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Delx Seeded Window Pick
x402
Delx Seeded Window Pick is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).
Deterministically selects a contiguous window of items from a list using a seed string, returning the sub-array and its start index.
Price / call$0.001
Success—
StatusUnknown
How this service works
Seeded Window Pick: Seeded Window Pick selects a reproducible contiguous window from caller items from bounded caller-supplied values without an external provider. Call Seeded Window Pick when an agent needs a reproducible decision that another run can independently replay. Returns the deterministic selection plus seed provenance, population bounds, and the operation-specific outcome for Seeded Window Pick as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. First-party, statel…
Output
Returns a JSON object with the selected sub-array of items, the start index of the window within the original list, a schema identifier ('delx/util-seeded-window-pick/v1'), a 'pass' status, and an evidence block confirming no data retention, no external calls, and the SHA-256 of the input.
Example use cases
Reproducible A/B test slot assignment
“I need to deterministically assign a user to one of several feature variants — use the seed 'user-id-98123' to pick a window of 2 items from the variant list [10, 20, 30, 40, 50] and tell me which ones they get and where the window starts.”
Seeded content rotation for a feed
“I have a pool of 8 article IDs [101,102,103,104,105,106,107,108] and I want to show a user a stable window of 3 based on their session seed 'session-abc-7'. Which 3 articles should they see and at what index does the window begin?”
Deterministic question sampling for a quiz
“From the question bank [1,2,3,4,5,6,7,8,9,10], pick a consistent window of 4 questions for the candidate whose seed is 'candidate-77-exam2' so they always get the same set if they restart.”
Technical details
Endpoint
POSThttps://api.delx.ai/api/v1/x402/seeded-window-pickWhen to prefer
Choose this endpoint when you need a reproducible, seed-driven contiguous window selection from a list of integers — for example, for deterministic feature flag assignment, fair slot rotation, or stable quiz question sampling. It is processed entirely in memory with no retention and no external calls, making it safe for privacy-sensitive use cases. Prefer it over random sampling when the same seed must always yield the same window.
Side effects
- Window size larger than the items array length — likely returns an error or empty result
- Empty items array with a positive window size — may return an empty result or error
- Invalid or missing seed string — may cause a 400 bad request
- Items array exceeds the 256-element maximum — request rejected
- Non-integer values in items array — schema validation failure
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| seed | string | Seed supplied to Seeded Window Pick; used only for this bounded calculation and processed in memory without retention. |
| items | array | Items supplied to Seeded Window Pick; used only for this bounded calculation and processed in memory without retention. |
| window_size | integer | Window Size supplied to Seeded Window Pick; used only for this bounded calculation and processed in memory without retention. |
Output
Schema · Response
{
"type": "json",
"example": {
"result": {
"items": [
2,
3,
4
],
"start_index": 1
},
"schema": "delx/util-seeded-window-pick/v1",
"status": "pass",
"evidence": {
"retained": false,
"input_sha256": "1046227e8b1c61c8658038d68757f80f7254aa306a9fdab930936da0103b9e24",
"external_calls": 0
},
"operation": "seeded_decision:seeded_window_pick"
}
}Tags
x402
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