# AgentShelf Character Diff

> AgentShelf Character Diff is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Computes a character-level diff between two input strings, returning the differences between them without any network calls.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/diff-chars?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentshelf-character-diff-addd3329
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_A3838eRC65UCVtQoE1kEE

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 agentshelf-character-diff-addd3329 -d '<json body>'
```

Example prompt: Can you give me a character-level diff between these two strings: 'Hello world!' and 'Hello Word!!'?

## When to prefer this

Use this endpoint when you need a precise, character-level diff between two strings and want a simple, low-cost ($0.001 USDC) computation. Prefer the free sandbox endpoint POST /v1/sandbox/diff-chars first for testing. Choose this over word-level or line-level diff services when character granularity matters.

## Known failure modes

- Input strings exceeding 100,000 characters each may be rejected
- Missing or malformed 'a' or 'b' fields return a validation error
- Payment of exactly $0.001 USDC required; incorrect payment may cause rejection

## How this service works

Call when an agent needs a chars diff of two strings. No network. Exact $0.001 USDC. Prefer unpaid POST /v1/sandbox/diff-chars first.

## Output

Returns a character-level diff showing exactly which characters were added, removed, or changed between the two input strings, computed locally without network access.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "a": {
   "type": "string",
   "examples": [
    "one two"
   ],
   "maxLength": 100000,
   "description": "Left-hand text."
  },
  "b": {
   "type": "string",
   "examples": [
    "one three"
   ],
   "maxLength": 100000,
   "description": "Right-hand text."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentshelf-character-diff-addd3329/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)