Add database-migration-service-expertise skill for DMS operational re…

[abhit-cloud]

Description

Adds the database-migration-service-expertise skill (v1.0.0): AWS Database Migration Service domain expertise for AWS DevOps Agent, covering operational reviews, active troubleshooting, migration cutover guidance, and cost optimization.

Skill capabilities (all via AWS APIs — read-only):

• Operational Review — automated 5-category health scoring (Instance Health, Task Health, Endpoint Security, Performance, Cost Efficiency — 100 points) with per-finding severity and deduction rules, producing a shareable Markdown report artifact
• Troubleshooting — classifies task failures into 8 diagnostic categories (Connectivity, Resource Exhaustion, Performance/Latency, Data Mismatch, Table-Level Failure, Auth/Permissions, SSL/TLS, Silent Failure) with engine-specific log filter patterns and targeted CLI commands
• Migration Cutover — step-by-step runbook with pre-cutover checklist, CDC drain verification (CDCLatencySource/Target/IncomingChanges = 0 sustained), execution steps, rollback procedure, and post-cutover cleanup
• Version Management — cross-references engine versions against known bugs, EOL timelines, and feature availability matrices (3.4.6 through 3.6.1)
• Cost Optimization — detects idle instances, over-provisioned compute, unjustified Multi-AZ, and evaluates DMS Serverless suitability

What's included:

• skills/database-migration-service-expertise/ — SKILL.md, 3 reference files (best practices, validation checklist, version reference — 75 KB), evals (with committed Agent Skill Eval results)

Type of change

• New skill
• New custom agent
• Update to an existing skill or agent
• Documentation or infrastructure change

Testing

Agent Skill Eval (results committed under skills/database-migration-service-expertise/evals/):

• audit: 100/100, Grade A — 0 criticals, 0 warnings, 0 infos, passed
• functional: 100% with-skill vs 53% without-skill assertion pass rate (+47%), classified PARETO_BETTER (quality up, 46% fewer tokens), passed
• trigger: 100% trigger precision and 100% no-trigger precision (6 queries), passed
• unified report: 0.95, Grade A, "passed": true

Manual DevOps Agent testing (live Agent Space with DMS resources):

• Skill uploaded and activates consistently for DMS review/troubleshooting/cutover prompts without explicit skill invocation
• Tested 5+ realistic prompts across Chat tasks and Evaluation agent types
• Reasoning trace confirms skill steps followed (version check → data collection → analysis → report)
• Repeated tests show consistent activation and output quality

License confirmation

• By submitting this pull request, I confirm that my contribution is made under the terms of the Apache License 2.0.