Discover / math.openverbs.com

List expression variables

■ Challenge detected

Parse an expression and return the free variables it references, without evaluating it — so an agent can discover which inputs a formula needs before supplying values. A syntax error is a clean 400.

x402
Base
USDC

Listed price: $0.004
Challenge detected: 9 of the last 9 checks
Median response: 177 ms
Last checked: 16 Oct, 18:49 UTC
In our index since: 26 Sept 2026

Endpoint

curl -i https://math.openverbs.com/v1/variables
# 402 Payment Required: pay with an x402 client (USDC on Base),
# then send the same request again with the payment attached.

2 listed endpoints · on x402 Bazaar

Checks and payment terms on this page refer to the endpoint above. Other listed endpoints have not been checked individually.

Base URLhttps://math.openverbs.com/v1

POST/variables$0.004Parse an expression and return the free variables it references, without evaluating it — so an agent can discover which inputs a formula needs before supplying values. A syntax error is a clean 400.
POST/eval$0.004Evaluate a mathematical expression with optional named variables — arithmetic, comparison and logic operators plus functions like sqrt, abs, min, max, sin, cos, log, floor, round, etc. A syntax error, an undefined variable, or a non-finite result is a clean 400. The factorial operator is disabled for safety.

A dash means the listing gives no price or method. Copy buttons copy the full URL.

Showing 2 of 2 listed endpoints.

Agents can find it through the Superstables MCP server and JSON API: GET /api/v1/services/math.openverbs.com

Recent checks

2 Oct 2026One bar per check, showing up to 20 recent checks. Coloured bars show relative response time, with a minimum visible height; full-height grey bars mean no challenge was detected. “Challenge detected” means HTTP 402 or another detected payment-challenge signal.16 Oct 2026

All 9 checks

When (UTC)	Result	HTTP	Response
16 Oct, 18:49 UTC	Challenge detected	402	191ms
15 Oct, 11:37 UTC	Challenge detected	402	175ms
14 Oct, 00:19 UTC	Challenge detected	402	200ms
12 Oct, 00:34 UTC	Challenge detected	402	188ms
10 Oct, 10:04 UTC	Challenge detected	402	237ms
9 Oct, 03:33 UTC	Challenge detected	402	172ms
8 Oct, 00:44 UTC	Challenge detected	402	172ms
6 Oct, 21:30 UTC	Challenge detected	402	177ms
2 Oct, 17:03 UTC	Challenge detected	402	176ms

Questions

Did our last probe detect a payment challenge?

At our last probe on 16 Oct, 18:49 UTC, it returned HTTP 402 or another detected payment-challenge signal. This check did not test payment, delivery or compatibility with the Superstables client.

What price is recorded for List expression variables?

Its listed price is $0.004.

What payment terms does List expression variables advertise?

The listing advertises x402, Base and USDC. It names cdp as its facilitator. Check the seller's current payment challenge and authentication requirements before paying.

Where is List expression variables listed?

In x402 Bazaar. Superstables first indexed it on 26 Sept 2026.

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