Add output format option to suppress file READ operations while showing tool executions

[hayatosc]

Problem

I'm exploring acpx as a bridge for agent-to-agent communication
(e.g., Codex → acpx claude → claude review agent). Claude Code's claude -p
takes too long to return its first output, causing Codex
to treat the subprocess as unresponsive and repeatedly re-spawn it.
acpx's streaming output avoids this timeout issue, but file READ
operations return full file contents, which floods the calling
agent's context window.

The existing --format options don't cover this:

• text / json: include full READ content
• quiet: strips tool execution results entirely

Proposal

Add a way to suppress READ file contents while preserving other
tool execution results. Possible approaches:

• A new flag like --suppress-reads (composable with any format)
• A filter option on --format json to exclude specific event types
• A new format value like --format tools

This would make acpx more practical for agent-to-agent pipelines
where tool results matter but raw file contents are noise.

[yubingjiaocn]

Related use case: OpenClaw agent orchestrating acpx as a sub-agent via exec.

When running acpx --approve-all --max-turns 30 claude -s my-session "task" in a non-TTY pipe (e.g., spawned by another agent process), stdout is fully buffered by Node.js. The parent process sees zero output until acpx exits, making it impossible to monitor progress mid-run.

Workaround: running with pty: true forces line buffering and makes output visible in real-time. But this shouldn't require a PTY.

A --line-buffer / --unbuffered flag (or auto-detecting pipe mode and flushing after each event) would make acpx much more practical for agent-to-agent pipelines. This is closely related to the original ask here — both are about making acpx output consumable by non-human callers.

Environment: acpx 0.3.1, Node v24.14.0, Linux x64, invoked via OpenClaw exec.

[hayatosc]

this was added at #193 .
thanks @osolmaz !