Kimi Formula web search exceeded the bounded tool-call loop

Error message

Kimi Formula web search exceeded the bounded tool-call loop

What it means

The Kimi Formula (K3) web-search flow is a bounded loop: rounds of function fibers are executed and results fed back until the model answers, capped by the shared MAX_NATIVE_SEARCH_TOOL_CALLS budget (8). If the loop runs out of budget while the model keeps requesting fibers, the client bails to prevent unbounded loops and runaway cost.

Solutions

Narrow or split the search query to reduce required rounds
Increase MAX_NATIVE_SEARCH_TOOL_CALLS if legitimately needed (watch cost/latency)
Check for a model-side loop (identical query repeatedly) and consider retrying the request
Fall back to the built-in native search path or a different model

Example fix

// before
bail!("Kimi Formula web search exceeded the bounded tool-call loop")
// after
bail!("Kimi Formula web search exceeded the bounded tool-call loop after {tool_calls_executed} calls; last query: {last_query}")

Defensive patterns

Strategy: fallback

Validate before calling

// estimate rounds and warn early
if expected_rounds * calls_per_round > MAX_NATIVE_SEARCH_TOOL_CALLS { warn!("likely to exceed search budget"); }

Try / catch

match provider.search_formula(req).await {
    Err(e) if e.to_string().contains("bounded tool-call loop") => {
        eprintln!("Formula search exceeded budget; splitting the query");
        split_and_search(req).await
    }
    other => other,
}

Prevention

Split research-style tasks into multiple bounded searches
Watch for the model re-issuing the same query (loop signature)
Tune MAX_NATIVE_SEARCH_TOOL_CALLS from observed round counts, not guesses

When it happens

Trigger: search_formula exhausts its loop iterations because the K3 model repeatedly requests web-search fibers and never returns a final answer within the 8-call budget (reserve_native_search_tool_calls rejecting further reservations throws first if the per-round additions exceed the cap).

Common situations: Broad queries requiring many search rounds; a K3 model looping on the same query; budget too small for research-style tasks.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

AI-assisted analysis of Hmbown/CodeWhale@73e0f67d83 (2026-09-22). Data as JSON: /api/errors/8ef38a67919cfd40. Report an issue: GitHub.

Appendix: source

Thrown at crates/tui/src/client/provider_native_search/kimi.rs:212

                .context("Kimi Formula web-search call omitted arguments")?;
            let _: Value = serde_json::from_str(arguments)
                .context("Kimi Formula web-search arguments were not valid JSON")?;
            let fiber = client
                .post_json(
                    &fiber_url,
                    &json!({ "name": name, "arguments": arguments }),
                    &[],
                )
                .await?;
            messages.push(json!({
                "role": "tool",
                "tool_call_id": id,
                "content": formula_fiber_result(&fiber)?,
            }));
        }
    }

    bail!("Kimi Formula web search exceeded the bounded tool-call loop")
}

fn reserve_native_search_tool_calls(executed: &mut usize, additional: usize) -> Result<()> {
    let total = executed
        .checked_add(additional)
        .context("Kimi native web search tool-call count overflowed")?;
    if total > MAX_NATIVE_SEARCH_TOOL_CALLS {
        bail!(
            "Kimi native web search exceeded the {MAX_NATIVE_SEARCH_TOOL_CALLS}-call safety limit"
        );
    }
    *executed = total;
    Ok(())
}

fn formula_web_search_tools(payload: &Value) -> Result<Value> {
    let tools = payload
        .get("tools")

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