design-mcp-server

design-mcp-server is a skill for Claude Code from cyanheads/obsidian-mcp-server. It costs 62 tokens per session (19,742 once invoked), scanned A, original, Apache-2.0.

A planning guide for designing a new MCP server, which lets an AI assistant use an API, database, or other system. It creates a design document before implementation.

In plain words
What is it for?
Planning the tools, data access, limits, and users of a new MCP server or a major new server area.
Why use it?
It helps decide what the server should expose and who it is for before coding begins. This reduces unclear scope and poorly planned tools.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions Claude Code.

Part of the obsidian-mcp-server plugin — 33 skills, 1 MCP server shipped together

Good fit Planning the tools, data access, limits, and users of a new MCP server or a major new server area.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/cyanheads/obsidian-mcp-server/design-mcp-server
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 cyanheads/obsidian-mcp-server --skill design-mcp-server
Clone the repo
git clone --depth 1 https://github.com/cyanheads/obsidian-mcp-server

Made for: Claude Code.

Or install obsidian-mcp-server, the plugin that ships this one along with the rest of its 33 skills, 1 MCP server.

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 design-mcp-server

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/cyanheads/obsidian-mcp-server/design-mcp-server"><img src="https://agentmods.dev/badge/skills/cyanheads/obsidian-mcp-server/design-mcp-server.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 62 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 19,742 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 2 findings, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Tool Misuse · line 653
    Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).
    Fix: Validate all tool parameters against an allowlist. Reject dangerous parameter values (shell=True, --force, -rf /) and use safe defaults.
  • medium Excessive Agency · line 508
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
How audits are shown
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 $0.00062 $0.19742
Opus 5.5 $0.00025 $0.07897
Sonnet 5.5 $0.00012 $0.03948
Haiku 4.5 $0.00006 $0.01974

Measured yesterday against content hash e4748940dfc6, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

design-mcp-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 yesterday.

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.

Origin

Copies of this mod

8 near-identical copies found in the catalogue:

framework-skills/design-mcp-server/SKILL.md · 722 lines

How it starts

The opening of the file, as written. The whole thing — 722 lines — stays where its author put it; the contents beside it link to each section on GitHub.

When to Use

  • User says "I want to build a ___ MCP server"
  • User has an API, database, or system they want to expose to LLMs
  • User wants to plan tools before scaffolding
  • Existing server needs a new capability area — two or more tools sharing a new noun or service, or any new upstream source (design the addition, not just a single tool)

Do NOT use for a single tool on an existing noun — use add-tool directly.

Inputs

Gather before designing. Ask the user if not obvious from context:

  1. Domain — what system, API, or capability is this server wrapping? Or is the server providing internal capability with no external dependency (computation, text/code utilities, in-memory state)?
  2. Data sources / source of truth — APIs, databases, file systems, external services? Or is the server itself the source (in-memory state, pure computation, local-only utility, embedded model)?
  3. Target users — what will the LLM (and its human) be trying to accomplish?
  4. Scope constraints — read-only? write access? admin operations? what's off-limits?
  5. Deployment — local stdio, hosted HTTP, Cloudflare Workers? The answer gates primitives: DataCanvas and MirrorService don't run on Workers, and a tool that asks the caller for input mid-call needs a stateful HTTP session (see the Client round-trip row in Step 3).

If the domain has a public API, read its docs before designing. For internal-only servers, skip API research and go straight to user goals. Don't design from vibes either way.

Server scope and audience

Before committing to a server boundary, answer: what workflow does this server serve, and who is the audience?

The unit of a server is a user workflow, not an API. A single rich API can earn its own server when the audience is large and the API surface supports a full workflow (PubMed for literature research, SEC EDGAR for financial analysis, Shodan for internet-wide device intelligence). Multiple APIs should collapse into one server when they serve the same workflow from different angles — a "threat intelligence" server that aggregates VirusTotal, AbuseIPDB, and GreyNoise is more useful than three separate servers because the user's goal is "assess this indicator," not "query VirusTotal."

Read the full file on GitHub · 722 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. yesterday Changed · +1 lines e4748940dfc6
  2. 20d ago Changed · +27 lines e97d277ea950
  3. 1mo ago Changed · +17 lines ff2e1fa6875e
  4. 1mo ago Changed · -42 lines 08d0f2d4ad13
  5. 1mo ago Changed · +5 lines 8e58c655352e
  6. 1mo ago Changed 84044a901bd8
  7. 1mo ago First seen · 714 lines · 62 tokens per session scan A 27b9a61334d6

Subscribe to this mod's changes

design-mcp-server is a skill published in the GitHub repository cyanheads/obsidian-mcp-server (701 stars, last pushed yesterday), licensed Apache-2.0. It adds 62 tokens to every session and 19,742 once invoked, about $0.0002 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 2026-08-30.

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