Optimize vector index performance for latency, recall, and memory.
SkillScore91Maintained
Automatic
◆AI Engineer pack
Last verified 8/12/2026
What it changes
Passed 19 of 21 test cases with the skill, and 15 of 21 without it.
Without skill73%
With skill91%
Checks it passed that the model alone missed
Recommends a flat index (exact search) instead of approximate nearest neighbor search
Establishes a baseline performance benchmark using default index parameters before tuning
Advises against index parameter tuning until query metrics or ground truth validation sets are established
and 1 more in the full report
4 fixed16 passed either way2 still failing0 broke
Pass-rate lift
+18 pp
Tokens
+2%
Agent turns
0%
Response time
-11%
Model gemini-3.6-flashMeasured 8/12/2026v120 of 22 cases passed with skill · 21 comparable
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 3 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 3
Prompt
We want to optimize our vector index parameters for a newly ingested dataset of 500,000 document chunks, but we do not have any query logs, relevance labels, or ground truth nearest neighbors to compute recall. How should we perform the parameter sweep?
What was checked, without and with the skill
Checked
Without skill
With skill
Advises against index parameter tuning until query metrics or ground truth validation sets are established
Missed
Passed
case-02 · gemini-3.6-flash · 8/12/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md42 linessingle file
Vector Index Tuning
Guide to optimizing vector indexes for production performance.
Use this skill when
Tuning HNSW parameters
Implementing quantization
Optimizing memory usage
Reducing search latency
Balancing recall vs speed
Scaling to billions of vectors
Do not use this skill when
You only need exact search on small datasets (use a flat index)
You lack workload metrics or ground truth to validate recall
You need end-to-end retrieval system design beyond index tuning
Instructions
Gather workload targets (latency, recall, QPS), data size, and memory budget.
Choose an index type and establish a baseline with default parameters.
Benchmark parameter sweeps using real queries and track recall, latency, and memory.
Validate changes on a staging dataset before rolling out to production.
Refer to resources/implementation-playbook.md for detailed patterns, checklists, and templates.
Safety
Avoid reindexing in production without a rollback plan.
Validate changes under realistic load before applying globally.
Track recall regressions and revert if quality drops.
Resources
resources/implementation-playbook.md for detailed patterns, checklists, and templates.
Limitations
Use this skill only when the task clearly matches the scope described above.