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## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work.
> - Agents update tasks through the issue API.
> - The update response did not state which values changed.
> - Blocker updates also did not echo the scalar blocker IDs.
> - Agents therefore used an extra GET request to confirm a successful
write.
> - This pull request adds an authoritative change receipt and an
optional small response.
> - The benefit is fewer API calls with a clear and compatible write
contract.
## Linked Issues or Issue Description
No public GitHub issue exists for this change.
### Subsystem affected
Cross-cutting: `server/`, `packages/shared`, and the UI issue cache.
### Problem or motivation
A successful issue PATCH returned the updated issue, but it did not
identify the effective changes. Blocker writes returned relation
summaries without the scalar IDs. Agents could not distinguish a
confirmed clear operation from missing data. The response must confirm
committed field and blocker changes while existing UI clients continue
to receive the full issue by default.
### Proposed solution
Add a `changes` receipt. Add a conditional `blockedByIssueIds` echo.
Support `Prefer: return=minimal`. Keep the full response as the default.
### Alternatives considered
Make the small response the default for agent tokens. This would create
different response contracts by actor type, so this pull request does
not use that design.
### Roadmap alignment
This is a focused control-plane reliability improvement. It does not
duplicate an open roadmap milestone.
## What Changed
- Compute committed issue row and relation changes in the issue service.
- Omit no-op fields and truncate changed long text values to 200
characters.
- Echo blocker ID arrays for blocker set and clear requests.
- Add the opt-in `Prefer: return=minimal` response and
`Preference-Applied` header.
- Keep receipt metadata out of React Query issue caches.
- Add route and embedded Postgres tests for the new contract.
## Verification
- `pnpm exec vitest run
server/src/__tests__/issue-activity-events-routes.test.ts`
- `pnpm exec vitest run server/src/__tests__/issues-service.test.ts -t
"returns authoritative update receipts for row fields and blocker
relations"`
- `pnpm --filter @paperclipai/shared typecheck`
- `pnpm --filter @paperclipai/server typecheck`
- `pnpm --filter @paperclipai/ui typecheck`
- `pnpm check:token-gates`
- `git diff --check`
## Risks
- Low compatibility risk. The default response only adds receipt fields.
- Minimal mode is opt-in. Existing clients do not receive a smaller
body.
- The receipt excludes `updatedAt` because the response already returns
it as the freshness anchor.
- Prose API and agent workflow guidance will follow after the server
contract is available.
> 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
- OpenAI Codex based on GPT-5. The exact deployment ID, context window
size, and reasoning mode are not exposed to the agent. The agent used
repository tools, code execution, and test execution.
## 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
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Co-authored-by: Paperclip <noreply@paperclip.ing>
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