Hmbown/CodeWhale · error

context_window must be greater than 0

Error message

context_window must be greater than 0

What it means

Thrown by `parse_context_window` when the parsed `context_window` value is 0. The context window is a token budget and must be a positive count; a zero value would make the budget meaningless. Parsing itself must already have succeeded as a u32.

Solutions

1. Set `context_window` to the provider model's actual token limit (e.g. "128000").
2. Remove the `context_window` override entirely to fall back to the model's default.
3. Never use 0 to mean 'unlimited' — the field requires a positive integer.

Example fix

// before
context_window = "0"
// after
context_window = "200000"

fn valid_context_window(v: &str) -> bool {
    v.trim().parse::<u32>().map(|n| n > 0).unwrap_or(false)
}

match parse_context_window(value) {
    Err(e) if e.to_string().contains("greater than 0") => {
        // fall back to the model default instead of forcing 0
        config.providers.for_provider_mut(provider).context_window = None;
        Ok(())
    }
    other => other,
}

When it happens

Trigger: Setting a provider's `context_window` field (via `set_provider_config_value` or the ConfigToml setter) to "0" — the string parses fine as u32 but fails the >0 check.

Common situations: User typed `context_window = "0"` intending 'unlimited' or left a placeholder value; a template or script emitted 0 as a default.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

• Failed to update setting
• Failed to update setting: invalid
• agent profile provider cannot be empty
• agent profile provider must be a simple provider id
• api_key cannot be empty string

AI-assisted analysis of Hmbown/CodeWhale@73e0f67d83 (2026-09-22). Data as JSON: /api/errors/b9aae4b2312c3330. Report an issue: GitHub.

Appendix: source

Thrown at crates/config/src/lib.rs:1160

fn get_provider_config_display_value(
    config: &ProviderConfigToml,
    field: ProviderConfigField,
) -> Option<String> {
    match field {
        ProviderConfigField::ApiKey => config.api_key.as_deref().map(redact_secret),
        ProviderConfigField::HttpHeaders => {
            serialize_http_headers_for_display(&config.http_headers)
        }
        _ => get_provider_config_value(config, field),
    }
}

fn parse_context_window(value: &str) -> Result<u32> {
    let parsed = value.trim().parse::<u32>().with_context(|| {
        format!("invalid context_window '{value}': expected a positive token count")
    })?;
    if parsed == 0 {
        bail!("context_window must be greater than 0");
    }
    Ok(parsed)
}

fn set_provider_config_value(
    config: &mut ConfigToml,
    provider: ProviderKind,
    field: ProviderConfigField,
    value: &str,
) -> Result<()> {
    if provider == ProviderKind::Antigravity {
        bail!(LEGACY_ANTIGRAVITY_TOMBSTONE_MESSAGE);
    }
    match field {
        ProviderConfigField::Vendor => {
            if provider != ProviderKind::Openrouter {
                bail!("vendor is only supported by providers.openrouter");
            }

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