Bug: search/list/read exec tool calls can complete with empty content when output fallback is skipped #290

Version

• @zed-industries/[email protected]
• Release: v0.14.0

Problem

• Some completed exec tool calls render without visible content.
• exec_command_output_delta resends entire accumulated output on every chunk, causing O(n²) memory growth and process crash on large command output #225 changed output handling to avoid resending accumulated output on every delta.
• Current code now accumulates output only from ExecCommandOutputDeltaEvent.
• ExecCommandEndEvent already carries aggregated_output and formatted_output.
• codex-acp discards both fields.
• If deltas are unavailable, skipped, or not accumulated, final visible content is empty.

Repro

1. Run Codex through codex-acp.
2. Trigger search/list/read commands that complete successfully.
3. Observe some completed tool calls have no visible content.

Expected

• Completed exec tool calls show available command output.
• If accumulated delta output is empty, use formatted_output or aggregated_output from ExecCommandEndEvent.

Actual

• Completed tool call can be status-only.
• ExecCommandEndEvent output fields are discarded.
• No fallback content is emitted.

Source refs

• exec_command_output_delta resends entire accumulated output on every chunk, causing O(n²) memory growth and process crash on large command output #225:
  exec_command_output_delta resends entire accumulated output on every chunk, causing O(n²) memory growth and process crash on large command output #225
• Output deltas are accumulated only in the non-terminal path:
  https://github.com/zed-industries/codex-acp/blob/v0.14.0/src/thread.rs#L2017-L2035
• ExecCommandEndEvent destructures and discards aggregated_output and formatted_output:
  https://github.com/zed-industries/codex-acp/blob/v0.14.0/src/thread.rs#L2040-L2059
• Final content uses only active_command.output:
  https://github.com/zed-industries/codex-acp/blob/v0.14.0/src/thread.rs#L2075-L2093
• Search commands are classified as ToolKind::Search, not terminal output:
  https://github.com/zed-industries/codex-acp/blob/v0.14.0/src/thread.rs#L2556-L2563