diff --git a/autoplan/SKILL.md b/autoplan/SKILL.md
index 5346f1d43..33d589847 100644
--- a/autoplan/SKILL.md
+++ b/autoplan/SKILL.md
@@ -1666,8 +1666,11 @@ if command -v jq >/dev/null 2>&1; then
       # Filter to current branch + recent commits, then keep records for the
       # latest run_id only. (Single phase may have multiple files if the user
       # re-ran the review; aggregator takes the newest.)
+      # Bind the record's .commit to $c BEFORE entering the split-array pipe —
+      # inside ($commits | split("|") | ...) the input is the array, so a bare
+      # index(.commit) would index the array with the string "commit" and error.
       jq -c --arg branch "$BRANCH" --arg commits "$COMMITS_RECENT" \
-        'select(.branch == $branch and ($commits | split("|") | index(.commit) != null))' \
+        'select(.branch == $branch and (.commit as $c | ($commits | split("|") | index($c)) != null))' \
         "$f" 2>/dev/null >> "$ALL_JSONL" || true
     done < <(find "$TASKS_DIR" -maxdepth 1 -name "tasks-$phase-*.jsonl" 2>/dev/null | sort)
     # Reduce to latest run_id per phase
diff --git a/scripts/resolvers/tasks-section.ts b/scripts/resolvers/tasks-section.ts
index 2f86f588b..13bc72d86 100644
--- a/scripts/resolvers/tasks-section.ts
+++ b/scripts/resolvers/tasks-section.ts
@@ -118,8 +118,11 @@ if command -v jq >/dev/null 2>&1; then
       # Filter to current branch + recent commits, then keep records for the
       # latest run_id only. (Single phase may have multiple files if the user
       # re-ran the review; aggregator takes the newest.)
+      # Bind the record's .commit to \$c BEFORE entering the split-array pipe —
+      # inside (\$commits | split("|") | ...) the input is the array, so a bare
+      # index(.commit) would index the array with the string "commit" and error.
       jq -c --arg branch "$BRANCH" --arg commits "$COMMITS_RECENT" \\
-        'select(.branch == $branch and ($commits | split("|") | index(.commit) != null))' \\
+        'select(.branch == $branch and (.commit as $c | ($commits | split("|") | index($c)) != null))' \\
         "$f" 2>/dev/null >> "$ALL_JSONL" || true
     done < <(find "$TASKS_DIR" -maxdepth 1 -name "tasks-$phase-*.jsonl" 2>/dev/null | sort)
     # Reduce to latest run_id per phase
diff --git a/test/autoplan-tasks-aggregator.test.ts b/test/autoplan-tasks-aggregator.test.ts
new file mode 100644
index 000000000..4311a3b84
--- /dev/null
+++ b/test/autoplan-tasks-aggregator.test.ts
@@ -0,0 +1,101 @@
+import { describe, test, expect, beforeAll } from "bun:test";
+import { readFileSync } from "fs";
+import { join } from "path";
+import { spawnSync } from "child_process";
+
+// Regression test for issue #2018: the autoplan Phase 4 aggregator's
+// branch+commit filter used `index(.commit)` INSIDE a `$commits | split("|")`
+// pipe, where the input is the split array, so jq tried to index an array with
+// the string "commit" and errored. The error was swallowed by `2>/dev/null`,
+// so every aggregation silently returned zero tasks.
+//
+// We extract the real `select(...)` filter from the generated autoplan/SKILL.md
+// and run it through jq so this test tracks whatever actually ships, not a copy.
+
+const SKILL = join(import.meta.dir, "..", "autoplan", "SKILL.md");
+
+function hasJq(): boolean {
+  return spawnSync("jq", ["--version"], { encoding: "utf-8" }).status === 0;
+}
+
+function extractSelectFilter(): string {
+  const text = readFileSync(SKILL, "utf-8");
+  // The shipped line looks like:
+  //   'select(.branch == $branch and (.commit as $c | ...))' \
+  const m = text.match(/'(select\(\.branch == \$branch and [^']*\))'/);
+  if (!m) throw new Error("could not find branch+commit select filter in autoplan/SKILL.md");
+  return m[1];
+}
+
+// Run the extracted filter over one JSONL record, returning jq's result.
+function runFilter(filter: string, record: object, branch: string, commits: string) {
+  return spawnSync(
+    "jq",
+    ["-c", "--arg", "branch", branch, "--arg", "commits", commits, filter],
+    { input: JSON.stringify(record), encoding: "utf-8", timeout: 10000 }
+  );
+}
+
+describe("autoplan tasks aggregator branch+commit filter (issue #2018)", () => {
+  let filter: string;
+
+  beforeAll(() => {
+    filter = extractSelectFilter();
+  });
+
+  test("filter does not reference the buggy bare index(.commit)", () => {
+    // The fix binds the record's commit to a variable first; the regression was
+    // an unbound `.commit` evaluated against the split array.
+    expect(filter).not.toContain("index(.commit)");
+    expect(filter).toContain("as $c");
+  });
+
+  test("matching branch + commit is selected (no jq error)", () => {
+    const r = runFilter(
+      filter,
+      { branch: "dev", commit: "abc123", phase: "ceo-review" },
+      "dev",
+      "abc123|def456"
+    );
+    expect(r.status).toBe(0);
+    expect(r.stderr).toBe("");
+    expect(r.stdout.trim()).not.toBe("");
+    expect(JSON.parse(r.stdout).commit).toBe("abc123");
+  });
+
+  test("non-matching commit is excluded (no jq error)", () => {
+    const r = runFilter(
+      filter,
+      { branch: "dev", commit: "zzz999", phase: "ceo-review" },
+      "dev",
+      "abc123|def456"
+    );
+    expect(r.status).toBe(0);
+    expect(r.stderr).toBe("");
+    expect(r.stdout.trim()).toBe("");
+  });
+
+  test("wrong branch is excluded (no jq error)", () => {
+    const r = runFilter(
+      filter,
+      { branch: "other", commit: "abc123", phase: "ceo-review" },
+      "dev",
+      "abc123|def456"
+    );
+    expect(r.status).toBe(0);
+    expect(r.stderr).toBe("");
+    expect(r.stdout.trim()).toBe("");
+  });
+
+  test("record missing commit field does not error, just excludes", () => {
+    const r = runFilter(
+      filter,
+      { branch: "dev", phase: "ceo-review" },
+      "dev",
+      "abc123|def456"
+    );
+    expect(r.status).toBe(0);
+    expect(r.stderr).toBe("");
+    expect(r.stdout.trim()).toBe("");
+  });
+});