A command that adds one MCP server to the project's .mcp.json configuration file. MCP servers connect a coding agent to additional tools or services.

For connecting a named service, previewing its configuration, testing the connection, and saving it for the next Claude Code startup.

It avoids manually editing configuration and checks for duplicate servers. It can show the proposed settings, flag required credentials, and report whether a connection test succeeded.

add-mcp — Command for coding agents by ShipWithAI: A command that adds one MCP server to the…

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 commands/shipwithai/shipwithai-plugins/add-mcp

Clone the repo

git clone --depth 1 https://github.com/ShipWithAI/shipwithai-plugins

Or install shipwithai-starter, the plugin that ships this one along with the rest of its 13 skills, 4 commands, 1 agent.

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.

README.md

[![agentmods](https://agentmods.dev/badge/commands/shipwithai/shipwithai-plugins/add-mcp.svg)](https://agentmods.dev/commands/shipwithai/shipwithai-plugins/add-mcp)

Your own site

<a href="https://agentmods.dev/commands/shipwithai/shipwithai-plugins/add-mcp"><img src="https://agentmods.dev/badge/commands/shipwithai/shipwithai-plugins/add-mcp.svg" alt="Measured on agentmods" height="20"></a>

Per session 43 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 334 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.

Model	Per session	Once invoked
Fable 5	$0.00043	$0.00334
Opus 5	$0.00022	$0.00167
Sonnet 5	$0.00009	$0.00067
Haiku 4.5	$0.00004	$0.00033

Measured 5d ago against content hash 1468eb690121, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

add-mcp 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.

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.

plugins/starter/commands/add-mcp.md · 42 lines

What it actually says

/add-mcp

Add a single MCP server to .mcp.json. Stateless — no init context required.

Steps

If user provides a service name → look up in the plugin's mcp-registry.json (located at skills/setup-mcp/mcp-registry.json in the plugin directory).
- Found: show preset config, confirm.
- Not found: "Paste the MCP URL and a short description."

Show config preview before writing:

{
  "mcpServers": {
    "[name]": {
      "url": "...",
      "description": "..."
    }
  }
}

If authRequired is true in the registry entry: surface auth requirement before writing. Ask: "This server requires [authNote]. Do you have credentials ready?"
Attempt test connection → report ✓ tested / ⚪ configured-not-verified / ✗ not-found. Never report ✓ without actually testing. MCP servers load at next Claude Code startup.
Confirm → append to .mcp.json. Check for duplicate id before writing — skip if already present.
Update **Last updated:** date in the Harness config section of CLAUDE.md if the file exists.

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.

5d ago First seen · 42 lines · 43 tokens per session scan A 1468eb690121

Subscribe to this mod's changes

add-mcp is a command published in the GitHub repository ShipWithAI/shipwithai-plugins (10 stars, last pushed 23d ago), licensed MIT. It adds 43 tokens to every session and 334 once invoked, about $0.0002 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.

ai-coding claude-code claude-code-plugin developer-tools shipwithai

add-mcp

Getting it into your agent

Wrote this? Show the measurements

What it costs to keep this loaded

Grade A, and why

Nothing flagged

What it actually says

/add-mcp

Steps

What this file has done since we first saw it

Other commands, from other repositories

debug

whats-next

review

explore

specmanager-build

review-skills