cli-qa

name	cli-qa
description	This skill should be used when the user asks to "QA a CLI tool", "verify a command-line program", "check the binary's output", "validate exit codes", "compare against a golden file", or wants end-to-end behavioural verification of command-line tools. Drives a binary with representative inputs, captures stdout / stderr / exit code as separate evidence channels, asserts via golden-file comparison with volatile-field redaction.
argument-hint	[scope of the CLI change to verify]

cli-QA

Drive the binary, capture stdout / stderr / exit separately, compare against the spec or a golden fixture.

Scope: $ARGUMENTS

If no scope was provided, read the recent changeset to determine which subcommands, flags, or output formats changed.

Bundled Resources

• references/golden-files.md — golden-file redaction (timestamps, PIDs, paths, widths, ANSI) and regenerate-on-purpose idiom. Load when the spec asserts byte-equality against a fixture.

Workflow

1. Read the changeset — git diff, git log — and identify the surface that changed: subcommand, flags, input parsing, output formatting, error reporting, exit-code semantics.
2. Build the binary in the worktree (GOWORK=off go build ./... for Go, project's build for others).
3. For each spec asserting CLI behaviour, drive the binary with a representative input.
4. Capture stdout, stderr, and exit code to three separate files. Never 2>&1 for the Oracle's transcript.
5. Compare the captures against the spec — equality, regex, golden-file with redaction.
6. Persist the transcript under .agent-history/oracle/<card-id>/<timestamp>/.

Driving the binary

TXN=.agent-history/oracle/$CARD_ID/$(date +%Y%m%dT%H%M%S)
mkdir -p "$TXN"

# Three channels, three files; preserve exit code
./bin/mytool subcommand --flag value \
  > "$TXN/stdout.txt" \
  2> "$TXN/stderr.txt"
echo "$?" > "$TXN/exit.txt"

echo $? captures the exit before anything else clobbers it. Pipelines clobber $? unless set -o pipefail.

Exit code conventions

126, 127, 128+N are POSIX-defined. 0, 1, 2 are program-defined and mean different things in different tools (git uses 1 for merge conflict; grep uses 1 for "no match"). Record the exit code as a fact; interpret only when the program documents its codes.

Code	Defined by	What it tells the Oracle
0	program	exit was graceful — the program decided everything succeeded
1, 2, 3, …	program	program-specific; check the program's docs/man page before interpreting
126	shell	command was found but not executable — a setup defect, not behaviour under test
127	shell	command was not found — the binary was not built; halt the QA
128 + N	shell	the program was killed by signal N (e.g., 130 = 128 + SIGINT, 137 = 128 + SIGKILL)

If the spec says "shall exit non-zero on bad input" without naming a code, mark could-not-determine and surface to the planner.

Pipeline gotchas

2>&1 collapses stderr into stdout — after that, "what went to stderr" is unanswerable. For multi-stage pipelines, set -euo pipefail makes any-stage failures propagate; without it, only the last stage's exit is consulted.

Environment that warps output

CLIs check more than isatty(1). Fix env-var levers for reproducibility:

Variable	Effect when unset / default	What to set for deterministic capture
TERM	colour, cursor codes vary	TERM=dumb for plainest output
NO_COLOR	many tools respect this	NO_COLOR=1 to disable colour even on TTYs
CI	many tools change output for CI	CI= (unset) or CI=1 per intent
LC_ALL / LANG	number / date format vary	LC_ALL=C
TZ	local-time output drifts	TZ=UTC
PAGER	tools like git log paginate	PAGER=cat to disable
COLUMNS	line-wrapping width	COLUMNS=80 for stable wraps

env -i HOME=$HOME PATH=$PATH TERM=dumb LC_ALL=C TZ=UTC ./bin/mytool ... is the heavy form when the spec asserts byte-exact output.

TTY-vs-pipe divergence

Many CLIs check isatty(1) and change output: colours, progress bars, pagination. The Oracle's redirected captures are pipes, so they record the non-TTY path. To assert TTY-only behaviour, force a PTY with script:

• script merges stdout and stderr under the PTY — separate channels are not recoverable. Pick TTY mode or separate channels.
• PTY transcripts carry \r, backspace, and ANSI control bytes; goldens need normalisation (tr -d '\r', ANSI strip).
• Flag spelling differs by platform:

if [[ "$OSTYPE" == darwin* ]]; then
  script -q /dev/null ./bin/mytool subcommand > "$TXN/transcript.txt"
else
  script -q -c './bin/mytool subcommand' /dev/null > "$TXN/transcript.txt"
fi
echo "$?" > "$TXN/exit.txt"

Signal-handling assertions

When the spec asserts shutdown behaviour ("shall exit cleanly on SIGINT"), drive the signal explicitly:

./bin/mytool serve >"$TXN/stdout.txt" 2>"$TXN/stderr.txt" &
PID=$!

