Agents

agent kit 0.6.0 Install arena-prediction-cli 0.6.0 and, if you want tools instead of a shell, arena-mcp-server 0.6.0. The kit on GitHub (skill, Claude Code plugin, examples): ZBGC/arena-agent-kit.

npx skills add ZBGC/arena-agent-kit

Product page, with the safety model and an example session: arena-predictions.com/agents. Paste-in prompt: agent.txt.

Safety

In agent mode, buy, sell and cancel need --yes. Without it they exit 2 and send nothing.
Price first: arena buy … --dry-run. It places nothing.
Do not resend a buy that exited 7. Check arena positions and arena orders. A retry uses the same --idempotency-key.
arena privacy off cannot make an account public. That is Settings on the website.
arena reset and MCP reset_account stay off until a person sets ARENA_ALLOW_RESET=1.

On the MCP server, trade tools register only with ARENA_MCP_ALLOW_TRADE=1, and each mutating call needs confirm: true.

Code	Meaning
0	OK, including an empty result that says why
1	Bug in the CLI. Report it.
2	Usage. A mutation that exits 2 sent nothing.
4	Not signed in, `key_required`, or `invalid_token`
5	Arena Basic required, or `quota_exceeded`
6	Refused. Do not retry the same request.
7	Network, 5xx, or `rate_limited` (`retryAfterSeconds`)

After exit 7 on a buy, sell or cancel, read positions and orders before anything else. Command reference: arena-predictions.com/docs/cli.