Model Context Protocol
Model Context Protocol (MCP) is an open standard that connects AI apps to tools, data sources, and workflows through clients and servers. We adopt it as the default tool-connectivity layer for coding agents in this estate.
Blurb
MCP (Model Context Protocol) is an open-source standard for connecting AI applications to external systems.
Summary
When to use:
| Situation | Notes |
|---|---|
| Shared tools across hosts | One server; many clients (Claude Code, Cursor, Codex, Gemini) |
| Vault / local integrations | Obsidian, Reminders, Gmail, and similar via local stdio servers |
| Remote product APIs | Prefer a vendor-hosted server over a locally installed package |
When to skip:
- One-off scripts where a CLI or SDK call is enough
- Untrusted third-party servers without review (treat tool surface as code execution)
- Vendor-provided Node.js packages when a maintained hosted endpoint is practical
- Replacing portable behavior that belongs in Agent Skills Framework (
SKILL.md)
Trade-offs: MCP standardizes what tools an agent can call. Skills standardize how the agent reasons. Prefer MCP for actions and data access; prefer skills for reusable procedures.
Locally installed MCP packages add a software supply-chain risk to every client machine. Prefer vendor-hosted endpoints when available. Pair local servers with dependency controls, least privilege, and Claw Patrol or equivalent safeguards.
Contrast: Agent Client Protocol is about treating an agent as a service. MCP is about plugging tools and context into an agent host.
Details
Shape
| Role | Responsibility |
|---|---|
| Host / client | Agent app that discovers tools, prompts, and resources |
| Server | Exposes tools, resources, and prompts over stdio or HTTP |
| Transport | Local stdio is common for desktop agents; remote HTTP/SSE for hosted servers |
Estate Notes
- This vault declares MCP servers in
.mcp.json(Obsidian vault access and related tooling). - Coding agents in the garden (Claude Code, cursor-agent, Codex, Gemini) all speak MCP for extensions.
- Agent Skills - Sources treats MCP servers as the complement to skills: tools vs reasoning.
Security
- Every connected server expands the agent’s blast radius (files, shell, cloud APIs).
- Vendor-distributed Node.js servers create a supply-chain path through package installation and transitive dependencies.
- Prefer vendor-hosted endpoints. Report locally packaged servers to vendors when a hosted service is practical.
- Prefer least privilege, allowlists, and human approval for destructive tools.
- See Claw Patrol when evaluating egress and protocol-aware interception for agent workloads.