mcp-echo

mcp-echo is a skill for Claude Code, Codex from runxhq/runx. It costs 17 tokens per session (34 once invoked), scanned A, original, Apache-2.0.

A skill that echoes a message through a local MCP server fixture. MCP is a way for an agent to use external tools.

In plain words
What is it for?
Use it to test local MCP communication and message handling.
Why use it?
It checks message exchange with a local server without relying on a remote service.

Skill for Claude CodeCodex

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 skills/runxhq/runx/mcp-echo
Any agent
npx skills add runxhq/runx --skill mcp-echo
Clone the repo
git clone --depth 1 https://github.com/runxhq/runx

Made for: Claude Code, Codex.

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 mcp-echo

README.md
[![agentmods](https://agentmods.dev/badge/skills/runxhq/runx/mcp-echo.svg)](https://agentmods.dev/skills/runxhq/runx/mcp-echo)
Your own site
<a href="https://agentmods.dev/skills/runxhq/runx/mcp-echo"><img src="https://agentmods.dev/badge/skills/runxhq/runx/mcp-echo.svg" alt="Measured on agentmods" height="20"></a>
Per session 17 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 34 The whole file, excluding the scripts and references it only reads on demand.
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 $0.00017 $0.00034
Opus 5 $0.00009 $0.00017
Sonnet 5 $0.00003 $0.00007
Haiku 4.5 $0.00002 $0.00003

Measured 5d ago against content hash 87c28fa64291, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

mcp-echo 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 5d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (stdio-server.mjs), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

fixtures/skills/mcp-echo/SKILL.md · 7 lines

What it actually says

Echo the provided message through a local MCP server fixture.

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 5d ago First seen · 7 lines · 17 tokens per session scan A 87c28fa64291

Subscribe to this mod's changes

mcp-echo is a skill published in the GitHub repository runxhq/runx (85 stars, last pushed yesterday), licensed Apache-2.0. It adds 17 tokens to every session and 34 once invoked, about $0.0001 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 2026-08-30.