Bug type

Behavior bug (incorrect output/state without crash)

Beta release blocker

No

Summary

OpenClaw-managed ACP sessions for Claude fail before producing output when OpenClaw applies generic runtime options as ACP session config options. Direct ACPX to Claude works on the same system, while the OpenClaw-managed ACP path fails with AcpRuntimeError: Internal error.

Steps to reproduce

1. Configure ACP with the Claude ACP agent available.
2. Verify direct ACPX can start Claude and complete a trivial prompt.
3. Start a Claude session through OpenClaw managed ACP, for example sessions_spawn with runtime="acp" and agentId="claude", using a trivial prompt such as "Reply exactly: CLAUDE_ACP_OK".
4. Observe that the managed ACP session fails before returning model output.
5. Separately, send ACP session/set_config_option calls for unsupported config IDs such as timeout, thinking, or approval_policy to the Claude ACP adapter; the adapter rejects them as unknown config options / internal errors.

Expected behavior

OpenClaw should only apply ACP session config options that the target adapter advertises/supports, or should ignore/degrade gracefully for unsupported runtime options. A trivial OpenClaw-managed Claude ACP session should complete when direct ACPX to Claude succeeds.

Actual behavior

The OpenClaw-managed Claude ACP session fails before output with AcpRuntimeError: Internal error. Manual ACP testing shows the Claude ACP adapter rejects unsupported config IDs such as timeout, thinking, and approval_policy; current Claude ACP config options include mode, model, and effort/thought-level, not those generic OpenClaw runtime keys.

OpenClaw version

2026.4.26

Operating system

Ubuntu 26.04 LTS

Install method

npm global install / OpenClaw Gateway service

Model

Claude Code via ACP; repro also uses trivial exact-response prompts rather than model-specific behavior

Provider / routing chain

OpenClaw managed ACP runtime -> ACPX backend -> Claude ACP adapter -> Claude Code

Additional provider/model setup details

Direct ACPX to Claude succeeds on the same machine/auth setup. Tested with ACPX 0.6.1 and Claude Code 2.1.119. Latest checked Claude ACP adapter package exposes mode/model/effort config options; unsupported generic runtime keys are rejected.

Logs, screenshots, and evidence

Sanitized evidence:
- Direct ACPX -> Claude: trivial prompt completed successfully.
- OpenClaw managed ACP -> Claude: trivial prompt failed before output with AcpRuntimeError: Internal error.
- Manual ACP config-option checks: session/set_config_option with configId=timeout returns an unknown config option / internal error from the Claude ACP adapter. Similar generic keys such as thinking and approval_policy are not advertised Claude ACP config options.
- Current Claude ACP config options observed from the adapter are mode, model, and effort (category: thought_level).

Impact and severity

Claude Code is usable through direct ACPX but not through OpenClaw-managed ACP sessions. This blocks OpenClaw from reliably controlling Claude Code through the intended ACP runtime path.

Additional information

Suggested fix: during ACP session setup, derive the supported config option IDs from the adapter session response and only call session/set_config_option for advertised options. Map OpenClaw runtime concepts to adapter-specific config IDs where appropriate (for example effort/thought-level), and do not send generic keys such as timeout unless the adapter explicitly supports them.