Define SLOs that mean something. Most "SLOs" in the wild are arbitrary numbers nobody believes — 99.9% on every endpoint, no SLI definition, no error budget policy. This skill enforces the Google SRE Workbook discipline.

What's inside

3 stdlib Python tools — SLO designer, error-budget calculator with multi-window burn-rate alerts, SLO reviewer
4 reference docs — principles, SLI design, error budget, composition
2 asset templates — SLO YAML, error budget policy
/slo-design slash command

Install

# Via Claude Code marketplace
/plugin install slo-architect

# Or clone the repo
git clone https://github.com/alirezarezvani/claude-skills.git
cd claude-skills/engineering/slo-architect

Quick start

SKILL=engineering/slo-architect/skills/slo-architect

# 1. Design an SLO
python "$SKILL/scripts/slo_designer.py" \
  --service checkout-svc --sli-type request-success-rate \
  --target 99.9 --window-days 28

# 2. Compute error budget + multi-window burn-rate alerts
python "$SKILL/scripts/error_budget_calculator.py" --target 99.9 --window-days 28

# 3. Review existing SLOs for common bugs
python "$SKILL/scripts/slo_review.py" --slo-doc docs/slos/

Key principles

An SLO is a promise about user experience — not a CPU graph
Pick the SLI from the user's perspective — request-success / latency / availability / freshness / correctness
Pick the target from data — measure 30 days, then floor it
Multi-window burn-rate alerts — single-window is either too noisy or too slow
Error budget without a policy is theater — every SLO ships with a policy

The 5 SLI types

User experience	SLI type
"Did the request succeed?"	request-success-rate
"Was the response fast?"	request-latency
"Was the service up?"	availability-time
"Is the data current?"	data-freshness
"Was the answer correct?"	correctness

Composition with the rest of the portfolio

Skill	Composition
`feature-flags-architect`	Rollout abort criteria reference SLO burn-rate thresholds
`chaos-engineering`	Blast-radius calculator takes monthly error budget as input
`kubernetes-operator`	Operator capability L4 requires SLOs + Prometheus rules

Skill structure

slo-architect/
├── README.md
├── .claude-plugin/plugin.json
└── skills/slo-architect/
    ├── SKILL.md
    ├── scripts/
    │   ├── slo_designer.py
    │   ├── error_budget_calculator.py
    │   └── slo_review.py
    ├── references/
    │   ├── slo_principles.md
    │   ├── sli_design.md
    │   ├── error_budget.md
    │   └── composition.md
    └── assets/
        ├── slo_template.yaml
        └── error_budget_policy.md

Verifiable success

A team using this skill should achieve:

100% of SLOs pass slo_review.py with 0 FAIL findings
Every SLO has a documented owner, error budget, burn-rate alerts, and policy
Burn-rate alerts fire ≤2 times/month per SLO that's hit
Mean time to detect SLO violation: <30 min
Quarterly SLO review actually happens

License

MIT — see repo root LICENSE.