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.
npx skills add Captcha-Sonic/Agent-skills --skill captchasonic-balancegit clone --depth 1 https://github.com/Captcha-Sonic/Agent-skillsWrote 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.
[](https://agentmods.dev/skills/captcha-sonic/agent-skills/captchasonic-balance)<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.
<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>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.
| Model | Per session | Once 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 |
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"}' \ 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 statuserrorId—0means 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
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.
- 8d ago First seen · 69 lines · 34 tokens per session scan B 33567baca368
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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