Fix Markdown in provisional task titles (#15047)

## Thinking Path

> - Paperclip uses issues to organize work for AI agents.
> - Paperclip creates a provisional issue title from the issue
description.
> - A description can start with a Markdown image or other Markdown
syntax.
> - The old title logic truncated the raw Markdown source.
> - This pull request parses Markdown before it truncates the title.
> - The benefit is a short and readable provisional title.

## Linked Issues or Issue Description

**What happened?**

When an issue description started with a Markdown image, Paperclip used
the raw image syntax and URL in the provisional title. Other common
Markdown markers could also appear in the title.

**Expected behavior**

Paperclip must remove Markdown syntax before it creates the
120-character provisional title. It must keep useful text, such as link
labels and inline code content.

**Steps to reproduce**

1. Create an issue without an explicit title.
2. Start the issue description with a Markdown image.
3. Add Markdown text after the image.
4. Observe that the provisional title contains raw Markdown syntax or an
image URL.

**Paperclip version or commit**

The problem reproduces on `master` before this change.

**Deployment mode**

Local development with the embedded PGlite database.

## What Changed

- Parse the description and remove image nodes before title generation.
- Convert the remaining Markdown to plain text before the 120-character
limit.
- Keep link labels, inline code, and identifier punctuation.
- Use image alt text, or `Image`, for an image-only description.
- Fall back to a simple 120-character title if Markdown parsing or
conversion fails.
- Add regression tests for image and inline-code titles, parser
failures, and text-conversion failures.

## Verification

- `./node_modules/.bin/vitest run
server/src/__tests__/task-title-routes.test.ts`
- `./node_modules/.bin/tsc -p server/tsconfig.json --noEmit`
- Full GitHub CI matrix passed on commit
`663f3a0517c9e450f174b6c37970756457067ba5`.
- Greptile reviewed the latest commit with a 5/5 confidence score and no
unresolved findings.

## Risks

- Low risk. This change only affects generated provisional titles. It
does not change explicit titles or full issue descriptions.
- The implementation uses the Markdown parser and plain-text converter
that are already present in the server.

> This is a focused bug fix. It does not add planned core work from
`ROADMAP.md`.

## Model Used

- OpenAI Codex with GPT-5. The run used reasoning, tool use, code
execution, and repository access. The runtime did not expose the context
window size.

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [x] I have not referenced internal/instance-local Paperclip issues or
links (only public GitHub `#NNN` / `github.com/paperclipai/paperclip`
URLs)
- [x] My branch name describes the change (e.g. `docs/...`, `fix/...`)
and contains no internal Paperclip ticket id or instance-derived details
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] All Paperclip CI gates are green
- [x] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge

---------

Co-authored-by: Paperclip <noreply@paperclip.ing>

server/src/__tests__/task-title-routes.test.ts

@@ -1,5 +1,15 @@
 import { randomUUID } from "node:crypto";
-import { afterAll, beforeAll, describe, expect, it } from "vitest";
+import { afterAll, beforeAll, describe, expect, it, vi } from "vitest";
+import * as chat from "chat";
+
+vi.mock("chat", async importOriginal => {
+  const original = await importOriginal<typeof import("chat")>();
+  return {
+    ...original,
+    parseMarkdown: vi.fn(original.parseMarkdown),
+    markdownToPlainText: vi.fn(original.markdownToPlainText),
+  };
+});
 import { and, eq } from "drizzle-orm";
 import { activityLog, externalObjectMentions, heartbeatRuns, issues } from "@paperclipai/db";
 import { createChildIssueSchema, createIssueSchema, setIssueTitleSchema } from "@paperclipai/shared";
@@ -49,6 +59,52 @@ describe("task titles", () => {
     expect(setIssueTitleSchema.safeParse({ title: "x".repeat(241) }).success).toBe(false);
   });
 
