FN-6629: Lower task-list text budget

Keep fn_task_list responses below host text imageification thresholds.\n\n- Lower the shared task-list text clamp to a 3,000 character host-safe budget.\n- Reuse the shared budget in CLI, dashboard, and engine fallback formatters.\n- Cover realistic column-filtered fn_task_list outputs and fallback budget behavior with regression tests.\n- Add a patch changeset for the published Fusion package.\n\nFiles changed:\n .changeset/fn-6629-task-list-budget.md             |  5 ++\n packages/cli/src/__tests__/extension.test.ts       | 88 ++++++++++++++++++++++\n packages/cli/src/extension.ts                      |  7 +-\n .../core/src/__tests__/task-list-format.test.ts    | 25 ++++++\n packages/core/src/task-list-format.ts              |  5 +-\n .../src/__tests__/planning-board-tools.test.ts     |  4 +-\n packages/dashboard/src/planning-board-tools.ts     |  8 +-\n packages/engine/src/__tests__/triage.test.ts       |  4 +-\n packages/engine/src/triage.ts                      |  7 +-\n 9 files changed, 144 insertions(+), 9 deletions(-)

Fusion-Task-Id: FN-6629

Fusion-Task-Lineage: 6ec7cd33-d4e5-4c12-8512-c3823a9dfb3e

.changeset/fn-6629-task-list-budget.md

@@ -0,0 +1,5 @@
+---
+"@runfusion/fusion": patch
+---
+
+Lower the shared `fn_task_list` plain-text budget and cover filtered column listings with realistic regression cases so large todo, planning, and done outputs stay host-safe.

packages/cli/src/__tests__/extension.test.ts

@@ -2552,11 +2552,18 @@ describe("fn pi extension (runnable structured-output regression slice)", () =>
   });
 
   describe("fn_task_list", () => {
+    const HOST_SAFE_TASK_LIST_TEXT_CEILING = 3_000;
+
     function expectSingleBoundedTextBlock(result: any) {
       expect(result.content).toHaveLength(1);
       expect(result.content[0].type).toBe("text");
       expect(result.content[0].text).toBeTruthy();
       expect(result.content[0].text.length).toBeLessThanOrEqual(MAX_TASK_LIST_TEXT_CHARS);
+      expect(result.content[0].text.length).toBeLessThanOrEqual(HOST_SAFE_TASK_LIST_TEXT_CEILING);
+    }
+
+    function realisticTaskTitle(column: string, index: number) {
+      return `${column} realistic task ${String(index).padStart(3, "0")} keeps enough descriptive context for text agents without artificial padding`;
     }
 
     it("returns bounded text for omitted and provided column/limit params", async () => {
@@ -2612,6 +2619,87 @@ describe("fn pi extension (runnable structured-output regression slice)", () =>
       expect(result.details.count).toBe(2);
     });
 
+    it("bounds realistic column-filtered listings below the host-safe text budget", async () => {
+      const store = new TaskStore(tmpDir);
+      await store.init();
+      try {
+        const todoFirst = await store.createTask({
+          title: realisticTaskTitle("todo", 1),
+          description: "Realistic todo task 001",
+          column: "todo",
+        });
+        for (let i = 2; i <= 60; i += 1) {
+          await store.createTask({
+            title: realisticTaskTitle("todo", i),
+            description: `Realistic todo task ${String(i).padStart(3, "0")}`,
+            column: "todo",
+            dependencies: [todoFirst.id],
+          });
+        }
+        for (let i = 1; i <= 35; i += 1) {
+          await store.createTask({
+            title: realisticTaskTitle("triage", i),
+            description: `Realistic triage task ${String(i).padStart(3, "0")}`,
+          });
+        }
+        for (let i = 1; i <= 30; i += 1) {
+          await store.createTask({
+            title: realisticTaskTitle("done", i),
+            description: `Realistic done task ${String(i).padStart(3, "0")}`,
+            column: "done",
+          });
+        }
+      } finally {
+        store.close();
+      }
+
+      const listTool = api.tools.get("fn_task_list")!;
+      const broadResult = await listTool.execute(
+        "list-realistic-broad",
+        { limit: 20 },
+        undefined,
+        undefined,
+        makeCtx(tmpDir),
+      );
+      expectSingleBoundedTextBlock(broadResult);
+      expect(broadResult.content.some((block: any) => block.type === "image")).toBe(false);
+      expect(broadResult.content[0].text).toContain("Planning (35):");
+      expect(broadResult.details.count).toBe(125);
+
+      for (const { callId, params, header, ids } of [
+        {
+          callId: "list-realistic-todo",
+          params: { column: "todo", limit: 50 },
+          header: "Todo (60):",
+          ids: ["FN-001", "FN-002"],
+        },
+        {
+          callId: "list-realistic-triage",
+          params: { column: "triage", limit: 50 },
+          header: "Planning (35):",
+          ids: ["FN-061", "FN-062"],
+        },
+        {
+          callId: "list-realistic-done",
+          params: { column: "done", limit: 50 },
+          header: "Done (30):",
+          ids: ["FN-096", "FN-097"],
+        },
+      ] as const) {
+        const result = await listTool.execute(callId, params, undefined, undefined, makeCtx(tmpDir));
+        const text = result.content[0].text;
+
+        expectSingleBoundedTextBlock(result);
+        expect(result.content.some((block: any) => block.type === "image")).toBe(false);
+        expect(text).toContain(header);
+        for (const id of ids) {
+          expect(text).toContain(id);
+        }
+        expect(text).toContain("truncated to fit; narrow with column/limit");
+        expect(result.details.count).toBe(125);
+      }
+    });
+
     it("bounds broad listings as a single plain-text block", async () => {
       const store = new TaskStore(tmpDir);
       await store.init();

