diff --git a/packages/gittensory-engine/README.md b/packages/gittensory-engine/README.md
index 380ba0f111..43582fc2a2 100644
--- a/packages/gittensory-engine/README.md
+++ b/packages/gittensory-engine/README.md
@@ -63,3 +63,9 @@ input order.
 `scanAiPolicyText` and `resolveAiPolicyVerdict` provide the deterministic policy gate used by miner discovery.
 They only deny on small, explicit AI-contribution ban phrases in `AI-USAGE.md` or `CONTRIBUTING.md`; ambiguous,
 missing, or empty policy text stays allowed so discovery does not invent a ban.
+
+## MinerGoalSpec
+
+`MinerGoalSpec` is the type surface for a repo's `.gittensory-miner.yml` (miner-side analogue of `.gittensory.yml`).
+`DEFAULT_MINER_GOAL_SPEC` is the safe default a repo with no file behaves as — minable (`minerEnabled: true`, an
+explicit opt-out), no path/label preferences, one concurrent claim, `neutral` discovery. Parsing is a separate module.
diff --git a/packages/gittensory-engine/src/index.ts b/packages/gittensory-engine/src/index.ts
index 031283c159..eb9cdaba6e 100644
--- a/packages/gittensory-engine/src/index.ts
+++ b/packages/gittensory-engine/src/index.ts
@@ -17,3 +17,8 @@ export {
   type AiPolicySource,
   type AiPolicyVerdict,
 } from "./ai-policy-map.js";
+export {
+  DEFAULT_MINER_GOAL_SPEC,
+  type MinerGoalSpec,
+  type MinerIssueDiscoveryPolicy,
+} from "./miner-goal-spec.js";
diff --git a/packages/gittensory-engine/src/miner-goal-spec.ts b/packages/gittensory-engine/src/miner-goal-spec.ts
new file mode 100644
index 0000000000..973bdae566
--- /dev/null
+++ b/packages/gittensory-engine/src/miner-goal-spec.ts
@@ -0,0 +1,66 @@
+// MinerGoalSpec (#2293). The type surface for `.gittensory-miner.yml` — the per-repo config a maintainer/repo-owner
+// drops in to tell an autonomous miner what to look for and how to behave when targeting their repo. This is the
+// MINER-side analogue of the review-side `.gittensory.yml` focus manifest (see `src/signals/focus-manifest.ts`'s
+// `FocusManifest`): a small typed config object paired with an explicit safe-defaults constant.
+//
+// This module is TYPES ONLY — no parsing, no IO. The parser (validation + safe-default coercion of raw YAML) is a
+// separate follow-up issue; keeping the shape small here is deliberate, because it is easy to add a field later and
+// painful to remove one contributors already rely on. Field names/semantics that overlap the review side are
+// carried over verbatim from `.gittensory.yml` so the two manifests stay obviously paired.
+
+/** How strongly opening discovery issues is encouraged for this repo. Mirrors the review-side policy vocabulary. */
+export type MinerIssueDiscoveryPolicy = "encouraged" | "neutral" | "discouraged";
+
+/** Per-repo miner configuration parsed from `.gittensory-miner.yml`. See {@link DEFAULT_MINER_GOAL_SPEC}. */
+export type MinerGoalSpec = {
+  /**
+   * Whether this repo permits autonomous miners at all. Explicit OPT-OUT, not opt-in: a public repo with no
+   * `.gittensory-miner.yml` is still minable, mirroring `.gittensory.yml`'s "safe by default" stance. Set `false`
+   * to halt all miner targeting of this repo. Default: true.
+   */
+  minerEnabled: boolean;
+  /**
+   * Work areas the maintainer wants a miner to focus on; a candidate touching these is preferred. Glob list.
+   * Default: [] (no preference).
+   */
+  wantedPaths: readonly string[];
+  /**
+   * Paths off-limits to a miner. A candidate touching one of these should be skipped. Glob list.
+   * Default: [] (nothing blocked).
+   */
+  blockedPaths: readonly string[];
+  /**
+   * Issue/PR labels the maintainer prefers a miner to target; a candidate carrying one is favored. String list.
+   * Default: [] (no preference).
+   */
+  preferredLabels: readonly string[];
+  /**
+   * Maximum number of issues a single miner may hold claimed on this repo at once, so one miner cannot monopolize
+   * a repo's queue. A positive integer (`>= 1`); the parser is expected to floor a non-integer toward zero
+   * (`Math.floor`) and reject any value below 1. Default: 1.
+   */
+  maxConcurrentClaims: number;
+  /**
+   * How strongly this repo encourages a miner to open discovery issues. Values: encouraged | neutral | discouraged.
+   * Default: neutral.
