diff --git a/packages/loopover-miner/lib/idea-feasibility.d.ts b/packages/loopover-miner/lib/idea-feasibility.d.ts
new file mode 100644
index 0000000000..9f468155d0
--- /dev/null
+++ b/packages/loopover-miner/lib/idea-feasibility.d.ts
@@ -0,0 +1,51 @@
+import type {
+  FeasibilityClaimStatus,
+  FeasibilityDuplicateClusterRisk,
+  FeasibilityGateInput,
+  FeasibilityGateResult,
+  FeasibilityIssueStatus,
+  FeasibilityVerdict,
+} from "@loopover/engine";
+
+/** A schema-validated idea submission (#4779). This structural gate only reads `acceptanceHints`, but accepts
+ *  the full submission so callers can pass the idea through unchanged. */
+export type IdeaFeasibilityInput = {
+  title?: string | undefined;
+  body?: string | undefined;
+  targetRepo?: string | undefined;
+  constraints?: readonly string[] | undefined;
+  acceptanceHints?: readonly string[] | undefined;
+  priority?: "normal" | "high" | undefined;
+};
+
+/** Objectively-resolved intake signals for the idea (resolved by the caller, never guessed from prose). */
+export type ResolvedIdeaSignals = {
+  targetResolvable: boolean;
+  claimStatus: FeasibilityClaimStatus;
+  duplicateClusterRisk: FeasibilityDuplicateClusterRisk;
+};
+
+export type AssessIdeaFeasibilityOptions = {
+  buildFeasibilityVerdict?: (input: FeasibilityGateInput) => FeasibilityGateResult;
+};
+
+export type IdeaFeasibilityDisposition = "proceed" | "flag" | "reject";
+
+export type IdeaFeasibilityResult = {
+  disposition: IdeaFeasibilityDisposition;
+  verdict: FeasibilityVerdict;
+  issueStatus: FeasibilityIssueStatus;
+  reasons: string[];
+  summary: string;
+};
+
+export function deriveIdeaIssueStatus(
+  idea: IdeaFeasibilityInput,
+  resolved: Pick<ResolvedIdeaSignals, "targetResolvable">,
+): FeasibilityIssueStatus;
+
+export function assessIdeaFeasibility(
+  idea: IdeaFeasibilityInput,
+  resolved: ResolvedIdeaSignals,
+  options?: AssessIdeaFeasibilityOptions,
+): IdeaFeasibilityResult;
diff --git a/packages/loopover-miner/lib/idea-feasibility.js b/packages/loopover-miner/lib/idea-feasibility.js
new file mode 100644
index 0000000000..0c6d24263f
--- /dev/null
+++ b/packages/loopover-miner/lib/idea-feasibility.js
@@ -0,0 +1,68 @@
+/** Pre-execution feasibility check for a freeform Rent-a-Loop idea (#5671).
+ *
+ * Runs post-schema-validation and pre-compute-allocation on an idea submission (the intake shape defined in
+ * #4779), so a customer can no longer burn paid or free-trial compute on an idea that was never going to
+ * succeed. It is the freeform-text counterpart to the metadata `feasibility` CLI (`feasibility-cli.js`, #4270).
+ *
+ * REUSED from feasibility-cli.js AS-IS:
+ *   - the engine's pure `buildFeasibilityVerdict` composer and its `avoid > raise > go` precedence — an idea
+ *     inherits exactly the same verdict machinery a metadata-resolved issue does, so there is no second,
+ *     divergent decision surface;
+ *   - the injectable-verdict test seam (`options.buildFeasibilityVerdict`), matching the CLI's convention.
+ *
+ * NEW for freeform text (#5671, per the #4779 rubric):
+ *   - `deriveIdeaIssueStatus`, which computes the `issueStatus` discriminant from the idea's OWN structure
+ *     instead of a resolved GitHub issue. An idea with no objective success signal is `invalid` (impossible to
+ *     evaluate objectively) and is rejected before compute; an unresolvable target repo is `missing` (out of the
+ *     loop's scope) and is flagged.
