# Session Findings: 2026-03-28

## 1. Session Summary

**Work done**: Reviewed shiftstack adoption CI pipeline (MR !2964), pushed
code fixes (shiftstack-qa PS10, hypervisor tuning, secure.yaml permissions),
triggered full 7-stage pipeline on tp!2134, diagnosed the resulting failure
(run-shiftstack-after FAILURE, image-registry timeout).

**Zuul tools used**: 3 distinct tools, 7 total calls
- `get_change_status` (1 call) - pipeline/buildset status
- `diagnose_build` (1 call) - failure analysis
- `get_build_log` (4 calls) - log retrieval attempts
- `browse_build_logs` (1 call) - directory listing

**Overall friction**: Medium - `diagnose_build` worked excellently and
provided the key failure data in one call. But all 4 `get_build_log` calls
failed to produce useful output because the logs were gzipped.

## 2. Findings

### F1: `get_build_log` cannot read `.txt.gz` files (grep returns 0 matches, summary returns binary)

**Tool**: `get_build_log`
**Attempted**: Read `job-output.txt.gz` with grep patterns and summary mode
**Parameters used**:
```
uuid: b1c6451b8ba0473fa9b8d5c1d8e773dc
tenant: components-integration
log_name: job-output.txt.gz
grep: "Check.*Available|IMAGE_REGISTRY|TIMEOUT|fatal|..."
context: 2
```

**What happened**:
1. First call with `log_name: "job-output.txt"` → "Log file not found"
   (file was `.txt.gz`, not `.txt`)
2. Second call with `log_name: "job-output.txt.gz"` + grep → 0 matches
   (grep ran against compressed bytes, not text)
3. Third call with different grep pattern → 0 matches (same issue)
4. Fourth call with `mode: "summary"` → returned binary garbage in `tail`
   field (raw gzip bytes decoded as UTF-8 replacement chars)

**Severity**: P1 (significant gap) - `get_build_log` is the primary log
investigation tool. When logs are gzipped (which is common for completed
builds), it's completely non-functional. The user must fall back to
`diagnose_build` (which handles gzip internally) or use Bash/WebFetch.

**Suggested fix**: `get_build_log` should detect `.gz` extension (or gzip
magic bytes `\x1f\x8b`) and decompress before grep/summary/range operations.
The `get_build_failures` tool already handles this correctly (manual gzip
decompression per MEMORY.md: "detects raw gzip via magic bytes when server
omits Content-Encoding"). Apply the same pattern to `get_build_log`.

**Workaround used**: Relied on `diagnose_build` output which had the inner
playbook recap and failure details. No Bash workaround needed this time,
but only because `diagnose_build` happened to have enough context.

---

### F2: `get_build_log` doesn't auto-resolve `.txt` → `.txt.gz`

**Tool**: `get_build_log`
**Attempted**: `log_name: "job-output.txt"` (the intuitive name)
**What happened**: "Log file not found" - user had to call `browse_build_logs`
to discover the actual filename was `job-output.txt.gz`.

**Severity**: P2 (improvement) - minor friction, easy to work around with
`browse_build_logs`, but happens often since completed builds always have
gzipped logs.

**Suggested fix**: When `log_name` is not found, automatically try
`{log_name}.gz` before returning an error. Or always try both.

---

### F3: `browse_build_logs` required a separate call to discover log filenames

**Tool**: `browse_build_logs`
**Attempted**: List available log files after `get_build_log` failed
**What happened**: Worked correctly, returned directory listing showing
`job-output.txt.gz`. But this was a wasted round-trip.

**Severity**: P3 (polish) - `get_build_log` error message could include
available files: "Log file not found. Available: job-output.txt.gz,
logs/, zuul-info/"

**Suggested fix**: Include `available_files` in the error response of
`get_build_log` when the requested file is not found.

## 3. Missing Tools

None identified this session. The tool coverage was sufficient for the
babysit workflow. `get_change_status` + `diagnose_build` covered 95% of
the need.

## 4. What Worked Well

### `get_change_status` - excellent
Called with `change=2134, tenant=components-integration`. Returned full
buildset with all 7 builds, results, durations, and metadata in one call.
No follow-up needed. The `not_in_pipeline` + `latest_buildset` fallback
behavior worked perfectly for a completed build.

### `diagnose_build` - excellent
Called with build UUID. Returned structured failure data including:
- `failed_tasks` with task name, host, msg, rc, cmd
- `inner_recap` (nested ansible PLAY RECAP parsed out)
- `inner_failures` (nested fatal blocks extracted)
- `classification: REAL_FAILURE` with confidence and reason
- `invocation` with chdir (replay-relevant)
- Full stdout (148806 chars with smart truncation)

This single call provided everything needed to understand the failure.
The inner playbook parsing (`inner_recap`, `inner_failures`) was
particularly valuable - it extracted the nested ansible output from
the wrapper playbook's stdout.

### `browse_build_logs` - worked as expected
Simple directory listing, returned correct file list. No issues.
