Claude Certified Architect – Foundations: the complete prep course

The repeating cycle behind any Claude-powered agent: send a request, check what Claude wants to do next (stop_reason), run a tool if asked, send the result back, repeat until Claude is done.

A field on Claude's response telling your code why it stopped talking — e.g. it wants to call a tool (tool_use), it finished (end_turn), or it ran out of room (max_tokens).

tool_use is Claude asking your code to run something (a search, a database lookup...). tool_result is your code's answer, sent back so Claude can continue.

A helper Claude spawns to do one focused piece of work in its own separate memory space, then reports back a summary — so the main conversation doesn't get cluttered with the helper's scratch work.

Small scripts that run automatically around a tool call — one right before it (can block it entirely) and one right after (can react to the result). Used for rules that must always hold, not just usually hold.

A standard way to connect Claude to external systems — databases, internal tools, company APIs — through a shared plug-in format instead of custom one-off code every time.

The three things an MCP connection can offer: Tools are actions Claude decides to call itself; Resources are data the surrounding app decides to hand Claude; Prompts are ready-made instructions a person picks, like a menu option.

A config file listing which external MCP connections a project uses — shared with the whole team via version control, with any secret keys kept out of it and read from environment variables instead.

A plain-text file Claude reads automatically at the start of every session in a project — the place for standing instructions like coding conventions or how the codebase is organized.

Instructions that only switch on for certain files (e.g. only when editing test files), instead of loading into every single session the way CLAUDE.md does.

A packaged set of instructions Claude loads by itself when a task matches, without anyone typing a command — think of it as an instruction manual Claude picks up automatically off the shelf.

Two different settings that sound alike: allowed-tools just skips the usual 'are you sure?' prompt for tools you've pre-approved — it doesn't block anything else. disallowed-tools is what actually removes a tool from what's available.

A mode where Claude describes what it's about to do and waits for a yes before touching any files — used for bigger or riskier changes, skipped for small obvious ones.

A cheaper way to send Claude a large pile of requests when nobody is waiting on the answer right away — costs about half as much, but can take up to a day to come back.

A way to avoid Claude re-reading the same large, unchanging block of text (like a system prompt or a codebase) on every single request — it's remembered for a while, which is both cheaper and faster.

The total amount of conversation and text Claude can 'see' at once for a given request. When a conversation runs long, older parts may need to be summarized or dropped to make room.

A setup where one coordinator agent hands out tasks to several helper agents and collects their answers — the helpers never talk directly to each other, only to the coordinator.

A design choice that looks reasonable but causes real problems in practice — this course names seven specific ones the exam likes to hide inside wrong answers.