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.

Prerequisites

A redacted correlation ID, UTC timestamp, endpoint class, and HTTP status; omit headers, real queries, and indexed bodies.
A scoped read-only diagnostic credential, a named owner for any connector or ACL change, and a known-good synthetic probe.

Instructions

Classify the symptom by status code and operation before changing configuration.
Reproduce once with the synthetic probe and capture only status, latency band, and correlation ID.
Check token scope, rate-limit budget, request shape, connector freshness, and ACL watermark in that order.
Make one reversible fix at a time; access-scope changes require owner approval and allow/deny probes.
Escalate a redacted diagnostic bundle if the correlation class persists after rollback.

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

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

# 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

Output

Return error class, correlation ID, datasource, probe outcome, remediation attempted, and next owner. Never include credentials, query text, result snippets, or membership data.

Examples

status=429; source=sandbox-guides; correlation=req-opaque-17; action=backoff; retry_after=60s; synthetic_probe=recovered is sufficient for a safe rate-limit handoff.

Resources

Next Steps

See glean-debug-bundle.

glean-common-errors