+ *
+ * OUT OF SCOPE (stays with #5136): judging abusive/illegal or semantically off-topic intent from prose — that is
+ * a content-moderation policy call, not this deterministic structural gate.
+ */
+import { buildFeasibilityVerdict } from "@loopover/engine";
+
+/** Verdict → caller-facing disposition. `go` proceeds to compute; `raise`/`avoid` gate it. */
+const DISPOSITION_BY_VERDICT = { go: "proceed", raise: "flag", avoid: "reject" };
+
+/**
+ * Derive the feasibility `issueStatus` for a freeform idea from objective, structural signals only — never from
+ * a semantic read of the prose.
+ *
+ * @param {{ acceptanceHints?: readonly string[] }} idea    schema-validated idea submission (#4779)
+ * @param {{ targetResolvable: boolean }} resolved          objectively-resolved intake signals
+ * @returns {"missing" | "invalid" | "ready"}
+ */
+export function deriveIdeaIssueStatus(idea, resolved) {
+  // Out of the loop's scope: the idea does not resolve to a repo the loop can act on.
+  if (!resolved.targetResolvable) return "missing";
+  // Impossible to evaluate objectively: no declared success signal, so the loop could never test its own output.
+  const objectiveSignals = idea.acceptanceHints?.length ?? 0;
+  if (objectiveSignals === 0) return "invalid";
+  return "ready";
+}
+
+/**
+ * Assess a schema-validated idea's feasibility before compute is allocated.
+ *
+ * @param {{ acceptanceHints?: readonly string[] }} idea
+ * @param {{ targetResolvable: boolean, claimStatus: string, duplicateClusterRisk: string }} resolved
+ * @param {{ buildFeasibilityVerdict?: Function }} [options]  test seam; defaults to the engine composer
+ * @returns {{ disposition: "proceed"|"flag"|"reject", verdict: string, issueStatus: string, reasons: string[], summary: string }}
+ */
+export function assessIdeaFeasibility(idea, resolved, options = {}) {
+  const buildVerdict = options.buildFeasibilityVerdict ?? buildFeasibilityVerdict;
+  const issueStatus = deriveIdeaIssueStatus(idea, resolved);
+  const verdict = buildVerdict({
+    found: resolved.targetResolvable,
+    claimStatus: resolved.claimStatus,
+    duplicateClusterRisk: resolved.duplicateClusterRisk,
+    issueStatus,
+  });
+  return {
+    disposition: DISPOSITION_BY_VERDICT[verdict.verdict],
+    verdict: verdict.verdict,
+    issueStatus,
+    reasons: [...verdict.avoidReasons, ...verdict.raiseReasons],
+    summary: verdict.summary,
+  };
+}
diff --git a/test/unit/miner-idea-feasibility.test.ts b/test/unit/miner-idea-feasibility.test.ts
new file mode 100644
index 0000000000..3eaaa352ea
--- /dev/null
+++ b/test/unit/miner-idea-feasibility.test.ts
@@ -0,0 +1,99 @@
+import { describe, expect, it, vi } from "vitest";
+
+vi.mock("@loopover/engine", async () => {
+  return import("../../packages/loopover-engine/src/index");
+});
+
+import {
+  assessIdeaFeasibility,
+  deriveIdeaIssueStatus,
+} from "../../packages/loopover-miner/lib/idea-feasibility.js";
+import type { ResolvedIdeaSignals } from "../../packages/loopover-miner/lib/idea-feasibility.js";
+import type { FeasibilityGateResult } from "@loopover/engine";
+
+function cleanSignals(overrides: Partial<ResolvedIdeaSignals> = {}): ResolvedIdeaSignals {
+  return { targetResolvable: true, claimStatus: "unclaimed", duplicateClusterRisk: "none", ...overrides };
+}
+
+describe("deriveIdeaIssueStatus (#5671)", () => {
+  it("returns 'missing' when the idea's target repo does not resolve (out of the loop's scope)", () => {
+    expect(deriveIdeaIssueStatus({ acceptanceHints: ["retries on 5xx"] }, { targetResolvable: false })).toBe("missing");
