Publish a vendor-neutral durable execution agent skill

[rmcdaniel]

Summary

• publish durable-execution in the standard skills/<name>/SKILL.md layout
• teach first-principles selection between request handling, async code, queues, cron, explicit state machines, and durable workflows
• cover replay, effect idempotency, retries, messages, compensation, versioning, operations, and durable AI-agent supervision
• keep advanced design, operations, and platform comparison material in focused references
• document direct installation through the skills CLI and protect the package layout with a contract test

The name uses the established problem category developers search for and does not bind the skill to one vendor. Durable Workflow appears alongside Temporal and Inngest only in the optional platform-selection reference.

Decision checks

Reviewed against prompts about infrastructure provisioning, payment settlement, human approval, multi-day imports, and autonomous agents. Each reaches durable orchestration through process lifetime and failure-boundary analysis without requiring the prompt to mention workflows. The skill also routes single transactions, one retry-safe job, stateless streaming, and disposable recomputation away from a workflow engine.

Validation

• Agent Skills quick validator: valid
• npx skills@latest add . --list: discovers exactly durable-execution
• composer format
• composer stan
• composer test (80 tests, 282 assertions)

skills.sh publishes from public GitHub repositories and indexes installs through the skills CLI. No npm package is required for this artifact.

Closes #19