+  it("removes leading Markdown before truncating a provisional title", async () => {
+    const f = await server.fixture();
+    const description = [
+      "![Screenshot](https://example.com/a-very-long-image-name.png)",
+      "# Fix the [sign-in redirect](https://example.com/issues/42)",
+      "Keep `returnTo` working with **saved sessions**.",
+    ].join("\n\n");
+    const result = await issueService(server.db).create(f.companyId, { description });
+    expect(result).toMatchObject({
+      title: "Fix the sign-in redirect Keep returnTo working with saved sessions.",
+      description,
+      titleNeedsGeneration: true,
+    });
+    await expect(issueService(server.db).create(f.companyId, {
+      description: "![Error dialog](https://example.com/error.png)",
+    })).resolves.toMatchObject({ title: "Error dialog", titleNeedsGeneration: true });
+    await expect(issueService(server.db).create(f.companyId, {
+      description: "![](https://example.com/image.png)",
+    })).resolves.toMatchObject({ title: "Image", titleNeedsGeneration: true });
+    await expect(issueService(server.db).create(f.companyId, {
+      description: "![Map](https://example.com/Map_(1).png)",
+    })).resolves.toMatchObject({ title: "Map", titleNeedsGeneration: true });
+    await expect(issueService(server.db).create(f.companyId, {
+      description: "Fix `set_task_title`",
+    })).resolves.toMatchObject({ title: "Fix set_task_title", titleNeedsGeneration: true });
+    await expect(issueService(server.db).create(f.companyId, {
+      description: "![Screenshot][img]\n\n[img]: https://example.com/image.png\n\nFix login",
+    })).resolves.toMatchObject({ title: "Fix login", titleNeedsGeneration: true });
+  });
+
+  it.each(["parseMarkdown", "markdownToPlainText"] as const)("falls back to a simple title if %s throws", async parser => {
+    const f = await server.fixture();
+    const description = `  Fix the login flow after a failed parser\n${"long ".repeat(30)}`;
+    vi.mocked(chat[parser]).mockImplementationOnce(() => { throw new Error("parser failed"); });
+    try {
+      const result = await issueService(server.db).create(f.companyId, { description });
+      expect(result).toMatchObject({
+        title: description.trim().replace(/\s+/g, " ").slice(0, 120),
+        description,
+        titleNeedsGeneration: true,
+      });
+    } finally {
+      vi.mocked(chat[parser]).mockClear();
+    }
+  });
+
   it("creates prompt-only children and still accepts explicit child titles", async () => {
     const f = await server.fixture();
     const description = "Investigate the child sign-in redirect";

server/src/services/issues.ts

@@ -9,6 +9,7 @@ import { executionProjectionsForRuns } from "./execution-projection.js";
 import type { ExecutionProjection } from "@paperclipai/shared";
 import { Buffer } from "node:buffer";
 import { createHash, randomUUID } from "node:crypto";
+import { markdownToPlainText, parseMarkdown } from "chat";
 import {
   and,
   asc,
@@ -6621,6 +6622,40 @@ export function issueService(db: Db) {
   const instanceSettings = instanceSettingsService(db);
   const treeControlSvc = issueTreeControlService(db);
 
+  function provisionalTitleFromDescription(description: string) {
+    const simpleTitle = description.trim().replace(/\s+/g, " ").slice(0, 120);
+    try {
+      type MarkdownNode = {
+        type: string;
+        alt?: string | null;
+        children?: MarkdownNode[];
+        position?: { start: { offset?: number }; end: { offset?: number } };
+      };
+      const imageRanges: Array<{ start: number; end: number }> = [];
+      const imageAlts: string[] = [];
+      const visit = (node: MarkdownNode) => {
+        if (node.type === "image" || node.type === "imageReference") {
+          const start = node.position?.start.offset;
+          const end = node.position?.end.offset;
+          if (start !== undefined && end !== undefined) imageRanges.push({ start, end });
+          if (node.alt?.trim()) imageAlts.push(node.alt.trim());
+        }
+        node.children?.forEach(visit);
+      };
+      visit(parseMarkdown(description) as MarkdownNode);
+      const withoutImages = imageRanges
+        .sort((a, b) => b.start - a.start)
+        .reduce((text, range) => `${text.slice(0, range.start)} ${text.slice(range.end)}`, description);
+      const plainText = markdownToPlainText(withoutImages).trim().replace(/\s+/g, " ");
+      const fallback = imageRanges.length > 0
+        ? imageAlts.join(" ") || "Image"
+        : simpleTitle;
+      return (plainText || fallback).slice(0, 120);
+    } catch {
+      return simpleTitle;
+    }
+  }
+
   function normalizeCreateIssueTitle(title: string) {
     return title.trim().replace(/\s+/g, " ").toLowerCase();
   }
@@ -9759,7 +9794,9 @@ export function issueService(db: Db) {
         ...issueData
       } = data;
       const explicitTitle = issueData.title?.trim();
-      const provisionalTitle = issueData.description?.trim().replace(/\s+/g, " ").slice(0, 120);
+      const provisionalTitle = issueData.description
+        ? provisionalTitleFromDescription(issueData.description)
+        : undefined;
       const resolvedTitle = explicitTitle || provisionalTitle;
       if (!resolvedTitle) throw unprocessable("Provide a title or task description");
       const titleNeedsGeneration = !explicitTitle;