fix(traces): stop the segment guard zeroing multi-line commands

[saksharthakkar]

Motivation

PR #2836's segment guard stops at any newline, so every backslash-continued command scores 0 — skill-platform-traces-feedback-list-filters fell from 1.00 to 0.00 on Claude with identical agent behavior. Dropping the \n term restores multi-line matching without giving back the batched-call fix #2836 was written for.

Summary

The command_executed segment guard scopes a lookahead to "the rest of THIS command":

OLD:  (?:(?!\n|&&|\|\||;|\||\s(?:uip|$UIP)\s).)*
NEW:  (?:(?!&&|\|\||;|\||\s(?:uip|$UIP)\s)[\s\S])*

The safety net assumed in the #2836 review does not exist. coder_eval matches a raw haystack and a shlex-normalized one, but normalization does not collapse a backslash line continuation:

>>> shlex.split("a \\\n b", posix=True)
['a', '\n', 'b']

The escaped newline survives as a literal '\n' token and " ".join(tokens) puts it straight back — now as a bare newline. Both haystacks keep the line break, so every lookahead dies at the first continuation.

Run evidence

Run	Task	Command shape	Score
2026-08-27_04-13-44 (last pre-#2836)	skill-platform-traces-feedback-list-filters	2/2 multi-line	1.00
2026-08-31_04-15-47 (post-#2836)	same task	same 2/2 multi-line	0.00 / 3

Identical agent behavior; #2836 alone flipped it. All three commands in the 08-31 run were correct — just backslash-continued. The sibling task skill-platform-traces-feedback-list-detailed scored 1.00 in the same run only because its commands happened to be single-line; it carries the same latent bug, so both files are fixed here.

Codex is unaffected and keeps the fix it needed: it writes single-line commands and went 6-fail/9 pre-#2836 to 3/3 pass post-#2836.

Why (?<!\\)\n is not enough

A lookbehind that skips only escaped newlines repairs the raw haystack but not the normalized one, where \ + newline has already become a bare newline. That mis-splits one merged command into two fake segments and opens a false positive: control B2 below is a single merged command carrying both --span-id and --agent-id, and the criterion that must reject it starts passing. The \n term buys no scoping that \s(?:uip|$UIP)\s does not already provide, so the fix is to remove it rather than narrow it.

File-by-file

• tests/tasks/uipath-platform/traces/traces_feedback_list_filters_smoke.yaml — all 3 command_pattern regexes moved to the new guard (8 guard occurrences). The task description no longer claims the lookahead stops at a newline.
• tests/tasks/uipath-platform/traces/traces_feedback_list_detailed_smoke.yaml — same, all 3 command_pattern regexes (7 guard occurrences). No behavior change today (its commands were single-line), but it removes the latent zero.
• tests/scripts/test_command_pattern_segment_guard.py (new) — replays a 7-control matrix in single-line and multi-line shape through a faithful copy of coder_eval 0.11.5 _match_haystacks / _normalize_shell (raw + shlex-normalized haystacks, re.DOTALL). It reads the shipped regexes out of the task YAML, so it fails red if the \n term ever comes back, and it pins both rejected alternatives.
• tests/README.md — corrects the segment-scoping rule: it claimed the grader "also matches a normalized haystack with newlines collapsed to spaces", which is what made the fix(traces): segment-scope list_* graders; stop gating on default sort order #2836 review look sound. Now states the corrected guard and that continuations are not collapsed.
• .github/workflows/test-helpers.yml — new command-pattern-guard job running the matrix, plus tests/tasks/uipath-platform/** added to the trigger paths so editing the guarded YAMLs re-runs it.

Control matrix

Every control runs in both a single-line and a multi-line (backslash-continued) shape — 14 cells, 42 criterion outcomes.

#	Control	Expected
A	correct 2-call trajectory	PASS
B	both filters merged into ONE command	FAIL c1 only
B2	merged, line break between --span-id and --agent-id	FAIL c1 only
C	--offset 10 (page number, not zero-based offset)	FAIL c3 only
D	span read done via list detailed	FAIL c1 only
E	two reads chained with && in one call	PASS
F	two reads stacked on separate newlines in one call	PASS

Guard	Mismatching cells
OLD (currently on main)	7 — every multi-line shape wrongly zeroed (18 of 42 criterion outcomes wrong)
(?<!\\)\n variant	1 — B2 multi-line, where c1 wrongly passes a merged command
proposed (no \n term)	0

E and F stay green, so #2836's batched-call fix is preserved.

