Hmbown/CodeWhale · error · anyhow::Error

{name}.context_window must be greater than 0

Error message

{name}.context_window must be greater than 0

What it means

Provider context-window validation (crates/tui/src/config.rs:3605) rejects an explicit context_window = 0, both for builtin overrides and custom [providers.<name>] entries. Zero would make every context-budget calculation degenerate, so it fails config validation by name, e.g. providers.myhost.context_window.

Source

Thrown at crates/tui/src/config.rs:3605

            ("providers.sakana", &self.sakana),
            ("providers.opencode_go", &self.opencode_go),
            ("providers.opencode_zen", &self.opencode_zen),
            ("providers.meta", &self.meta),
            ("providers.xai", &self.xai),
        ];
        for (name, config) in builtins {
            validate_provider_context_window(name, config.context_window)?;
        }
        for (name, config) in &self.custom {
            validate_provider_context_window(&format!("providers.{name}"), config.context_window)?;
        }
        Ok(())
    }
}

fn validate_provider_context_window(name: &str, value: Option<u32>) -> Result<()> {
    if value == Some(0) {
        anyhow::bail!("{name}.context_window must be greater than 0");
    }
    Ok(())
}

#[derive(Debug, Clone, Deserialize, Default)]
struct ConfigFile {
    #[serde(flatten)]
    base: Config,
    profiles: Option<HashMap<String, Config>>,
}

#[derive(Debug, Clone, Deserialize, Default)]
struct RequirementsFile {
    #[serde(default)]
    allowed_approval_policies: Vec<String>,
    #[serde(default)]
    allowed_sandbox_modes: Vec<String>,
}

View on GitHub (pinned to 8880682c63)

Solutions

1. Set a positive token count matching the model (e.g. 128000)
2. Or delete the context_window key entirely to fall back to defaults
3. Re-run config load to confirm the validation passes

Example fix

# config.toml - before
[providers.myhost]
api_base = "http://localhost:8000/v1"
context_window = 0

# config.toml - after
[providers.myhost]
api_base = "http://localhost:8000/v1"
context_window = 128000

for (name, p) in &custom_providers {
    if p.context_window == Some(0) {
        return Err(anyhow!("{name}.context_window must be > 0"));
    }
}

fn valid_context_window(v: Option<u32>) -> bool { v != Some(0) }

// When generating provider config, omit the key rather than zeroing it
let toml = if cw > 0 { format!("context_window = {cw}\n") } else { String::new() };

When it happens

Trigger: A custom provider entry with context_window = 0 left as a placeholder; an override table where 0 was meant as 'use default'; YAML-to-TOML conversions producing zeros for empty values.

Common situations: Copy-pasted custom provider templates with placeholder zeros; scripts generating provider sections.

Related errors

• Invalid provider '{provider}': expected {}.
• Invalid default_text_model '{model}' for provider '{}': expe
• ${name} is required
• ${names.join(" or ")} is required
• ${name} is required

AI-assisted analysis of Hmbown/CodeWhale@8880682c63 (2026-08-16). Data as JSON: /api/errors/1b0fa5b9c075925e. Report an issue: GitHub.