Kimi harness launches `kimi --acp` (unknown option) and all Kimi agents fail to start

[alexwbend]

Summary
The built-in Kimi runtime invokes the Kimi Code CLI as kimi --acp, but the current Kimi Code CLI expects the subcommand kimi acp (no leading dashes). Every Kimi-harness agent crashes on launch with "unknown option '--acp'", and buzz-acp reports "all N agents failed to start — cannot continue".

Environment

• Buzz hosted relay (communities.buzz.xyz), desktop app, macOS
• Kimi Code CLI at ~/.kimi-code/bin/kimi (MoonshotAI/kimi-code)
• Built-in "Kimi" harness (id kimi-code); Arguments field = --acp

Steps to reproduce

1. Install Kimi Code CLI and log in (kimi, then /login).
2. Create an agent using the Kimi harness.
3. Start the agent.

Expected
buzz-acp launches Kimi in ACP mode via kimi acp; the agent initializes.

Actual
buzz-acp launches kimi --acp; Kimi exits and every instance fails:

agent_cmd=/Users/.../.kimi-code/bin/kimi --acp ...
error: unknown option '--acp'
ERROR buzz_acp: agent initialize failed: Agent process exited unexpectedly agent=0
Error: all N agents failed to start — cannot continue

Workaround
Point the Kimi harness Command at a shim that ignores the flag and runs the subcommand:

#!/usr/bin/env bash
exec "$HOME/.kimi-code/bin/kimi" acp

Suggested fix
The Kimi harness should invoke kimi acp (subcommand), not kimi --acp. Ref: Kimi Code docs — the kimi acp subcommand.

[iroiro147]

Root-caused and a fix is up in #4113.

Root cause. The Kimi preset on current main already ships the correct args: ["acp"] (spawned as kimi acp), but --acp persists in earlier-release harness definitions and in the instance-level Arguments field you saw. normalize_agent_args trimmed and filtered those args but passed a literal --acp straight through to the spawned command, and the modern Kimi Code CLI exits on the unknown option — so every Kimi agent died at launch with "agent process exited unexpectedly".

Fix. normalize_agent_args now canonicalizes a stray --acp / -acp flag form (case-insensitive) to the bare acp subcommand for all subcommand-style harnesses (kimi, omp, opencode, devin, cursor-agent, ...). Flag-style harnesses (codex-acp, claude-*, buzz-agent) are unaffected — their existing strip-to-empty rule still applies — and non-acp args pass through untouched. Line-level regression test covers the bare command, path-form commands (~/.kimi-code/bin/kimi), case-insensitivity, and multi-arg preservation.

Verified: cargo test --lib discovery (245 pass), cargo test --lib normalize (26 pass), cargo test --lib readiness (56 pass), pnpm typecheck clean.