Glean Common Errors

Overview

Glean provides enterprise search across connected data sources with AI-powered results. API integrations involve two distinct token types (indexing vs. client) and a custom datasource model for pushing content. Common errors stem from token type mismatches, permission misconfiguration that silently hides documents from search results, and bulk indexing failures caused by duplicate upload IDs or oversized documents. Stale results are a frequent complaint -- Glean indexes asynchronously, so newly pushed documents may take 1-5 minutes to appear in search. This reference covers authentication, indexing pipeline, and search-time issues.

Error Reference

| Code | Message | Cause | Fix | |------|---------|-------|-----| | 401 | Unauthorized | Invalid or expired API token | Regenerate at Admin > Settings > API Tokens | | 403 | Wrong token type | Using indexing token for search API | Indexing API needs indexing token; Client API needs client token with X-Glean-Auth-Type: BEARER | | 400 | uploadId already used | Duplicate bulk upload identifier | Generate a unique UUID per upload run | | 400 | document too large | Document body exceeds 100KB limit | Truncate or split content before indexing | | 400 | invalid datasource | Datasource not registered | Create datasource first via adddatasource endpoint | | 400 | missing required field | Document lacks id or title | Ensure every document has both id and title fields | | 403 | Permission denied | Document visibility restricted | Set allowAnonymousAccess: true or add user/group to permissions | | 429 | Rate limit exceeded | Too many API requests | Implement exponential backoff; batch indexing calls |

Error Handler

typescript
interface GleanError {
  code: number;
  message: string;
  category: "auth" | "rate_limit" | "indexing" | "permission";
}

function classifyGleanError(status: number, body: string): GleanError {
  if (status === 401) {
    return { code: 401, message: body, category: "auth" };
  }
  if (status === 429) {
    return { code: 429, message: "Rate limit exceeded", category: "rate_limit" };
  }
  if (status === 403 && body.includes("permission")) {
    return { code: 403, message: body, category: "permission" };
  }
  if (status === 400) {
    return { code: 400, message: body, category: "indexing" };
  }
  return { code: status, message: body, category: "auth" };
}

Debugging Guide

Authentication Errors

Glean uses two distinct token types. Indexing tokens authenticate bulk document uploads. Client tokens authenticate search queries and require the X-Glean-Auth-Type: BEARER header. Using the wrong token type returns 403, not 401 -- check the token type first.

Rate Limit Errors

Glean enforces per-token rate limits. Indexing operations should batch documents (up to 100 per request). Search queries are rate-limited per client token. Use Retry-After header when present and implement exponential backoff starting at 2 seconds.

Validation Errors

Bulk index uploads require a unique uploadId per run -- reusing an ID silently drops the upload. Documents must include both id and title fields. Content bodies over 100KB are rejected; truncate or split large documents. New datasources must be registered via adddatasource before any documents can be indexed against them. The datasource field in each document must exactly match the registered datasource name (case-sensitive).

Error Handling

| Scenario | Pattern | Recovery | |----------|---------|----------| | No search results after indexing | Processing delay (1-5 min) | Wait 5 minutes, then verify with direct document lookup | | Stale results returned | Index not refreshed | Trigger re-index; check datasource sync schedule | | Permission mismatch | User lacks document access | Add user/group to document permissions or enable anonymous access | | Bulk upload silently dropped | Duplicate uploadId | Always generate fresh UUID per upload run | | Token type confusion | 403 on search or index | Verify correct token type for the API being called |

Quick Diagnostic

bash
# Verify client token connectivity
curl -s -o /dev/null -w "%{http_code}" \
  -H "Authorization: Bearer $GLEAN_API_KEY" \
  -H "X-Glean-Auth-Type: BEARER" \
  https://your-domain.glean.com/api/v1/search

Resources

• Glean Developer Portal
• Indexing API Docs

Next Steps

See glean-debug-bundle.