captchasonic-balance

captchasonic-balance is a skill for Claude Code from Captcha-Sonic/Agent-skills. It costs 34 tokens per session (578 once invoked), scanned B, original, MIT.

A guide for checking the remaining credits and connection status of a CaptchaSonic account through its MCP server. MCP is a way for an AI agent to use an external service through defined tools.

In plain words
What is it for?
It is for retrieving the account balance, interpreting the service response, and diagnosing missing or invalid API-key errors.
Why use it?
It shows whether the configured API key works and whether the account has enough credit for CAPTCHA-solving requests.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: positional $N argument.

Part of the captchasonic plugin — 4 skills, 1 MCP server shipped together

Good fit It is for retrieving the account balance, interpreting the service response, and diagnosing missing or invalid API-key errors.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/captcha-sonic/agent-skills/captchasonic-balance
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add Captcha-Sonic/Agent-skills --skill captchasonic-balance
Clone the repo
git clone --depth 1 https://github.com/Captcha-Sonic/Agent-skills

Made for: Claude Code.

Or install captchasonic, the plugin that ships this one along with the rest of its 4 skills, 1 MCP server.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for captchasonic-balance

README.md
[![agentmods](https://agentmods.dev/badge/skills/captcha-sonic/agent-skills/captchasonic-balance/github.svg)](https://agentmods.dev/skills/captcha-sonic/agent-skills/captchasonic-balance)
Your own site
<a href="https://agentmods.dev/skills/captcha-sonic/agent-skills/captchasonic-balance"><img src="https://agentmods.dev/badge/skills/captcha-sonic/agent-skills/captchasonic-balance/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for captchasonic-balance

Your own site · 80×15
<a href="https://agentmods.dev/skills/captcha-sonic/agent-skills/captchasonic-balance"><img src="https://agentmods.dev/badge/skills/captcha-sonic/agent-skills/captchasonic-balance.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 34 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 578 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00034 $0.00578
Opus 5 $0.00017 $0.00289
Sonnet 5 $0.00007 $0.00116
Haiku 4.5 $0.00003 $0.00058

Measured 8d ago against content hash 33567baca368, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade B, and why

captchasonic-balance scanned grade B with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Sends data to an external URLmediumData exfiltration

A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.

grpcurl -d '{"apiKey":"sonic_xxxx"}' \
skills/captchasonic-balance/SKILL.md · 69 lines

What it actually says

Check CaptchaSonic Balance

Use the CaptchaSonic MCP get_balance tool to check your account credits.

Prerequisites

The CaptchaSonic MCP server must be connected with a valid SONIC_API_KEY. If not set up, use the captchasonic-setup skill first.

Step 1: Call the MCP Tool

Use the get_balance MCP tool (no arguments needed — the API key is set via environment variable):

Tool: get_balance
Arguments: {}

Step 2: Interpret the Result

The tool returns:

  • balance — your remaining credits in USD (e.g., $12.5400)
  • status — account status
  • errorId0 means success

Step 3: Report to the User

Present the balance clearly:

  • If balance is healthy: "Your CaptchaSonic balance is $12.54 USD."
  • If balance is low (under $1.00): "⚠️ Your balance is $0.32 USD — consider topping up at captchasonic.com."
  • If balance is zero: "❌ Your balance is $0.00 — add credits at captchasonic.com to continue solving captchas."

Error Handling

Error Meaning Fix
"SONIC_API_KEY is not set" MCP server doesn't have the API key Re-add the MCP server with --env SONIC_API_KEY=sonic_xxxx
errorId: 1 Invalid API key Check your key at dashboard.captchasonic.com
Connection error MCP server not running Run npx -y @captchasonic/mcp-server or use the setup skill

Fallback: Python SDK

If the MCP server is not available:

pip install captchasonic
from captchasonic import SonicClient
import os

client = SonicClient(api_key=os.environ.get("SONIC_API_KEY", "sonic_xxxx"))
balance = client.get_balance()
print(f"Balance: ${balance:.4f} USD")
client.close()

Fallback: grpcurl

grpcurl -d '{"apiKey":"sonic_xxxx"}' \
  api.captchasonic.com:443 captchasonic.v1.SonicService/GetBalance
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 69 lines · 34 tokens per session scan B 33567baca368

Subscribe to this mod's changes

captchasonic-balance is a skill published in the GitHub repository Captcha-Sonic/Agent-skills (1 stars, last pushed 3mo ago), licensed MIT. It adds 34 tokens to every session and 578 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it B with 1 finding (sends data to an external url). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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