# Delx EVM Log Topic Count Check

> Delx EVM Log Topic Count Check is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-13).

Validates that the number of EVM log topics in a list does not exceed a specified maximum, returning a pass/fail result with evidence metadata.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/evm-log-topic-count-check
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-evm-log-topic-count-check-c1ae8b96
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_x-4i19we85YY1sTYZyNvj

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability delx-evm-log-topic-count-check-c1ae8b96 -d '<json body>'
```

Example prompt: Before I submit this Ethereum transaction, check that my log topics list — ['0xaaa...', '0xbbb...', '0xccc...', '0xddd...'] — doesn't exceed the maximum of 4 topics allowed per EVM log entry.

## When to prefer this

Use this endpoint when building EVM transaction or log-filter pipelines where you need a lightweight, auditable preflight check to confirm topic arrays stay within protocol or application-defined ceilings before broadcasting or indexing. Prefer it over custom code when you need an evidence trail (SHA-256 hash, retained:false attestation) for compliance or debugging purposes.

## Known failure modes

- Topics array exceeds 256 items — request rejected
- Maximum not provided — validation may behave unexpectedly
- Malformed topic strings longer than 8192 characters — schema validation error
- Invalid JSON body — 400 error
- Network timeout — no result returned

## How this service works

EVM Log Topic Count Check: EVM Log Topic Count Check checks log topic count against an expected bound from bounded caller-supplied values without an external provider. Call EVM Log Topic Count Check before signing, submitting, replacing, or accepting an EVM/Base transaction assembled from caller-owned data. Returns normalized transaction evidence, calculated budget or shape findings, and a fail-closed preflight status for EVM Log Topic Count Check as versioned deterministic JSON. Price: $0.001…

## Output

Returns the original topics array, the counted number of topics, a boolean indicating whether the count is within the specified maximum, an overall pass/fail status, and evidence metadata including a SHA-256 hash of the input and confirmation that no data was retained or external calls made.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "topics": {
   "type": "array",
   "items": {
    "type": "string",
    "maxLength": 8192
   },
   "maxItems": 256,
   "description": "Topics supplied to EVM Log Topic Count Check; used only for this bounded calculation and processed in memory without retention."
  },
  "maximum": {
   "type": "integer",
   "description": "Maximum supplied to EVM Log Topic Count Check; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "topics": [
    "0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
   ],
   "topic_count": 1,
   "within_limit": true
  },
  "schema": "delx/util-evm-log-topic-count-check/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "94bb14a112913b6e521fe6f4d7a71088495e0a7177ac1eb18e1ff94e7d02627e",
   "external_calls": 0
  },
  "operation": "evm_preflight:evm_log_topic_count_check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-evm-log-topic-count-check-c1ae8b96/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)