---
name: backend-development
description: "Use when implementing backend logic in C++ or Elixir/Phoenix."
---

# Backend Development

## When to invoke

Use when implementing backend logic in C++ or Elixir/Phoenix. Preserve the repository's established stack and conventions.

## Inputs and evidence

Inspect language/toolchain, resource ownership, service/contexts, concurrency boundaries, error contracts, and persistence. Identify installed versions, affected callers,
existing tests, and the user's requested behavior before editing.

## Workflow

1. Locate domain and I/O boundaries and preserve the project error and ownership model.
2. Implement the selected C++ resource-safe or Elixir context/supervision path with explicit expected failures.
3. Verify domain behavior, lifetime/concurrency failures, cancellation, and transport/database boundaries.

Load [implementation guidance](references/implementation.md) only for the selected
feature, API, or verification concern; follow its primary links for version details.

## Outputs and handoff

Report the changed behavior, affected files, checks and their actual outcomes,
and remaining limitations. Include relevant configuration or migration steps.

## Completion evidence

Verify the requested behavior at its public boundary, including a meaningful
failure case. Separate static review from executed tests and runtime acceptance.

## Must not

Do not change the stack, dependencies, or architecture merely to match examples.
Do not expose credentials or private data. External writes, deployments, paid
operations, and destructive changes require authority from the user's request.

---

Adapted from Mindrally/skills and modified by Andrew Cox (2026), under Apache-2.0. See [package notices](../../NOTICE.md).