
+  windowDays: z.number().nullable().optional(),
+  slop: z.unknown().optional(),
+  recommendations: z.unknown().optional(),
+  signals: z.array(z.string()).optional(),
+  status: z.string().optional(),
+};
+
 const contributorProfileOutputSchema = {
   login: z.string().optional(),
   github: z.unknown().optional(),
@@ -1026,6 +1043,17 @@ export class GittensoryMcp {
       async (input) => this.toolResult(await this.getRepoOutcomePatterns(input)),
     );
 
+    server.registerTool(
+      "gittensory_get_outcome_calibration",
+      {
+        description:
+          "Return slop-band and recommendation outcome calibration for a repo: whether higher-slop bands merge less often and how agent recommendations are panning out. Maintainer-authenticated; measurement only.",
+        inputSchema: ownerRepoWindowShape,
+        outputSchema: maintainerMeasurementReportOutputSchema,
+      },
+      async (input) => this.toolResult(await this.getOutcomeCalibration(input)),
+    );
+
     server.registerTool(
       "gittensory_get_contributor_profile",
       {
@@ -1884,6 +1912,16 @@ export class GittensoryMcp {
     };
   }
 
+  private async getOutcomeCalibration(input: { owner: string; repo: string; windowDays?: number | undefined }): Promise<ToolPayload> {
+    const fullName = `${input.owner}/${input.repo}`;
+    await this.requireRepoAccess(fullName);
+    const report = await buildRepoOutcomeCalibration(this.env, fullName, input.windowDays);
+    return {
+      summary: outcomeCalibrationSummary(fullName, report.slop),
+      data: report as unknown as Record<string, unknown>,
+    };
+  }
+
   private async loadOpenQueueCounts(fullName: string): Promise<{ openIssues: number; openPullRequests: number }> {
     const [totals, openIssues, openPullRequests] = await Promise.all([
       getLatestRepoGithubTotalsSnapshot(this.env, fullName),
diff --git a/src/services/outcome-calibration.ts b/src/services/outcome-calibration.ts
index 7681c0f803..1f13ea0a42 100644
--- a/src/services/outcome-calibration.ts
+++ b/src/services/outcome-calibration.ts
@@ -130,6 +130,13 @@ function sameRepo(a: string | null | undefined, b: string): boolean {
   return (a ?? "").toLowerCase() === b.toLowerCase();
 }
 
