zed-industries/zed · error · anyhow::Error

auto_compact threshold of 0 is not valid

Error message

auto_compact threshold of 0 is not valid

What it means

`auto_compact` threshold is parsed from a string in agent settings: a percent suffix (`"90%"`) becomes a `Percentage`, a positive integer becomes `TokensUsed`, a negative integer becomes `TokensRemaining` (unsigned absolute value), and exactly `0` — which fits neither direction — is rejected. The parse first strips whitespace (`trimmed`), so `" 0 "` and `"0"` both fail.

Solutions

  1. Set a valid threshold: `"90%"` (compact at 90% of context), `"100000"` (compact after 100k tokens used), or `"-20000"` (compact when 20k tokens remain).
  2. To effectively disable auto-compact, set a very high token count (e.g. `"1000000"`) rather than 0.
  3. Check for stray whitespace or a literal `0` mixed into a percent string when editing settings by hand.
  4. After editing, reload settings and confirm the agent panel no longer reports the parse error.

Example fix

// settings.json
// before
{ "agent": { "auto_compact": "0" } }
// after — compact at 90% of the context window
{ "agent": { "auto_compact": "90%" } }
Defensive patterns

Strategy: validation

Validate before calling

fn valid_auto_compact(raw: &str) -> bool {
    let t = raw.trim();
    if let Some(pct) = t.strip_suffix('%') { return pct.parse::<f64>().is_ok(); }
    match t.parse::<i64>() { Ok(n) => n != 0, Err(_) => false }
}

Try / catch

match AutoCompactThreshold::from_str_value(raw) {
    Err(e) if e.to_string().contains("threshold of 0") => {
        // suggest "90%" or a nonzero token count to the user
    }
    rest => rest,
}

Prevention

When it happens

Trigger: Setting `"agent.auto_compact": "0"` (or `"0%"`-adjacent forms that parse as the integer 0, e.g. `"00"`) in `settings.json`; passing `"0"` programmatically to the threshold parser.

Common situations: Users try to disable auto-compaction by setting the threshold to 0, or try to trigger compaction immediately; the setting expects either a percentage or a nonzero token count, and disabling is expressed differently (e.g. omitting the setting or a dedicated toggle).

Related errors

AI-assisted analysis of zed-industries/zed@916fc2b8cb (2026-08-20). Data as JSON: /api/errors/3918c7f50edf687d. Report an issue: GitHub.

Appendix: source

Thrown at crates/agent_settings/src/agent_settings.rs:204

            .parse()
            .with_context(|| format!("invalid auto_compact threshold percentage {raw:?}"))?;
        anyhow::ensure!(
            value > 0.0 && value <= 100.0,
            "auto_compact threshold percentage must be between 0% and 100%, got {raw:?}"
        );
        Ok(AutoCompactThreshold::Percentage(value / 100.0))
    } else {
        let tokens: i64 = trimmed.parse().with_context(|| {
            format!(
                "invalid auto_compact threshold {raw:?}; \
                 expected a percentage like \"90%\" or an integer number of tokens"
            )
        })?;
        match tokens.cmp(&0) {
            Greater => Ok(AutoCompactThreshold::TokensUsed(tokens as u64)),
            Less => Ok(AutoCompactThreshold::TokensRemaining(tokens.unsigned_abs())),
            Equal => {
                anyhow::bail!("auto_compact threshold of 0 is not valid")
            }
        }
    }
}

#[derive(Clone, Debug, RegisterSetting)]
pub struct AgentSettings {
    pub enabled: bool,
    pub button: bool,
    pub dock: DockPosition,
    pub flexible: bool,
    pub sidebar_side: SidebarDockPosition,
    pub threads_sidebar_default_width: Pixels,
    pub threads_sidebar_auto_open: bool,
    pub default_width: Pixels,
    pub default_height: Pixels,
    pub max_content_width: Option<Pixels>,
    pub default_model: Option<LanguageModelSelection>,

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