# Principal Systems Engineer — Round 1 Review

**Branch:** `colonyos/when_you_output_followups_in_the_thread_on_slack_a938599349`
**Commit range:** 9 commits, +1,300 / -23 lines across 8 files
**Tests:** 131 pass (test_slack_formatting.py + test_sanitize.py)

## Checklist Assessment

### Completeness
- [x] **FR-1** Task completion messages include description — `phase_header` now includes sanitized, truncated task description (60-char limit with `...` ellipsis)
- [x] **FR-2** Task outline uses bullet formatting — `_format_task_outline_note()` switched from semicolons to `\n•` bullets with bold header, overflow at 6 tasks
- [x] **FR-3** Task result summary includes descriptions — `_format_task_list_with_descriptions()` renders cost/duration suffix, bullet format, overflow
- [x] **FR-4** Review round messages include finding summaries — `_extract_review_findings_summary()` with 3-tier fallback (FINDINGS → SYNTHESIS → first line)
- [x] **FR-5** All untrusted content double-sanitized — `sanitize_untrusted_content()` then `sanitize_for_slack()` at every ingress point
- [x] Zero new LLM calls — purely string extraction from existing artifacts
- [x] 3,000-char message cap enforced via `_truncate_slack_message()`

### Quality
- [x] 131 tests pass, covering formatting, sanitization, overflow, truncation, injection vectors
- [x] Named constants (`_SLACK_MAX_CHARS`, `_SLACK_MAX_SHOWN_TASKS`, etc.) extracted — no magic numbers
- [x] Follows existing project patterns (private function naming, PhaseResult artifacts, sanitize module)
- [x] No unnecessary dependencies added
- [x] No unrelated changes

### Safety
- [x] No secrets or credentials
- [x] Sanitization covers: mrkdwn metacharacters, @mention injection, `<url|text>` link injection, `<@U...>` user mentions, blockquote injection, bare links
- [x] Error handling: `try/except (ValueError, TypeError)` around cost/duration formatting; graceful fallback when `task_results` artifact missing

## Findings

### Non-Blocking

1. **[src/colonyos/sanitize.py] `_SLACK_BARE_LINK_RE` only matches `https?://`** — The `sanitize_for_slack()` function uses `_SLACK_LINK_INJECTION_RE` (which handles arbitrary URI schemes like `mailto:`, `slack://`) for `<scheme://url|text>` patterns, but falls back to `_SLACK_BARE_LINK_RE` for bare `<url>` patterns which only matches `http://` and `https://`. A bare `<mailto:user@corp.com>` or `<slack://open?team=T123>` without display text would not be stripped. Low risk — Slack auto-linkifies these, and the mrkdwn escaping pass will escape `<` if it survives the regex, but worth noting for defense-in-depth.

2. **[src/colonyos/orchestrator.py] FR-1 truncation at 60 chars vs PRD's 72 chars** — The PRD specifies task descriptions truncated to 72 chars in the `phase_header` call (FR-1), but the implementation truncates at 60 chars (`safe_desc[:60]` / `safe_desc[:57] + "..."`). The task outline and result formatters correctly use `_SLACK_TASK_DESC_MAX = 72`. This inconsistency is cosmetic — 60 chars is fine for a phase header where the description is appended to `Implement [1.0]` — but diverges from the spec.

3. **[src/colonyos/orchestrator.py] `_extract_review_findings_summary` — blank-line handling is permissive** — The parser continues collecting findings across blank lines, stopping only at a non-`-`-prefixed non-blank line. This means a review result with ad-hoc text between findings and synthesis would collect incorrectly. In practice, the review instruction template produces well-structured output, so this is academic. The test `test_blank_lines_between_findings` covers this exact behavior.

4. **[src/colonyos/orchestrator.py] No per-reviewer truncation in `_format_review_round_note`** — Each reviewer's findings are individually capped at 2 × 80 chars, but with many reviewers (e.g., 10 all requesting changes), the pre-truncation message could be long. The outer `_truncate_slack_message()` catches this, but it's a blunt instrument — it cuts at a newline, potentially dropping entire reviewer entries without indication of which reviewers were dropped. In the current ColonyOS pipeline, reviewer count is typically 4-5, so this is unlikely to matter.

5. **[tests/test_slack_formatting.py] `_extract_review_findings_summary` import guard** — The `try/except ImportError` guard around `_extract_review_findings_summary` is vestigial — it was needed during incremental development (task 4.0 hadn't landed yet) but now the function always exists. Minor dead code, but doesn't affect correctness.

## Reliability & Operability Assessment

**What happens when this fails at 3am?** The formatting functions are pure — no I/O, no network calls, no shared state. If a formatter raises an unexpected exception, the existing `try/except` in the calling code (`_run_pipeline`) would catch it. The truncation is defense-in-depth against Slack API rejections (messages exceeding limits). The fallback path when `task_results` is missing/unparseable produces a degraded-but-functional count-only summary.

**Race conditions?** None introduced. All new code is synchronous string processing on data already collected.

**Debugging from logs alone?** The sanitization module logs stripped URLs at DEBUG level (existing behavior). The new formatting functions don't add logging, which is appropriate — they're deterministic transformers. If a message looks wrong in Slack, you can reproduce it by feeding the same `task_results`/`PhaseResult` artifacts into the formatter in a REPL.

**Blast radius?** Minimal. Changes are confined to display-layer formatting. A bug would produce ugly Slack messages, not corrupt pipeline state or lose work.

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VERDICT: approve

FINDINGS:
- [src/colonyos/sanitize.py]: _SLACK_BARE_LINK_RE only matches http/https — bare mailto:/slack:// links without display text not stripped. Low risk.
- [src/colonyos/orchestrator.py]: FR-1 phase_header truncates descriptions at 60 chars, PRD specifies 72. Cosmetic divergence.
- [src/colonyos/orchestrator.py]: With many reviewers all requesting changes, _truncate_slack_message may drop entire reviewer entries without indicating which were dropped. Unlikely with typical 4-5 reviewer count.
- [tests/test_slack_formatting.py]: Vestigial try/except ImportError guard around _extract_review_findings_summary import.

SYNTHESIS:
This is a clean, well-scoped feature that does exactly what it says — threads existing data through to Slack formatting with proper sanitization. The architecture is correct: pure formatting functions, no new I/O, double-sanitization at every untrusted content ingress, deterministic truncation. The 3-tier fallback in finding extraction handles real-world LLM output variance without over-engineering. The 131 tests cover the important cases: overflow, truncation, injection vectors, fallback paths. The blast radius is minimal — worst case is ugly messages, not lost work. All four findings are non-blocking cosmetic items. Ship it.