+   */
+  issueDiscoveryPolicy: MinerIssueDiscoveryPolicy;
+};
+
+/**
+ * The safe defaults applied when a field is absent from `.gittensory-miner.yml` (or the file itself is missing).
+ * Every value here matches the "Default: X" documented on its field above. Analogous to the defaults constant that
+ * accompanies `FocusManifest` in `src/signals/focus-manifest.ts` — a repo with no file behaves as if it declared
+ * this: minable, with no path/label preferences, one concurrent claim, and neutral discovery.
+ *
+ * Deep-frozen: this is a shared singleton, so runtime code can read it freely but must not mutate it — clone before
+ * layering repo-specific overrides on top.
+ */
+export const DEFAULT_MINER_GOAL_SPEC: Readonly<MinerGoalSpec> = Object.freeze({
+  minerEnabled: true,
+  wantedPaths: Object.freeze([]),
+  blockedPaths: Object.freeze([]),
+  preferredLabels: Object.freeze([]),
+  maxConcurrentClaims: 1,
+  issueDiscoveryPolicy: "neutral",
+});
diff --git a/packages/gittensory-engine/test/miner-goal-spec.test.ts b/packages/gittensory-engine/test/miner-goal-spec.test.ts
new file mode 100644
index 0000000000..329b4a933f
--- /dev/null
+++ b/packages/gittensory-engine/test/miner-goal-spec.test.ts
@@ -0,0 +1,56 @@
+// Tests for the MinerGoalSpec type contract (#2293). Types-only module, so these assert (a) the safe-defaults
+// constant's runtime values, (b) that it satisfies the MinerGoalSpec type, and (c) a lightweight "every field is
+// documented with a Default:" lint over the source — not parser behavior (that lands in a separate issue).
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import { DEFAULT_MINER_GOAL_SPEC, type MinerGoalSpec } from "../dist/index.js";
+
+// Compile-time contract: the exported default must satisfy MinerGoalSpec (fails `tsc` if the shape drifts).
+const _contract: MinerGoalSpec = DEFAULT_MINER_GOAL_SPEC;
+void _contract;
+
+test("DEFAULT_MINER_GOAL_SPEC carries the documented safe defaults", () => {
+  assert.deepEqual(DEFAULT_MINER_GOAL_SPEC, {
+    minerEnabled: true, // opt-out, not opt-in: a repo with no file is still minable
+    wantedPaths: [],
+    blockedPaths: [],
+    preferredLabels: [],
+    maxConcurrentClaims: 1,
+    issueDiscoveryPolicy: "neutral",
+  });
+});
+
+test("DEFAULT_MINER_GOAL_SPEC is deep-frozen so the shared singleton can't be mutated", () => {
+  assert.ok(Object.isFrozen(DEFAULT_MINER_GOAL_SPEC));
+  assert.ok(Object.isFrozen(DEFAULT_MINER_GOAL_SPEC.wantedPaths));
+  assert.ok(Object.isFrozen(DEFAULT_MINER_GOAL_SPEC.blockedPaths));
+  assert.ok(Object.isFrozen(DEFAULT_MINER_GOAL_SPEC.preferredLabels));
+});
+
+test("DEFAULT_MINER_GOAL_SPEC exposes exactly the specified field surface", () => {
+  assert.deepEqual(Object.keys(DEFAULT_MINER_GOAL_SPEC).sort(), [
+    "blockedPaths",
+    "issueDiscoveryPolicy",
+    "maxConcurrentClaims",
+    "minerEnabled",
+    "preferredLabels",
+    "wantedPaths",
+  ]);
+});
+
+test("every MinerGoalSpec field is documented with a JSDoc 'Default:' in the source", () => {
+  // The suite compiles to dist-test/ (tsconfig.test.json outDir), a sibling of src/, so ../src/ from this file's
+  // runtime location resolves to the TypeScript source. readFileSync throws loudly if that layout ever changes, so
+  // this test can't silently pass on a bad path.
+  const source = readFileSync(new URL("../src/miner-goal-spec.ts", import.meta.url), "utf8");
+  const escapeRe = (s: string): string => s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+  for (const field of Object.keys(DEFAULT_MINER_GOAL_SPEC)) {
+    // Grab the JSDoc block immediately preceding the field declaration inside the type. Field names are escaped
+    // before interpolation so the pattern stays safe if it is ever reused for a less controlled field surface.
+    const doc = source.match(new RegExp(`(/\\*\\*[\\s\\S]*?\\*/)\\s*\\n\\s*${escapeRe(field)}:`));
+    const jsdoc = doc?.[1];
+    assert.ok(jsdoc, `field '${field}' should have a JSDoc block`);
+    assert.match(jsdoc, /Default:/, `field '${field}' JSDoc should state its Default:`);
+  }
+});