Function evaluate_codex_subagent_start

src/hooks/codex.rs:214–268

Pure decision logic for Codex `SubagentStart` events.

(event_json: &str)

/// Pure decision logic for Codex `SubagentStart` events.
pub fn evaluate_codex_subagent_start(event_json: &str) -> Option<String> {
    let parsed: Value = serde_json::from_str(event_json).ok()?;
    let agent_type = parsed
        .get("agent_type")
        .or_else(|| parsed.get("subagent_type"))
        .and_then(Value::as_str)
        .unwrap_or_default();
    let task = parsed
        .get("prompt")
        .or_else(|| parsed.get("task"))
        .or_else(|| parsed.get("description"))
        .and_then(Value::as_str)
        .unwrap_or_default();

    let hint = decide_hint(&ToolHintInput {
        agent: HintAgent::Codex,
        session_id: event_session_id(&parsed),
        tool_name: Some("SubagentStart".to_string()),
        command: None,
        prompt: (!task.is_empty()).then(|| task.to_string()),
        subagent_type: (!agent_type.is_empty()).then(|| agent_type.to_string()),
        file_path: None,
        hints_enabled: true,
    });
    let is_explore = agent_type.eq_ignore_ascii_case("explore");
    let is_research = is_explore || is_code_research_prompt(task);
    let needs_context = codex_subagent_needs_context(&parsed);
    if is_research || needs_context {
        let dedupe_hint = ToolHint {
            category: if is_research {
                HintCategory::ExploreSubagent
            } else {
                HintCategory::SubagentStartContext
            },
            message: "For Codex subagents, add compact TraceDecay context before isolated work."
                .to_string(),
            context: CODEX_SUBAGENT_START_CONTEXT.to_string(),
            nonblocking: true,
        };
        let root = codex_project_root_from_event(event_json);
        let hint_id = mint_hint_id();
        record_hint_analytics(
            root.as_deref(),
            "hint_candidate",
            HintAgent::Codex,
            event_session_id(&parsed).as_deref(),
            &hint_id,
            &dedupe_hint,
        );
        let _ = deduped_codex_hint(event_json, &parsed, &hint_id, dedupe_hint)?;
        let context = codex_subagent_start_context(hint, needs_context);
        return Some(codex_additional_context_json("SubagentStart", &context));
    }
    None
}

/// Records a Codex `SubagentStart` and returns the session-local count.
pub fn record_codex_subagent_start(event_json: &str) -> Option<u64> {