# Poll for readiness — sleep is flaky for slow-starting binaries
for i in $(seq 1 60); do
  if grep -q 'listening' "$TXN/stderr.txt" 2>/dev/null; then break; fi
  sleep 0.1
done

kill -INT "$PID"
wait "$PID"; CODE=$?
echo "$CODE" > "$TXN/exit.txt"

If the binary handles SIGINT and exits with its own code, wait returns that code. If it doesn't and the kernel kills it, wait returns 130 (= 128 + SIGINT). The spec must say which case ("shall exit 0 on SIGINT" or "shall exit 130 uncaught") for the verdict to be unambiguous.

Golden-file comparison

For large or structurally complex output, compare against a fixture. Redaction (replacing volatiles with stable placeholders) is what makes golden files non-flaky. See references/golden-files.md.

# Quick recipe: redact obvious volatiles, then diff
sed -E '
  s/[0-9]{4}-[0-9]{2}-[0-9]{2}T[0-9:.+-]+/[TIMESTAMP]/g;
  s/(pid )[0-9]+/\1[PID]/g;
  s/\/tmp\/[A-Za-z0-9._-]+/[TMPPATH]/g;
' "$TXN/stdout.txt" > "$TXN/stdout.redacted.txt"

diff -u testdata/expected.txt "$TXN/stdout.redacted.txt" > "$TXN/diff.txt" || true

Evidence capture

Save artefacts under .agent-history/oracle/<card-id>/<timestamp>/:

• command.txt — the exact command line invoked, one line
• stdin.txt — input fed to the program, if any
• stdout.txt — raw stdout
• stdout.redacted.txt — stdout after volatile-field redaction (when comparing to a golden)
• stderr.txt — raw stderr
• exit.txt — single line: the exit code as a number
• diff.txt — output of diff -u golden observed, when applicable
• verdict.md — APPROVE / REJECT / ESCALATE with the spec table filled in

Side-effect assertions

When the spec asserts effects beyond stdout/stderr/exit, delegate:

• Database → db-state-qa (snapshot before/after, structural diff).
• Log content → log-tail-qa (bounded wait for pattern).
• File-system → find + stat.

Link the side-effect transcript from verdict.md.

Rules

• Three channels, three files. Never 2>&1 in the capture. Stderr carries information the spec may assert.
• Capture exit code immediately. echo $? on the next line. Pipelines and chained commands clobber it.
• Build the binary the Oracle exercises. GOWORK=off for Go in worktrees. A stale binary makes the verdict meaningless.
• Force a PTY when the spec asserts TTY-mode output. script -q on macOS, script -q -c on Linux. Capture both paths when both matter.
• Reproduce signal behaviour explicitly. Send the signal; wait; capture the code. Implicit shutdowns (SIGTERM at end of pipeline) are different from asserted SIGINT handling.
• Redact before diff. Timestamps, PIDs, temp paths, terminal widths, ANSI escapes. The redaction list belongs in references/golden-files.md.
• Regenerate goldens deliberately. A golden updated to match observed output is no longer a spec — it is a record. The Oracle does not regenerate; it reports mismatch and lets the worker decide.

Report Format

## CLI QA Report

**Scope**: <which subcommands / flags verified>
**Verdict**: APPROVE | REJECT | ESCALATE

### Build
- [PASS/FAIL] `<build command>` — <notes>

### Channels
| Trial | stdout | stderr | exit |
|---|---|---|---|
| 1 | <one-line summary or "see file"> | <same> | <code> |

### Specifications Verified
| Spec # | Assertion | Verified by | Verdict |
|--------|-----------|-------------|---------|
| 1 | (paste from bl show) | (file path / diff) | satisfied / unsatisfied / could-not-determine |

### Findings
1. <description with reproduction command and evidence path>

### Transcript
Path: `.agent-history/oracle/<card-id>/<timestamp>/`
Contents: <brief listing>