[nbouliol]

Summary

Rows tied on a non-unique sort column come back in an undefined order, so each OFFSET/LIMIT page can order them differently: list pages and CSV exports repeated some records and dropped others (customer case: 1,366 exported rows, 1,022 distinct ids, sorted by createdDate).

buildPaginated (used by list, list-related, csv, csv-related) now appends the missing primary keys to a non-empty sort, in the direction of the last clause so a composite index (createdDate, id) can still be scanned backward.

 ContextFilterFactory.buildPaginated
-  sort = parseSort(query)
+  sort = parseSort(query)
+  if sort is not empty
+    append sortable primary keys missing from sort, in the last clause's direction

-createdDate          → createdDate DESC, id DESC
-name,createdDate     → name DESC, createdDate ASC, id ASC
createdDate,-id      → unchanged
(no sort)            → unchanged (CSV keeps its own primary-key fallback)

Not in parseSort: authorization reads it to check which fields the caller sorts on.

Evidence

• Before: buildPaginated with sort=-createdDate → [{ createdDate, desc }]
  After: [{ createdDate, desc }, { id, desc }]; covered for composite keys, primary key already in the sort, non-sortable primary key (skipped), empty sort (untouched), and at route level on the CSV export (sort passed to collection.list).

• CSV export run against a local Postgres 16 (CsvGenerator + buildPaginated from this branch, SQL datasource), 5,000 rows with ~90% sharing the same createdAt, exported in chunks of 1,000:

  Sort	Before	After
  -createdAt	5,000 rows, 4,527 distinct ids	createdAt DESC, id DESC → 5,000 rows, 5,000 distinct
  createdAt	5,000 rows, 4,600 distinct ids	createdAt ASC, id ASC → 5,000 rows, 5,000 distinct

  Ties only reorder between pages once the matching rows exceed twice offset + limit (Postgres switches from a full quicksort to a bounded heapsort); 1,500 tied rows did not reproduce it.

Merge Danger

Door: two-way

Pure query-shape change, revert restores the previous behavior.

Blast Radius: sorted-lists

Only the order of rows tied on the sort changes. Every sorted list/export query gets one more ORDER BY key, which can change the query plan on large tables (accepted, no opt-out).

Fixes PRD-1866

🤖 Generated with Claude Code

[linear-code]

PRD-1866

[qltysh]

Coverage Impact

This PR will not change total coverage.

Modified Files with Diff Coverage (1)

Rating	File	% Diff	Uncovered Line #s
	packages/agent/src/utils/context-filter-factory.ts	100.0%
	Total	100.0%

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