Capture new Claude Code hook fields (effort, duration_ms, is_interrupt) - #200

What was missing

Claude Code hooks now send more input fields; the same set showed up in claude-agent-sdk 0.2.166 (braintrustdata/braintrust-sdk-python#973). The Claude Code translator reads payload fields directly instead of going through an allowlist, so last_assistant_message, error, and prompt_id were already being used. Three fields were still dropped:

The fix

Effort → turn metadata. effort is decoded in HookContext and tracked in observe_session_details together with permission_mode. Claude Code doesn't send effort on UserPromptSubmit; it shows up on later hooks (Stop, PreToolUse, PostToolUse). So reading it only when a turn opens isn't enough. Each turn tracks the level it has recorded, and when a different level arrives it is merged into the active turn:

UserPromptSubmit                   ──►  Turn 1 opens (effort unknown)
PreToolUse {effort:{level:"high"}} ──►  merge Turn 1  metadata.effort = "high"
Stop                               ──►  Turn 1 closes
/effort max
UserPromptSubmit                   ──►  Turn 2 opens  metadata.effort = "high" (carried)
Stop {effort:{level:"max"}}        ──►  merge Turn 2  metadata.effort = "max"

fn record_turn_effort(&mut self, ops: &mut Vec<SpanOp>) {
    let Some(turn) = self.turn.as_mut() else { return };
    if self.effort.is_none() || turn.effort == self.effort {
        return;
    }
    turn.effort = self.effort.clone();
    ops.push(SpanOp::Merge(SpanRow {
        span_id: turn.id.clone(),
        metadata: Some(json!({ "effort": turn.effort })),
        // ...
    }));
}

Tool timing / interrupts → tool metadata. finish_tool reads duration_ms once. That one value sets both native_duration_ms (the key the Cursor translator already uses) and the fallback start time, so the span timing and the metadata can't disagree:

let duration = event.payload.get("duration_ms").and_then(Value::as_i64);
if let Some(duration) = duration {
    metadata["native_duration_ms"] = json!(duration);
}
if let Some(interrupted) = event.payload.get("is_interrupt").and_then(Value::as_bool) {
    metadata["is_interrupt"] = json!(interrupted);
}
// ...
start_ms: Some(event.ts_ms.saturating_sub(duration.unwrap_or(0))),

Span timing doesn't change when PreToolUse exists: the span still runs from PreToolUse to PostToolUse.

prompt_id comment. The old comment said native hooks never send prompt_id. They now send it after the first user input, though older Claude Code versions leave it out. The matching code already handled both cases, so only the comment changed.

Test cleanup

The Claude translator tests went from 33 to 29 by merging overlapping cases: the three root-output tests, the two SubagentStart-validation tests, and the success and failure tool-outcome tests. Hand-built Envelope literals were replaced with the existing claude_event helper.

🤖 Generated with Claude Code