Slo check

SLO Check

Turn raw event counts into a clear SLO scorecard with error-budget accounting.

Input

The user provides: $ARGUMENTS

This may be:

• empty — use the default SLO targets below over all available data
• targets like "completion=95 success=99 error=1" — override the defaults (percentages)
• a window like "last 7d" or "today" — restrict the measurement period

Default SLO targets: completion rate ≥ 95%, tool success rate ≥ 99%, error rate ≤ 1%.

Data Sources

Endpoint	Returns
GET /api/analytics	event_types (PreToolUse, PostToolUse, APIError counts), sessions_by_status, daily_events (365d), daily_sessions (365d) — the raw numerators/denominators for every SLI
GET /api/stats	total_sessions, total_events, events_today, sessions_by_status — fleet totals and recency
GET /api/events?session_id=X	Per-session stream — drill into the sessions that breach an SLO

Report Sections

1. Service Level Indicators (SLIs)

Compute each SLI from GET /api/analytics / GET /api/stats:

• Completion rate = completed sessions / total sessions (from sessions_by_status; count active/running as in-flight, exclude them from the denominator if still open).
• Tool success rate = PostToolUse / PreToolUse (capped at 100%).
• Error rate = APIError / total_events. Within a window, derive the numerators/denominators from daily_events / daily_sessions.

2. SLO Scorecard

For each SLI, compare to its target and mark MET ✅ or BREACHED ❌.

3. Error Budget

For each objective, report the error budget and how much remains:

• Budget = 1 − target (e.g., 1% for a 99% target).
• For "higher-is-better" SLOs (completion, success): remaining = (observed − target) / (1 − target).
• For "lower-is-better" SLOs (error rate): remaining = (target − observed) / target.
• A negative result means the budget is exhausted — report how far over (e.g., "2.7× over budget").

4. Breach Drill-Down

For any breached SLO, list the sessions contributing most to the breach (most failed tools or most APIErrors) via GET /api/events?session_id=X.

Output

• A Markdown scorecard table: SLI | observed | target | status | error budget remaining.
• Rates as percentages to 2 decimals; any currency in USD to 4 decimals.
• Cite exact counts and session_id values — never fabricate numerators or denominators.
• End with the SLO most at risk and the single action that would recover the most budget.
• Read-only: only report what the API returns. If curl cannot reach http://localhost:4820, tell the user to start the dashboard with npm start from the repo root.