Glossary — M

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Markdown

A lightweight plain-text format that converts to HTML. # Heading, **bold**, [link](url), - bullet point. Invented by John Gruber in 2004. Used for READMEs, documentation, blog posts, AI tool memory files. This entire encyclopedia is written in Markdown.

See also: Memory system


MCP (Model Context Protocol)

A standardized protocol — invented by Anthropic in 2024 — that lets any LLM agent talk to any tool, data source, or service through a common interface. Think “USB-C for AI tools.” If you build an MCP server for your service, any MCP-compatible AI (Claude, ChatGPT desktop, Cursor, etc.) can use it without custom integration work.

See also: MCP, Tool use, Agents


Memory (Claude Code)

The persistent knowledge files Claude Code reads at the start of every session. CLAUDE.md holds project-specific rules and context. MEMORY.md is the index of auto-memory entries. The memory/ folder holds individual entries (user_*.md, project_*.md, feedback_*.md, reference_*.md). All Markdown, all human-editable.

See also: Memory system


Memory (ChatGPT, Claude — AI assistant memory)

A feature in consumer AI assistants where the AI remembers information about you across separate conversations. Different from Claude Code’s project memory (above) — this is consumer-product memory for personal use. ChatGPT lets you see and edit what it’s saved; Claude has Memory in Projects.

See also: ChatGPT Memory, Claude consumer


Multimodal AI

AI that processes more than one type of input (text + images + audio + video). GPT-4o, Claude 3.5+, and Gemini are multimodal — you can paste images and they understand them. The future is increasingly multimodal: voice in, voice out; images understood; video processed. The opposite is unimodal — text-only, image-only, etc.

See also: Multimodal (vision, audio), Real-time voice AI


Method (HTTP)

The verb part of an HTTP request: GET, POST, PUT, PATCH, DELETE, OPTIONS, HEAD. Tells the server what kind of operation the client wants to perform. GET reads, POST creates, PUT replaces, PATCH partially updates, DELETE removes.

See also: HTTP, REST


Middleware

A function that sits in the middle of the request/response cycle, intercepting requests before they reach the handler (or responses before they reach the client). Used for auth checks, logging, redirects, header tweaks. Next.js has a special middleware.ts file at the project root.

See also: Next.js, Backend


Migration

A versioned, replayable change to your database schema. Adding a column, creating a table, adding an index — all migrations. Each migration is a script with an “up” (apply) and ideally a “down” (revert). Lets you bring any database (local, staging, production) to the same schema state by replaying the same migrations in order.

See also: Migrations


Module

A file (or sometimes a folder) that exports things other files can import. The unit of code organization in modern JavaScript. See ES Modules for the standard import/export syntax.

See also: ES Modules, Package


Monorepo

A single Git repository that contains multiple related projects (e.g. a web app, a mobile app, a shared design system, several backend services). Managed by tools like Turborepo, Nx, or pnpm workspaces. Trade-off: easier coordination across projects, harder to keep things simple.

See also: Git


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