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What Fills the Context Window
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2. Context and Project Instructions · 1 of 4
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Orient
Startup cost, then everything you add
Find out where an hour of session went
Predict
Measure your own startup cost
Close
Practice
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What Fills the Context Window
Beginner
☆
📑
Almost every best practice in this course exists because of one constraint
Orient
Startup cost, then everything you add
Find out where an hour of session went
Predict
Measure your own startup cost
Close
Practice
Related
Practice activities and scenarios are optional. Mark the lesson complete after reading, and return to practice whenever it helps.
Restoring your saved work…
07
Optional practice
🧠 Optional scenario practice
Q1
Which of these does NOT consume your main conversation's context window?
A
A file Claude reads with the Read tool
B
The exploration a subagent performs before returning its summary
C
Your project's CLAUDE.md
D
The stdout of a test run
Q2
You connect five MCP servers but use only one. What is the default context cost of the four idle servers?
A
Their full JSON tool schemas, loaded at startup
B
Roughly their tool names — full schemas stay deferred until a tool is used
C
Nothing at all until you run /mcp
D
The same as an equivalent number of file reads
08
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Beginner
Clear, Compact, Rewind
Intermediate
CLAUDE.md That Gets Followed
Intermediate
Auto Memory and Scoped Rules
📝 Notes
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