+  });
+
+  it("returns 'invalid' when the idea declares NO objective success signal (acceptanceHints absent)", () => {
+    expect(deriveIdeaIssueStatus({}, { targetResolvable: true })).toBe("invalid");
+  });
+
+  it("returns 'invalid' when acceptanceHints is present but empty (still nothing testable)", () => {
+    expect(deriveIdeaIssueStatus({ acceptanceHints: [] }, { targetResolvable: true })).toBe("invalid");
+  });
+
+  it("returns 'ready' when the idea resolves and carries at least one objective success signal", () => {
+    expect(deriveIdeaIssueStatus({ acceptanceHints: ["uploads retry on 5xx"] }, { targetResolvable: true })).toBe("ready");
+  });
+});
+
+describe("assessIdeaFeasibility (#5671)", () => {
+  it("a feasible idea (resolvable target, objective signal, clean metadata) proceeds to compute", () => {
+    const result = assessIdeaFeasibility({ acceptanceHints: ["uploads retry on 5xx"] }, cleanSignals());
+    expect(result.disposition).toBe("proceed");
+    expect(result.verdict).toBe("go");
+    expect(result.issueStatus).toBe("ready");
+    expect(result.reasons).toEqual([]);
+  });
+
+  it("a well-formed but impossible-to-evaluate idea (no objective signal) is REJECTED before compute", () => {
+    const result = assessIdeaFeasibility({ title: "make it better", acceptanceHints: [] }, cleanSignals());
+    expect(result.disposition).toBe("reject");
+    expect(result.verdict).toBe("avoid");
+    expect(result.issueStatus).toBe("invalid");
+    expect(result.reasons).toContain("issue_lifecycle_invalid");
+  });
+
+  it("an ambiguous idea (evaluable but overlaps existing work) is FLAGGED, not auto-proceeded or rejected", () => {
+    const result = assessIdeaFeasibility(
+      { acceptanceHints: ["adds an API key store"] },
+      cleanSignals({ duplicateClusterRisk: "medium" }),
+    );
+    expect(result.disposition).toBe("flag");
+    expect(result.verdict).toBe("raise");
+    expect(result.reasons).toContain("duplicate_cluster_medium");
+  });
+
+  it("an out-of-scope idea whose target repo does not resolve is flagged (target_not_found)", () => {
+    const result = assessIdeaFeasibility(
+      { acceptanceHints: ["do a thing"] },
+      cleanSignals({ targetResolvable: false }),
+    );
+    expect(result.disposition).toBe("flag");
+    expect(result.verdict).toBe("raise");
+    expect(result.issueStatus).toBe("missing");
+    expect(result.reasons).toEqual(expect.arrayContaining(["target_not_found"]));
+  });
+
+  it("surfaces multiple avoid reasons together (already-solved AND duplicate cluster)", () => {
+    const result = assessIdeaFeasibility(
+      { acceptanceHints: ["x"] },
+      cleanSignals({ claimStatus: "solved", duplicateClusterRisk: "high" }),
+    );
+    expect(result.disposition).toBe("reject");
+    expect(result.reasons).toEqual(expect.arrayContaining(["claim_status_solved", "duplicate_cluster_high"]));
+  });
+
+  it("uses an injected verdict composer when provided (test seam), not the engine default", () => {
+    const spy = vi.fn((): FeasibilityGateResult => ({ verdict: "go", avoidReasons: [], raiseReasons: [], summary: "injected" }));
+    const result = assessIdeaFeasibility(
+      { acceptanceHints: ["x"] },
+      cleanSignals(),
+      { buildFeasibilityVerdict: spy },
+    );
+    expect(spy).toHaveBeenCalledWith({
+      found: true,
+      claimStatus: "unclaimed",
+      duplicateClusterRisk: "none",
+      issueStatus: "ready",
+    });
+    expect(result.disposition).toBe("proceed");
+    expect(result.summary).toBe("injected");
+  });
+});