arca-mcp AGENTS.md

arca-mcp AGENTS.md is an instructions file for Codex, OpenCode from ramide1/arca-mcp. It costs 510 tokens per session, scanned A, original, MIT.

Repository instructions for developing arca-mcp, a server that connects software to Argentina’s AFIP tax services.

In plain words
What is it for?
Installing and starting the server, checking its TypeScript code, configuring AFIP authentication, using test or production mode, and working with electronic-invoicing services.
Why use it?
They document the commands, certificates, environment settings, input format, and external requirements needed to run and maintain the server correctly.

Instructions file for CodexOpenCode

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.

agentmods
npx agentmods add instructions/ramide1/arca-mcp/agents-md
Clone the repo
git clone --depth 1 https://github.com/ramide1/arca-mcp

Made for: Codex, OpenCode.

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 arca-mcp AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/ramide1/arca-mcp/agents-md.svg)](https://agentmods.dev/instructions/ramide1/arca-mcp/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/ramide1/arca-mcp/agents-md"><img src="https://agentmods.dev/badge/instructions/ramide1/arca-mcp/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 510 This file is loaded in full into every session.
When invoked 510 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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 $0.00510 $0.00510
Opus 5 $0.00255 $0.00255
Sonnet 5 $0.00102 $0.00102
Haiku 4.5 $0.00051 $0.00051

Measured 3d ago against content hash ed8048a1d248, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

arca-mcp AGENTS.md scanned grade A with 0 findings 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 3d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

AGENTS.md · 36 lines

What it actually says

arca-mcp Agent Guidelines

Key Commands

  • **Start server: Install: bun install
  • Run: bun src/main.ts
  • Type check: bun tsc (no emission due to noEmit: true in tsconfig)
  • No test or lint scripts configured

Environment Variables

Required for AFIP authentication (WS-AAA):

  • ARCA_WSAA_CERT: Certificate file (default: ghf.crt)
  • ARCA_WSAA_PRIVATE_KEY: Private key file (default: ghf.key)
  • ARCA_WSAA_PASSWORD: Private key password (default: empty)
  • ARCA_TEST_MODE: Set to false for production; any other value (or unset) uses homologation
  • ARCA_FETCH_LIMIT: SOAP retry attempts (default: 3)

Certificate and key files are expected in the current directory (or currentDir tool parameter).

Important Notes

  • CUIT format: All tools require CUIT in XX-XXXXXXXX-X format (validated via Zod)
  • WSDL caching: WSDL files are downloaded to ./{service}_{env}.wsdl (e.g., wsfe_test.wsdl) and reused for 1 year
  • OpenSSL required: The signTra function uses openssl cms for signing; ensure OpenSSL is installed and in PATH
  • SOAP services: Communicates with AFIP's WS-FE (electronic invoicing) and WSAA (authentication) services
  • Temp files: Creates TRA_*.xml and TA_*.xml files in the directory specified by currentDir (default: ./)
  • TypeScript: Strict type checking enabled; moduleResolution: bundler (Bun-specific)
  • Project structure:
    • src/main.ts: MCP server entry point
    • src/tool.ts: MCP tool definitions (AFIP service wrappers)
    • src/arcaService.ts: SOAP client implementation
    • src/interface.ts: Unused (empty)

Development Notes

  • No test framework configured; manual testing via MCP tools recommended
  • No lint/formatter config in repo (though .gitignore references ESLint/Prettier)
  • Uses Bun's built-in test runner? Not configured
  • WSDL downloads occur on first use or when cached file >1 year old
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. 3d ago First seen · 36 lines · 510 tokens per session scan A ed8048a1d248

Subscribe to this mod's changes

arca-mcp AGENTS.md is an instructions file published in the GitHub repository ramide1/arca-mcp (0 stars, last pushed 1mo ago), licensed MIT. It adds 510 tokens to every session, about $0.0026 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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