The plan for this change predicted 2 mismatches for the (?<!\\)\n variant; the measured matrix produces 1. The hole is the same one (the merged-command false positive) — only the cell count differs, because the single-line rendering of B2 is identical to B and grades correctly.

Tests performed

$ python3 -m pytest tests/scripts/test_command_pattern_segment_guard.py -q
19 passed in 0.03s

$ python3 -m pytest tests/scripts/ -q
122 passed in 29.29s

$ python3 scripts/check-task-driver.py tests/tasks
OK — no task pins `sandbox.driver: tempdir`.

$ python3 scripts/check-cli-verbs.py \
    tests/tasks/uipath-platform/traces/traces_feedback_list_filters_smoke.yaml \
    tests/tasks/uipath-platform/traces/traces_feedback_list_detailed_smoke.yaml
OK — no CLI-verb issues (catalog: uip 1.202.0-dev.8414, 1555 verbs).

Plus a YAML parse and re.compile(..., re.DOTALL) over every command_pattern in tests/tasks/uipath-platform/traces/ (11 files, 30 patterns — all compile), and a YAML parse of the edited workflow.

scripts/check-skill-verbs.py was not run: it takes a skill directory and this PR changes no skill under skills/ or preview/.

The two graded tasks were not re-run end to end against a tenant — a live run needs credentials this change does not affect. The change is to the grader regex only, and the control matrix replays the exact scoring path (_match_haystacks + re.DOTALL search) that a live run would take, including the two real command shapes recorded in runs 2026-08-27_04-13-44 and 2026-08-31_04-15-47.

Test plan

• All 6 command_pattern regexes in both traces task YAMLs use the continuation-safe guard
• git grep -F '(?!\n|&&' -- tests/tasks/ returns nothing
• 7-control matrix passes in single-line and multi-line shape under the shipped guard
• Old guard and the (?<!\\)\n variant are pinned as failing, so neither can quietly return
• Batched-call controls (E &&, F stacked lines) still grade per command
• Existing tests/scripts/ suite unchanged and green
• Next nightly Claude run scores skill-platform-traces-feedback-list-filters above 0

LLMOPS-3152

🤖 Generated with Claude Code

[github-actions]

Claude finished @saksharthakkar's task in 1m 51s —— View job

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Coder-eval task lint (advisory)

2 task YAMLs changed; verdict counts: 0 Critical, 0 High, 0 Medium, 0 Low, 2 OK.

Rubric: .claude/commands/lint-task.md. This check is advisory and never blocks merge.

Evidence of passing run

❌ High — PR body explicitly states "The two graded tasks were not re-run end to end against a tenant" and the test-plan item "Next nightly Claude run scores skill-platform-traces-feedback-list-filters above 0" is unchecked.

The author does provide strong indirect evidence: a 7-control × 2-shape matrix test (test_command_pattern_segment_guard.py, 19 passed) that replays the exact _match_haystacks + re.DOTALL scoring path coder-eval takes, plus run data from 2026-08-27_04-13-44 (pre-regression) and 2026-08-31_04-15-47 (post-regression) demonstrating the failure. Given the change is regex-only and the control matrix is comprehensive, this is a reasonable substitute — but per convention, please consider adding a line to the PR description confirming the tasks pass once the next nightly lands, e.g.: Ran skill-platform-traces-feedback-list-filters locally and it passed.

Per-task lint

tests/tasks/uipath-platform/traces/traces_feedback_list_filters_smoke.yaml — verdict: OK

All three command_executed criteria use segment-scoped lookaheads with substantive flag-combination checks (span scoping with --span-id but not --agent-id; sentiment + agent attribution; pagination with exact --limit 5 --offset 5). No self-report, no over-specification, no gameability. Well-differentiated from all five nearest siblings (traces_feedback_smoke, _mutate_smoke, _negative_smoke, _comment_file_smoke, _list_detailed_smoke) — each tests a distinct operation surface.

tests/tasks/uipath-platform/traces/traces_feedback_list_detailed_smoke.yaml — verdict: OK

Three command_executed criteria cover time-window filters (--since 24h, --after/--before), category scoping, and sort-order negative assertion. The file_contains check on detailed.json for '"Result"' (weight 1.0) validates the CLI response envelope — low-weight supplementary check alongside the primary command-shape criteria (weight 2.0–2.5). Not a near-duplicate of the filters task: different subcommand (list detailed vs list), different filter surface, different assertions.

Within-PR duplicates

No duplicate clusters detected. Both tasks test distinct subcommands with different filter surfaces.

Conclusion

✅ All changed tasks pass the rubric. Evidence of passing run is pending the next nightly — the control matrix test provides strong interim coverage for a regex-only change.

