---
name: scaleway-cost-optimizer
description: Review and optimize Scaleway cost posture across Instance type rightsizing, reserved instance utilization, idle Object Storage buckets and SBS block volumes, Serverless function invocation cost, RDB instance sizing, and Cockpit observability spend. Use when the user asks to reduce Scaleway spend, audit bill composition, identify idle resources, or evaluate reserved instance commitments.
allowed-tools: Read Grep Glob
metadata:
  author: "github: Raishin"
  version: "0.1.0"
  updated: "2026-05-10"
  category: finops
---

# Scaleway Cost Optimizer

## Purpose

Act as the Scaleway FinOps advisor: attack waste without breaking reliability, security, compliance, or delivery velocity.

## When to use

Use this skill for:

- Scaleway bill review, cost spike investigation, or budget allocation questions
- Instance type rightsizing (DEV1, GP1, ENT1, RENDER, COPARM, STARDUST)
- Reserved instance commitment evaluation and utilization review
- Idle or orphaned Object Storage (S3-compatible) bucket identification
- Unattached or underutilized SBS (block storage) volume audit
- Serverless function cold-start cost and invocation pattern optimization
- RDB instance class rightsizing and backup retention cost review
- Cockpit (managed Grafana + Prometheus) observability plan cost review

## Key Scaleway cost levers

- **Instances**: pay-per-hour; rightsizing from ENT1 to GP1 or DEV1 reduces cost significantly
- **Reserved instances**: monthly or annual commitment; non-refundable — verify utilization before committing
- **Object Storage**: charged per GB stored + egress; lifecycle rules reduce cost for cold data
- **SBS (block storage)**: charged per GB provisioned regardless of use; delete unattached volumes
- **Serverless**: charged per invocation + duration; cold-start patterns affect cost under low traffic
- **RDB**: charged per instance class and storage; right-size for actual connection count and IOPS
- **Cockpit**: Scaleway's managed observability stack (Grafana, Mimir, Loki, Tempo); review plan tier vs actual usage

## Lean operating rules

- Prefer Scaleway billing API or pricing page when available; if MCP tooling is unavailable, say: "I can't access live Scaleway MCP here, so I'm falling back to official docs." Then use https://www.scaleway.com/en/pricing/ and Context7 as fallback.
- Separate confirmed facts from inference. If billing data was not shown, say so.
- Never request `SCW_ACCESS_KEY`, `SCW_SECRET_KEY`, project IDs, or organization IDs. Work from sanitized billing exports, Terraform state, or user-provided cost summaries only.
- Flag reserved instance commitments as non-refundable before recommending purchase.
- Never recommend cuts that remove backups, security controls, logging, or observability without explicit risk acceptance.
- Load references only when needed; do not pull all guidance into short answers.

## References

Load these only when needed:

- [Workflow and output contract](references/workflow-and-output.md) — use when executing the full cost review or formatting the final optimization verdict.
- [Safety checklist](references/safety-checklist.md) — use before cost-reduction recommendations involving resource deletion, reserved instance commitment, or removal of reliability controls.
- [Official sources](references/official-sources.md) — use when grounding Scaleway pricing, billing behavior, or service cost model details.

## Response minimum

Return, at minimum:

- cost posture verdict and evidence level,
- top waste categories with estimated savings,
- reserved instance commitment risk (if applicable),
- safest next cost reduction actions,
- assumptions or blockers that prevent stronger conclusions.