packages/cli/src/extension.ts

@@ -26,6 +26,7 @@ import {
   getTaskDuplicateLineage,
   resolveAgentProvisioningPolicy,
   TASK_PRIORITIES,
+  MAX_TASK_LIST_TEXT_CHARS,
   resolveSecretAccessPolicy,
   getProjectRootFromWorktree,
   resolveTaskGithubTracking,
@@ -69,7 +70,11 @@ export function inlineTaskListFallback(
   lines: string[],
   opts: { maxChars?: number } = {},
 ): string {
-  const maxChars = Math.max(1, Math.floor(opts.maxChars ?? 12_000));
+  /*
+  FNXC:TaskListOutput 2026-06-18-03:20:
+  FN-6629 requires stale-runtime fallback formatting to mirror the shared host-safe task-list budget; otherwise missing @fusion/core formatter exports can re-emit imageified column-filtered listings.
+  */
+  const maxChars = Math.max(1, Math.floor(opts.maxChars ?? MAX_TASK_LIST_TEXT_CHARS));
   try {
     const text = lines.join("\n");
     if (text.length <= maxChars) {

packages/core/src/__tests__/task-list-format.test.ts

@@ -201,6 +201,10 @@ describe("formatTaskListText", () => {
 });
 
 describe("clampTaskListText", () => {
+  it("documents the host-safe default budget", () => {
+    expect(MAX_TASK_LIST_TEXT_CHARS).toBe(3_000);
+  });
+
   it("returns an empty string for empty input", () => {
     expect(clampTaskListText([])).toBe("");
   });
@@ -264,6 +268,27 @@ describe("clampTaskListText", () => {
     expect(clampTaskListText(lines).length).toBeLessThanOrEqual(MAX_TASK_LIST_TEXT_CHARS);
   });
 
+  it("truncates realistic large listings under the host-safe budget", () => {
+    const lines = [
+      "Todo (60):",
+      ...Array.from(
+        { length: 50 },
+        (_, index) =>
+          `  FN-${String(index + 1).padStart(3, "0")}  Realistic todo task ${String(index + 1).padStart(3, "0")} keeps descriptive context for text agents without artificial padding`,
+      ),
+      "  ... and 10 more",
+      "",
+    ];
+
+    const text = clampTaskListText(lines);
+
+    expect(lines.join("\n").length).toBeGreaterThan(MAX_TASK_LIST_TEXT_CHARS);
+    expect(text.length).toBeLessThanOrEqual(MAX_TASK_LIST_TEXT_CHARS);
+    expect(text).toContain("Todo (60):");
+    expect(text).toContain("FN-001");
+    expect(text).toContain("truncated to fit; narrow with column/limit");
+  });
+
   it("handles a single over-budget line by returning a bounded truncation marker", () => {
     const text = clampTaskListText(["FN-001  " + "x".repeat(200)], { maxChars: 40 });
 

packages/core/src/task-list-format.ts

@@ -1,4 +1,4 @@
-export const MAX_TASK_LIST_TEXT_CHARS = 12_000;
+export const MAX_TASK_LIST_TEXT_CHARS = 3_000;
 
 const TRUNCATION_HINT = "truncated to fit; narrow with column/limit";
 
