Hmbown/CodeWhale · error · anyhow::Error

Calling agent not found

Error message

Calling agent not found

What it means

Authority checks for subagent coordination require the calling agent's identity. Internal headless parents can own a worker record without a paired SubAgent projection, and when even the worker record lookup fails the check fails closed with this error because the caller's identity cannot be established.

Solutions

1. Re-open or re-derive the subagent session so caller records are rebuilt from the authoritative state
2. Check the subagent state root for a deleted/corrupt worker record and restore or re-spawn the parent
3. Retry after the current operation finishes — the caller may have been a transient headless parent

Example fix

// before
let caller_id = self.worker_record_by_ref(caller).map(|(id,_)| id).ok_or_else(|| anyhow!("Calling agent not found"))?;
// after (caller side)
if !self.has_agent(caller) { return Ok(Status::caller_gone); } // handle missing caller before invoking the control tool

fn caller_is_known(state: &SubAgentState, caller: &str) -> bool {
    state.worker_records.iter().any(|r| r.ref_name == caller) || state.agents.iter().any(|a| a.id == caller)
}

fn has_worker_record(state: &SubAgentState, caller: &str) -> bool {
    state.worker_records.iter().any(|r| r.ref_name == caller)
}

match ensure_caller_authority(state, caller, target) {
    Err(e) if e.to_string() == "Calling agent not found" => {
        // caller record vanished; rebuild state from disk or abort the coordination op gracefully
        rebuild_state_and_retry_or_abort()
    }
    Err(e) => return Err(e),
    Ok(()) => proceed(),
}

When it happens

Trigger: A coordination tool call (control/send/interrupt) where `caller` resolves neither to a continuation target SubAgent nor to a worker record — e.g. an unknown or already-removed caller ref passed by the engine or a stale record after cleanup.

Common situations: A caller agent being reaped mid-operation; a corrupted or manually edited subagent state directory dropping the worker record; engine passing an obsolete caller ref after session restart.

Understand the failure class

Background: "Not found" and "does not exist" errors: why "Task not found", "No such folder", and "Can't find" fire when a lookup comes back empty — this error's family across 14 libraries.

Related errors

• Agent continuation target is no longer retained
• Agent continuation target is outside the active session
• Agent not found
• Agent session not found
• Agent session name ' ' is ambiguous; use an agent_id

AI-assisted analysis of Hmbown/CodeWhale@73e0f67d83 (2026-09-22). Data as JSON: /api/errors/dfd9e54d9784bf15. Report an issue: GitHub.

Appendix: source

Thrown at crates/tui/src/tools/subagent/mod.rs:7560

        agent_ref: &str,
        caller_agent_id: Option<&str>,
        action: &str,
    ) -> Result<String> {
        let agent_id = self.resolve_agent_ref(agent_ref)?;
        let Some(caller) = caller_agent_id
            .map(str::trim)
            .filter(|caller| !caller.is_empty() && *caller != "root")
        else {
            return Ok(agent_id);
        };
        let caller_identity = if self.agents.contains_key(caller) {
            self.continuation_target(caller)?
        } else {
            // Internal headless parents can own a worker record without a
            // paired SubAgent projection. A missing caller still fails closed.
            self.worker_record_by_ref(caller)
                .map(|(id, _)| id)
                .ok_or_else(|| anyhow!("Calling agent not found"))?
        };
        if caller_identity == self.continuation_target(&agent_id)? {
            return Err(anyhow!(
                "Refusing {action} on self (agent_id '{agent_id}'); child coordination authority is limited to strict descendants."
            ));
        }

        let mut cursor = agent_id.clone();
        let mut visited = std::collections::HashSet::new();
        while visited.insert(cursor.clone()) {
            let Some((_, record)) = self.worker_record_by_ref(&cursor) else {
                break;
            };
            let Some(parent_ref) = record
                .parent_run_id
                .as_deref()
                .or(record.spec.parent_run_id.as_deref())
            else {

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