## Thinking Path
> - Paperclip helps people manage AI agents and their work
> - People use the rich markdown editor to write task descriptions,
comments, and agent instructions
> - The editor disables HTML processing, but the markdown parser still
treats some angle-bracket text as HTML
> - A value such as `<name>` could therefore stop the rich editor and
show the raw-source fallback
> - The retry action used the same input, so it could not recover
> - This pull request escapes unsupported angle brackets only while the
editor processes the value
> - The benefit is that the rich editor works and stored markdown stays
unchanged
## Linked Issues or Issue Description
Fixes: #12197
Related prior attempt: #2696
**What happened?**
The rich markdown editor did not start when prose contained a bare angle
bracket, such as `<name>`. It showed the raw-source fallback. The retry
action repeated the same failure.
**Expected behavior**
The rich editor starts for normal prose. It stores the text in its clean
form because agent prompts can use this text.
**Steps to reproduce**
1. Open a task description, comment, or other field that uses the rich
markdown editor.
2. Enter `Rename <name> to the real name`.
3. Reload the field.
4. Observe the raw-source fallback.
**Paperclip version or commit**
`master` at d785b1921.
**Deployment mode**
All modes. The defect is in the UI package.
## What Changed
- Escape only angle brackets that the parser treats as unsupported HTML
constructs.
- Restore the clean markdown before the editor sends a value to its
parent.
- Keep code, autolinks, link destinations, and existing escapes
unchanged.
- Apply the same conversion to pasted and inserted markdown.
- Make the empty-editor fallback wait for editor initialization and
confirm the empty state.
- Re-arm the initial empty-change guard when the user retries the
editor.
- Add `MDE-PARSE`, `MDE-RENDER`, and `MDE-EMPTY` fallback codes.
- Correct the editor mock and add regression tests for parsing, round
trips, paste, insert, retry, and fallback behavior.
## Verification
- `npx vitest run ui/src/lib/angle-bracket-markdown.test.ts
ui/src/lib/blockquote-markdown.test.ts
ui/src/components/MarkdownEditor.test.tsx` — 106 tests passed.
- `pnpm --filter @paperclipai/ui typecheck` — passed.
- `pnpm -r typecheck` — passed.
- `pnpm build` — passed.
- `pnpm check:token-gates` — reports nine existing color findings in
`ui/src/components/onboarding/PillGuy.tsx`. This pull request does not
change that file.
- `pnpm test:run` — the local run found four existing port-allocation
failures in unrelated workspace-runtime tests. The focused editor tests
passed. The pull request CI runs these suites on clean workers.
## Risks
- Low data risk. The conversion applies only while MDXEditor processes a
value. Stored markdown keeps the clean form.
- The scanner skips code, autolinks, link destinations, and existing
escapes to prevent content changes.
- The raw-source fallback can appear about 300 ms later because it now
confirms that the editor stayed empty.
- There is no database or API change.
> For core feature work, check [`ROADMAP.md`](ROADMAP.md) first and
discuss it in `#dev` before opening the PR. Feature PRs that overlap
with planned core work may need to be redirected — check the roadmap
first. See `CONTRIBUTING.md`.
## Model Used
- Original implementation: Anthropic Claude Opus, 1M context, with
agentic tool use in Claude Code.
- PR preparation and verification: OpenAI Codex with GPT-5, reasoning,
code execution, and tool use. 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>
Devin Foley