[raymondk]

With neither --amount nor --cycles, icp cycles buy said only that --amount was required, as if --cycles were not a way in; and a negative value of either was read by clap as a flag nobody passed (-5t → "unexpected argument"), with no word about the sign.

Now a clap ArgGroup names both flags as the one required argument, and both options take a leading - as part of their value and refuse it in words ("cannot be negative: give the cycles to receive, such as 5t"), exit status 2 for both.

Code is Josh's, verbatim from #824 (commit 18f7794, argument-parsing part only). cli.md regenerated (usage line). Unit test amount_or_cycles_is_required_and_neither_may_be_negative and the extended integration test cycles_buy_rejects_conflicting_arguments.

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Part of restacking #824 into small PRs, one fix each, stacked on main in this order: cycles-buy/01-json-implies-yes → 02-arg-group → 03-gateway → 04-qr-colours → 05-paste-flags → then the wait, its follow-up text and the --json fields. Each PR targets the one below it; after the one below merges, retarget to main.

🤖 Generated with Claude Code

https://claude.ai/code/session_01Twxau844tMTwyHpQJEbmBo

[Copilot]

🟢 Approval recommended

Static review found no blocking issues, and targeted tests cover the intended behavior; tests were not executed.

No open issues 🎉

What changed in this PR

Improves icp cycles buy argument validation so missing purchase options and negative values produce clear, consistent errors.

Changes:

• Requires exactly one of --amount or --cycles.
• Rejects negative values during argument parsing with exit status 2.
• Adds regression coverage and updates documentation.

File	Description
docs/​reference/​cli.md	Updates usage to show the required alternatives.
crates/​icp-cli/​tests/​cycles_tests.rs	Extends argument-validation integration coverage.
crates/​icp-cli/​src/​commands/​cycles/​buy.rs	Adds argument grouping, sign validation, and unit tests.
CHANGELOG.md	Records the improved validation behavior.

_{Review effort: Balanced}