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mcp-dart-server

mcp-dart-server is a skill for Claude Code, Codex from leehack/mcp_dart. It costs 68 tokens per session (4,011 once invoked), scanned A, original, MIT.

A Dart guide for building a Model Context Protocol (MCP) server, a program that exposes tools, data resources, and reusable prompts to other programs. It covers project structure, server wiring, responses, errors, progress, transports, and tests.

In plain words
What is it for?
Use it to create or extend a Dart MCP server, register tools and resources, add prompts, run it over local process input/output or another transport, and test it with an in-process client.
Why use it?
It keeps protocol-specific code separate from application logic and provides a consistent layout for adding server features. It also helps make the server work with current and older MCP clients.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

not rated 116repo 3d ago A scan 68 tokens original MIT

Good fit Use it to create or extend a Dart MCP server, register tools and resources, add prompts, run it over local process input/output or another transport, and test it with an in-process client.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/leehack/mcp_dart/mcp-dart-server
View source ↗ leehack/mcp_dart
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 leehack/mcp_dart --skill mcp-dart-server
Clone the repo
git clone --depth 1 https://github.com/leehack/mcp_dart

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-dart-server

README.md
[![agentmods](https://agentmods.dev/badge/skills/leehack/mcp_dart/mcp-dart-server/github.svg)](https://agentmods.dev/skills/leehack/mcp_dart/mcp-dart-server)
Your own site
<a href="https://agentmods.dev/skills/leehack/mcp_dart/mcp-dart-server"><img src="https://agentmods.dev/badge/skills/leehack/mcp_dart/mcp-dart-server/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 mcp-dart-server

Your own site · 80×15
<a href="https://agentmods.dev/skills/leehack/mcp_dart/mcp-dart-server"><img src="https://agentmods.dev/badge/skills/leehack/mcp_dart/mcp-dart-server.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 68 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,011 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00068 $0.04011
Opus 5.5 $0.00027 $0.01604
Sonnet 5.5 $0.00014 $0.00802
Haiku 4.5 $0.00007 $0.00401

Measured 1mo ago against content hash e3e9dc23d497, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mcp-dart-server 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 1mo 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.

skills/mcp-dart-server/SKILL.md · 489 lines

How it starts

The opening of the file, as written. The whole thing — 489 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Building an MCP server with mcp_dart

McpServer exposes tools, resources and prompts to MCP clients. By default it speaks MCP 2026-07-28 and falls back to initialization-era versions (MCP 2025-11-25 and earlier) for legacy clients. Import everything from package:mcp_dart/mcp_dart.dart.

Project structure

Keep MCP wiring thin and separate from the application's logic. This is the layout that mcp_dart create generates; use it for hand-written servers too:

my_server/
  bin/server.dart               # Reads config, builds shared services, picks the transport.
  lib/mcp/mcp.dart              # createMcpServer(services): the only server factory.
  lib/mcp/tools/base_tool.dart  # BaseTool + registerBaseTool extension.
  lib/mcp/tools/*_tool.dart     # One class per tool; dependencies via the constructor.
  lib/mcp/resources/            # Resources and resource templates.
  lib/mcp/prompts/              # Prompts.
  lib/src/                      # Domain services and models; no mcp_dart imports.
  test/                         # In-process client/server tests.
  • If lib/mcp/tools/base_tool.dart already exists, the project came from mcp_dart create. Follow it: add a BaseTool subclass and list it in createAllTools(), and use BaseResource/BasePrompt the same way. Do not add inline registerTool calls beside that pattern.
  • To start a new standalone server, dart pub global activate mcp_dart_cli then mcp_dart create my_server (the CLI needs Dart 3.12; the generated project adds args and logging and targets Dart 3.4). Adding a server to an existing package needs only dart pub add mcp_dart.
  • Tool classes are adapters: parse arguments, call a domain service, map domain failures to CallToolResult(isError: true). Keep business rules, I/O and state in lib/src/ so they are testable without MCP.
  • Build services once in bin/server.dart and pass them to createMcpServer. Never create state inside a tool call or inside a Streamable HTTP serverFactory, which runs per request or session.
  • Read configuration and secrets at startup (arguments, environment) and pass them in. Never log secrets or read them inside handlers.

Read the full file on GitHub · 489 lines

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. 1mo ago First seen · 489 lines · 68 tokens per session scan A e3e9dc23d497

Subscribe to this mod's changes

mcp-dart-server is a skill published in the GitHub repository leehack/mcp_dart (116 stars, last pushed 3d ago), licensed MIT. It adds 68 tokens to every session and 4,011 once invoked, about $0.0003 per session on Opus 5.5. 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 2026-09-29.

Backend and APIsBuilding agents
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