Cli Development

• Write primary result data to stdout.
• Write diagnostics, warnings, and human-oriented guidance to stderr.
• In machine mode (--json), print a complete structured success or error object to stdout.
• Document that automation should capture both stdout and stderr for full logs.

Help and Error Pattern

Use this pattern for each subcommand:

1. One-line purpose.
2. Usage line.
3. Required arguments.
4. Optional flags.
5. Examples, including one failure-recovery example.

When returning an error, format output in this order:

1. Error summary.
2. Known state.
3. Recovery options.
4. Exact next command.
5. Relevant subcommand help hint.

Output Templates

Success with next step:

Created release r123.
Next: mycli release publish r123

Success without next step:

Published release r123.
No further action required.

Failure with recovery:

Error: failed to publish release r123 (artifact missing).
Known state: release exists, build step did not produce dist/app.tar.gz.
Try: mycli release build r123
Then: mycli release publish r123
Help: mycli help release publish

Implementation Checklist

• Define root command and subcommand boundaries.
• Write subcommand help before command logic.
• Implement parser and validate required arguments.
• Implement success and failure output contracts.
• Verify stream contract: parseable payloads on stdout, diagnostics on stderr.
• Add tests for success, parser errors, and runtime failures.
• Verify each failure path includes state and next steps.