@@ -14,6 +14,9 @@ function joinWithMarker(lines: string[], marker: string): string {
  * FNXC:TaskListOutput 2026-06-16-17:45:
  * FN-6492 requires every fn_task_list surface to emit bounded plain text so column-filtered or otherwise large board listings remain readable to text-only heartbeat agents and stay below host runtimes' imageification thresholds.
  * The default budget is intentionally below common MCP attachment-conversion limits while preserving dozens of compact task rows.
+ *
+ * FNXC:TaskListOutput 2026-06-18-03:12:
+ * FN-6629 lowers the budget from 12,000 because realistic column-filtered heartbeat listings stayed under that old clamp while still exceeding the host imageification threshold. Keep the bound in the low-thousands so todo/triage/done limit-50 outputs remain text-only for heartbeat and other text agents.
  */
 export function clampTaskListText(
   lines: string[],

packages/dashboard/src/__tests__/planning-board-tools.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it, vi } from "vitest";
-import type { TaskStore } from "@fusion/core";
+import { MAX_TASK_LIST_TEXT_CHARS, type TaskStore } from "@fusion/core";
 import { createPlanningBoardTools, resolveTaskListFormatter } from "../planning-board-tools.js";
 
 function createStoreMock(overrides?: {
@@ -33,7 +33,7 @@ describe("fn_task_list resilience (FN-6573)", () => {
       const formatter = resolveTaskListFormatter(coreNamespace);
       const text = formatter(boardLines, { clamp: coreNamespace.clampTaskListText }).trimEnd();
       expect(text).toBeTruthy();
-      expect(text.length).toBeLessThanOrEqual(12_000);
+      expect(text.length).toBeLessThanOrEqual(MAX_TASK_LIST_TEXT_CHARS);
     }
   });
 });

packages/dashboard/src/planning-board-tools.ts

@@ -1,5 +1,5 @@
 import * as fusionCore from "@fusion/core";
-import type { TaskStore } from "@fusion/core";
+import { MAX_TASK_LIST_TEXT_CHARS, type TaskStore } from "@fusion/core";
 import type { ToolDefinition } from "@earendil-works/pi-coding-agent";
 
 type TaskListClamp = (lines: string[], opts?: { maxChars?: number }) => string;
@@ -12,7 +12,11 @@ export function inlineTaskListFallback(
   lines: string[],
   opts: { maxChars?: number } = {},
 ): string {
-  const maxChars = Math.max(1, Math.floor(opts.maxChars ?? 12_000));
+  /*
+  FNXC:TaskListOutput 2026-06-18-03:20:
+  FN-6629 requires stale-runtime fallback formatting to mirror the shared host-safe task-list budget; otherwise missing @fusion/core formatter exports can re-emit imageified board listings.
+  */
+  const maxChars = Math.max(1, Math.floor(opts.maxChars ?? MAX_TASK_LIST_TEXT_CHARS));
   try {
     const text = lines.join("\n");
     if (text.length <= maxChars) {

packages/engine/src/__tests__/triage.test.ts

@@ -1,6 +1,6 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 import type { TaskStore, Task, TaskDetail, Settings } from "@fusion/core";
-import { builtinSeamPrompt, renderTriagePolicyPlaceholders, resolveAgentPrompt } from "@fusion/core";
+import { builtinSeamPrompt, MAX_TASK_LIST_TEXT_CHARS, renderTriagePolicyPlaceholders, resolveAgentPrompt } from "@fusion/core";
 import {
   TriageProcessor,
   buildSpecificationPrompt,
@@ -62,7 +62,7 @@ describe("fn_task_list resilience (FN-6573)", () => {
       const formatter = resolveTaskListFormatter(coreNamespace);
       const text = formatter(boardLines, { clamp: coreNamespace.clampTaskListText }).trimEnd();
       expect(text).toBeTruthy();
-      expect(text.length).toBeLessThanOrEqual(12_000);
+      expect(text.length).toBeLessThanOrEqual(MAX_TASK_LIST_TEXT_CHARS);
     }
   });
 });

packages/engine/src/triage.ts

@@ -27,6 +27,7 @@ import {
   findNearDuplicates,
   isNearDuplicateCanonicalInactive,
   applyFrontendUxCriteria,
+  MAX_TASK_LIST_TEXT_CHARS,
   type NearDuplicateCandidate,
 } from "@fusion/core";
 
@@ -40,7 +41,11 @@ export function inlineTaskListFallback(
   lines: string[],
   opts: { maxChars?: number } = {},
 ): string {
-  const maxChars = Math.max(1, Math.floor(opts.maxChars ?? 12_000));
+  /*
+  FNXC:TaskListOutput 2026-06-18-03:20:
+  FN-6629 requires stale-runtime fallback formatting to mirror the shared host-safe task-list budget; otherwise missing @fusion/core formatter exports can re-emit imageified duplicate-check listings.
+  */
+  const maxChars = Math.max(1, Math.floor(opts.maxChars ?? MAX_TASK_LIST_TEXT_CHARS));
   try {
     const text = lines.join("\n");
     if (text.length <= maxChars) {