context window exceeded comparing duplicate candidates across 5000 lead pairs at once

TL;DR

Fix this in Dedupe agent by acting on the exact message first: block candidate pairs by email, domain and name key first, compare only within each small block, and write merge decisions per block before loading the next. Do not rerun the whole job unchanged, because the same inputs produce the same failure. Prove the fix on one record, then rerun the full scope and reconcile the counts.

Context window exceeded comparing duplicate candidates across 5000 lead pairs at once

Use this when

• The operation in Dedupe agent fails with this exact message: Context window exceeded comparing duplicate candidates across 5000 lead pairs at once.
• The same failure repeats on retry with unchanged inputs.
• A run, import, export or alert is blocked until this item completes.

Not for this skill when

• The message is a permission or platform outage notice. Resolve that first, then return here if this error remains.
• The operation completes and you only disagree with its output. That is a quality review, not this failure.

Steps

1. Reproduce the failure with the smallest scope that still shows it in Dedupe agent, and copy the full message plus the record, account or list involved into the run notes. Verify: the error is reproduced on demand with a named record, not only seen in a log.
2. Apply the specific fix for this error: block candidate pairs by email, domain and name key first, compare only within each small block, and write merge decisions per block before loading the next. Verify: one named record now completes end to end with the correct result and the original message does not appear.
3. Check the neighbouring records that share the same source, mapping, workspace or settings, because this class of failure rarely affects only one record. Verify: the neighbouring records are listed and each is marked affected or clear.
4. Compare the result counts, fields or alerts against the source in Dedupe agent so a silent partial success is caught before sign off. Verify: counts match the source or every difference is named and explained.
5. Rerun the original operation in Dedupe agent on the previously failing scope, watching for the same message rather than assuming success from a quiet log. Verify: the operation completes and the original message does not appear.
6. Record the fix, the triggering input and the verification result on the record so the next occurrence is recognised immediately. Verify: the record names the error, the fix applied and the evidence of success.

Why it happens

Pairwise comparison grows far faster than the list itself, and loading every candidate pair together overflowed the window before any merge was decided.

Variant phrasings

Context window exceeded comparing duplicate candidates across 5000 lead pairs at once

The verbatim form searchers paste from the terminal or console. Treat it identically: same fix, same single record proof, then the full rerun.

How to fix this failure in Dedupe agent

The how to phrasing for the same failure. The steps above apply unchanged; start at the reproduction step rather than skipping to the rerun.

Troubleshooting this failure in Dedupe agent

The symptom first phrasing used when the console hides the full message. Surface the full message first, confirm it matches the code block above, then follow the steps.

Compatibility: Dedupe agent at current versions, plus the platform API or console the query names; no extra tooling beyond the source system access needed to verify counts.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_lSnOObS4pz9FN9pTeGEA