+/** One-line human summary of a repo's slop-band calibration verdict (mirrors the discriminates signal). Pure. */
+export function outcomeCalibrationSummary(fullName: string, slop: SlopOutcomeCalibration): string {
+  if (slop.discriminates === true) return `Outcome calibration for ${fullName}: slop bands are predictive across ${slop.totalResolved} resolved PRs.`;
+  if (slop.discriminates === false) return `Outcome calibration for ${fullName}: slop bands are NOT discriminating on current data (${slop.totalResolved} resolved PRs).`;
+  return `Outcome calibration for ${fullName}: not enough resolved PR data to judge slop calibration yet.`;
+}
+
 /** Load a repo's PRs + recommendation outcomes and assemble the calibration report. */
 export async function buildRepoOutcomeCalibration(env: Env, repoFullName: string, windowDays?: number): Promise<OutcomeCalibration> {
   const [pullRequests, outcomes] = await Promise.all([
diff --git a/test/integration/api.test.ts b/test/integration/api.test.ts
index 7f2bf062a6..f91cad1263 100644
--- a/test/integration/api.test.ts
+++ b/test/integration/api.test.ts
@@ -4872,6 +4872,7 @@ describe("api routes", () => {
     expect(toolNames).toContain("gittensory_preflight_local_diff");
     expect(toolNames).toContain("gittensory_preview_local_pr_score");
     expect(toolNames).toContain("gittensory_explain_score_breakdown");
+    expect(toolNames).toContain("gittensory_get_outcome_calibration");
     expect(toolNames).toContain("gittensory_get_registry_changes");
     expect(toolNames).toContain("gittensory_get_upstream_drift");
     expect(toolNames).toContain("gittensory_explain_review_risk");
diff --git a/test/unit/mcp-output-schemas.test.ts b/test/unit/mcp-output-schemas.test.ts
index 9c505bbd84..02eb3c9626 100644
--- a/test/unit/mcp-output-schemas.test.ts
+++ b/test/unit/mcp-output-schemas.test.ts
@@ -1,7 +1,7 @@
 import { Client } from "@modelcontextprotocol/sdk/client/index.js";
 import { InMemoryTransport } from "@modelcontextprotocol/sdk/inMemory.js";
 import { describe, expect, it } from "vitest";
-import { persistSignalSnapshot, upsertBounty, upsertIssueFromGitHub, upsertRepositoryFromGitHub } from "../../src/db/repositories";
+import { persistSignalSnapshot, upsertBounty, upsertIssueFromGitHub, upsertPullRequestFromGitHub, upsertRepositoryFromGitHub, updatePullRequestSlopAssessment } from "../../src/db/repositories";
 import { GittensoryMcp } from "../../src/mcp/server";
 import { normalizeRegistryPayload } from "../../src/registry/normalize";
 import { persistRegistrySnapshot } from "../../src/registry/sync";
@@ -13,6 +13,7 @@ const TOOLS_WITH_OUTPUT_SCHEMA = [
   "gittensory_get_repo_context",
   "gittensory_get_burden_forecast",
   "gittensory_get_repo_outcome_patterns",
+  "gittensory_get_outcome_calibration",
   "gittensory_get_contributor_profile",
   "gittensory_get_decision_pack",
   "gittensory_monitor_open_prs",
@@ -380,6 +381,31 @@ describe("MCP tool calls return schema-valid structured content", () => {
     expect(cached.isError).toBeFalsy();
     expect(cached.structuredContent).toMatchObject({ status: "ready", source: "snapshot", freshness: "fresh", repoFullName: "owner/cached" });
   });
+
+  it("gittensory_get_outcome_calibration returns structured slop calibration for a repo", async () => {
+    const env = createTestEnv();
+    await upsertRepositoryFromGitHub(env, { name: "demo", full_name: "octo/demo", private: false, owner: { login: "octo" }, default_branch: "main" });
+    await upsertPullRequestFromGitHub(env, "octo/demo", {
+      number: 1,
+      title: "merged clean",
+      state: "closed",
+      user: { login: "alice" },
+      merged_at: "2026-06-01T00:00:00.000Z",
+    });
+    await updatePullRequestSlopAssessment(env, "octo/demo", 1, { slopRisk: 0, slopBand: "clean" });
+    const { client } = await connectTestClient(env);
+    const result = await client.callTool({
+      name: "gittensory_get_outcome_calibration",
+      arguments: { owner: "octo", repo: "demo", windowDays: 30 },
+    });
+    expect(result.isError).toBeFalsy();
+    const data = result.structuredContent as Record<string, unknown>;
+    expect(data.repoFullName).toBe("octo/demo");
+    expect(data.windowDays).toBe(30);
+    expect(data.slop).toBeTruthy();
+    expect(data.recommendations).toBeTruthy();
+    expect(Array.isArray(data.signals)).toBe(true);
+  });
 });
 
 // ── Public/private safety ─────────────────────────────────────────────────────
diff --git a/test/unit/outcome-calibration.test.ts b/test/unit/outcome-calibration.test.ts
index c901439a43..bebcb41d72 100644
--- a/test/unit/outcome-calibration.test.ts
+++ b/test/unit/outcome-calibration.test.ts
@@ -4,6 +4,8 @@ import {
   buildRecommendationOutcomeCalibration,
   buildRepoOutcomeCalibration,
   buildSlopOutcomeCalibration,
+  outcomeCalibrationSummary,
+  type SlopOutcomeCalibration,
 } from "../../src/services/outcome-calibration";
 import { createAgentRun, replaceAgentActions, updatePullRequestSlopAssessment, upsertAgentRecommendationOutcome, upsertPullRequestFromGitHub } from "../../src/db/repositories";
 import type { SlopBand } from "../../src/signals/slop";
@@ -216,3 +218,30 @@ function actionRecord(id: string, runId: string): AgentActionRecord {
     createdAt: "2026-06-01T00:00:00.000Z",
   };
 }
+
+describe("outcomeCalibrationSummary", () => {
+  const slop = (discriminates: boolean | null, totalResolved: number): SlopOutcomeCalibration => ({
+    totalResolved,
+    bands: [],
+    overallMergeRate: null,
+    discriminates,
+  });
+
+  it("reports a predictive verdict when bands discriminate", () => {
+    expect(outcomeCalibrationSummary("octo/demo", slop(true, 12))).toBe(
+      "Outcome calibration for octo/demo: slop bands are predictive across 12 resolved PRs.",
+    );
+  });
+
+  it("reports a non-discriminating verdict when bands invert", () => {
+    expect(outcomeCalibrationSummary("octo/demo", slop(false, 11))).toBe(
+      "Outcome calibration for octo/demo: slop bands are NOT discriminating on current data (11 resolved PRs).",
+    );
+  });
+
+  it("reports an insufficient-data verdict when discrimination cannot be judged", () => {
+    expect(outcomeCalibrationSummary("octo/demo", slop(null, 2))).toBe(
+      "Outcome calibration for octo/demo: not enough resolved PR data to judge slop calibration yet.",
+    );
+  });
+});