majiayu000 Context Grounding
Read first. Quote second. Claim third. Never skip a step.
The grounding technique
Before making any claim about code, follow this sequence:
Step 1: Read the source
Read the actual file. Don't work from memory.
Step 2: Extract the relevant quote
Pull the exact text that supports your claim. Include line numbers.
Step 3: Make your claim based on the quote
Now state what you believe, citing the quote as evidence.
Example
Wrong approach: "The auth middleware checks for JWT tokens and returns 401 if invalid." (No evidence. Could be hallucinated.)
Grounded approach: "Reading src/middleware/auth.ts:15-25, the middleware does:
const token = req.headers.authorization?.split(' ')[1];
if (!token) return res.status(401).json({ error: 'No token provided' });
So it extracts the Bearer token from the Authorization header and returns 401 if missing."
When to ground
Always ground when:
- Answering questions about specific code behavior
- Writing code reviews or change proposals
- Explaining how something works
- Describing bug causes
- Making security assessments
Grounding for long documents
For files over 100 lines:
- Read the full file first to understand structure
- Identify the specific section relevant to the question
- Re-read that section carefully
- Extract the key lines as quotes
- Build your answer from those quotes
For files over 500 lines:
- Use Grep to find the relevant section
- Read just that section (use offset and limit)
- Extract quotes from what you read
- If you need more context, read surrounding sections
- Never make claims about sections you haven't read
The grounding test
Before sending a response, test each factual statement: "Could someone verify this by reading the file I'm referencing?"
If yes: the statement is grounded. If no: you need to add the file reference and relevant quote. If you don't have a file to reference: either find one or mark as unverified.