nautechsystems/nautilus_trader · error · anyhow::Error

Tag slug '{slug}' not found

Error message

Tag slug '{slug}' not found

What it means

resolve_tag_slug fetches all Gamma tags via client.request_tags(), looks up the tag whose slug matches, and errors with "Tag slug '{slug}' not found" when no tag in the returned list has that slug. This happens before any numeric tag ID can be used in Gamma event queries.

Source

Thrown at crates/adapters/polymarket/src/providers.rs:1043

fn parse_gamma_filter_string(scope: &str, key: &str, value: &str) -> anyhow::Result<String> {
    if value.trim().is_empty() {
        anyhow::bail!("Gamma {scope} filter '{key}' cannot be empty")
    }
    Ok(value.to_string())
}

/// Resolves a tag slug to a tag ID by querying the Gamma tags endpoint.
pub async fn resolve_tag_slug(
    client: &PolymarketGammaHttpClient,
    slug: &str,
) -> anyhow::Result<u64> {
    let tags = client.request_tags().await?;
    let tag_id = tags
        .iter()
        .find(|t| t.slug.as_deref() == Some(slug))
        .map(|t| t.id.as_str())
        .ok_or_else(|| anyhow::anyhow!("Tag slug '{slug}' not found"))?;
    tag_id
        .parse::<u64>()
        .map_err(|e| anyhow::anyhow!("Tag slug '{slug}' returned invalid ID '{tag_id}': {e}"))
}

#[async_trait(?Send)]
impl InstrumentProvider for PolymarketInstrumentProvider {
    fn store(&self) -> &InstrumentStore {
        &self.store
    }

    fn store_mut(&mut self) -> &mut InstrumentStore {
        &mut self.store
    }

    async fn load_all(&mut self, filters: Option<&HashMap<String, String>>) -> anyhow::Result<()> {
        let instruments = self.fetch_bulk_instruments(filters).await?;
        self.replace_instruments(instruments);

View on GitHub (pinned to 18893faf8b)

Solutions

1. Verify the exact slug against Polymarket's Gamma tags endpoint (slugs are matched exactly via t.slug == Some(slug))
2. Refresh the tag list — request_tags() is fetched live each call, so a newly added slug works immediately
3. Update the config to use the numeric tag ID directly instead of slug resolution where possible
4. Check network/proxy responses; a truncated tag list can hide a valid slug

Example fix

// before
let tag_id = resolve_tag_slug(&client, "Politics").await?;
// after
let tag_id = resolve_tag_slug(&client, "politics").await?;

// Rust: verify slug exists against a cached tag list before querying
fn slug_known(tags: &[GammaTag], slug: &str) -> bool {
    tags.iter().any(|t| t.slug.as_deref() == Some(slug))
}

// Rust
match resolve_tag_slug(&client, slug).await {
    Ok(id) => id,
    Err(e) if e.to_string().contains("not found") => {
        eprintln!("unknown tag slug '{slug}'; check https://gamma-api.polymarket.com/tags");
        return Err(e);
    }
    Err(e) => return Err(e),
}

When it happens

Trigger: Calling resolve_tag_slug with a slug string that does not exist in Polymarket's Gamma tag list at request time (or an async task within any query path that resolves a tag filter).

Common situations: Typo in slug (case-sensitive match: 'Politics' vs 'politics'), slug renamed/retired by Polymarket, network returning a partial tag list, or stale config referencing an old slug.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

• Tag slug '{slug}' returned invalid ID '{tag_id}': {e}
• All {total_slugs} slug requests failed
• RTDS task owner was dropped
• params.validate_keyset().map_err(|e| anyhow::anyhow!(e))?;
• Gamma {scope} filter '{key}' must be an unsigned integer: {e

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/73086ae13edac00f. Report an issue: GitHub.