[github-actions]

Claude finished @saksharthakkar's task in 2m 41s —— View job

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Summary

Fixes a regression from PR #2836 where the command_executed segment guard stopped at any \n, zeroing every backslash-continued command. The fix removes \n from the guard's stop list and changes . to [\s\S] for explicit newline matching, while preserving the batched-call scoping that #2836 introduced. A thorough 7-control × 2-shape test matrix pins the fix and prevents reintroduction.

Change-by-Change Review

1. tests/tasks/uipath-platform/traces/traces_feedback_list_filters_smoke.yaml

Severity: OK

All 3 command_pattern regexes (8 guard occurrences) correctly updated: \n removed from the negative lookahead, . changed to [\s\S]. The description field at line 10 is also corrected to no longer claim the guard stops at newlines. The patterns are consistent and compile under re.DOTALL.

2. tests/tasks/uipath-platform/traces/traces_feedback_list_detailed_smoke.yaml

Severity: OK

Same mechanical guard update across all 3 command_pattern regexes (7 guard occurrences). No behavioral change today (its commands were single-line in recorded runs), but removes the latent scoring bug. Consistent with the filters task.

3. tests/scripts/test_command_pattern_segment_guard.py (new, 211 lines)

Severity: OK

Well-structured regression test. Key strengths:

• Faithfully copies coder_eval 0.11.5's _normalize_shell / _match_haystacks surface — correct approach given coder_eval isn't a test dependency.
• test_filters_criteria_match_the_replayed_templates (line 191) ties the test's CRITERIA templates to the actual shipped YAML, catching template drift.
• test_shipped_guard_never_stops_at_a_newline (line 177) checks both YAML files for substring presence of both rejected guard variants — clean regression gate.
• Controls E (chained &&) and F (stacked newlines) verify fix(traces): segment-scope list_* graders; stop gating on default sort order #2836's batched-call fix is preserved.
• Regression-pinning tests (lines 204, 209) lock in the failure modes of the old guard and the (?<!\\)\n variant, preventing either from quietly returning.

The control matrix covers all the important edge cases (correct two-call, merged single-command, break-between-flags, wrong offset, wrong subcommand, chained, stacked).

4. tests/README.md

Severity: OK

Two corrections at lines 441 and 448:

• "also matches a normalized haystack with newlines collapsed to spaces" → "also matches a shlex-normalized haystack" — fixes the false claim that made fix(traces): segment-scope list_* graders; stop gating on default sort order #2836's review look sound.
• Updated segment idiom example and added a clear "Do NOT put \n in that stop list" paragraph with the technical rationale (shlex behavior, both haystacks preserving the newline). Good guardrail for future task authors.

5. .github/workflows/test-helpers.yml

Severity: OK

• New command-pattern-guard job follows the same structure as sibling jobs (pinned action SHAs, Python 3.13).
• Correctly installs pyyaml alongside pytest (the test imports yaml).
• tests/tasks/uipath-platform/** added to trigger paths — correct, since the test reads YAML files from that directory and edits to those files should re-run the guard.

What's Missing

Nothing identified. The PR is well-scoped: it fixes exactly the regression, updates the documentation that led to the incorrect review, and adds a comprehensive regression test. The sibling trace tasks that don't use the segment guard idiom (e.g., traces_feedback_comment_file_smoke.yaml using unscoped [\s\S]* lookaheads) are a pre-existing pattern outside this PR's scope.

Area Ratings

Area	Status	Notes
Frontmatter	OK	Task YAML frontmatter unchanged and valid
E2E Tests	OK	Existing tasks updated; new regression test added with CI job
Skill Body	N/A	No skill files under skills/ modified
References & Assets	OK	tests/README.md corrected accurately
Repo Hygiene	OK	No secrets, no cross-skill deps, scoped changes, CODEOWNERS not needed (no new skill paths)

Issues for Manual Review

• The coder_eval _normalize_shell copy is pinned to v0.11.5. If coder_eval changes its haystack matching in a future version, this test could diverge. The comment at line 30 documents this — acceptable tradeoff since coder_eval isn't a test dependency.
• The final test-plan checkbox ("Next nightly Claude run scores above 0") is pending — worth confirming after merge.

Conclusion

Clean PR. The root-cause analysis is rigorous (shlex behavior with backslash continuations), the fix is minimal (remove \n from the stop list, use [\s\S] for explicitness), and the 7-control × 2-shape matrix is thorough enough to prevent reintroduction. All CI checks pass. No issues found — approve.