Context Docs

Purpose

Large centralized documentation files consume too much context window. Decentralized, module-specific context docs provide targeted information exactly when an agent needs it.

When to Use

• A module's boundaries or invariants keep being rediscovered the hard way
• Onboarding or agent sessions repeatedly ask the same questions about a subsystem
• After a refactor changed how a module communicates with the rest of the app

Inputs

• The subsystem directory and its public interface
• Existing docs, to avoid duplicating the central README or architecture docs

Workflow

1. Decide where the context belongs. Module-specific knowledge goes in a context file inside the subsystem directory (e.g., src/auth/CONTEXT.md); repo-wide knowledge belongs in the central README or architecture docs — one home per fact, never both:

   find src -iname "CONTEXT.md" -o -iname "README.md"   # existing context docs
   rg -ln "<module name>" docs/                         # already documented centrally?
   

2. Document only the boundaries. How does this module communicate with the rest of the app? What are its critical invariants? Not implementation detail the code already states.

3. Keep it terse. Bullet points and exact file paths. No transient notes — session state, TODO lists, and progress logs belong in handoff documents, not context docs.

4. Validate every path the doc references:

   rg -no "src/[A-Za-z0-9_./-]+" src/auth/CONTEXT.md | sort -u   # referenced paths
   test -f src/auth/session.ts && echo OK                        # confirm each exists
   

5. Update these files inline when refactoring the module. A context doc that lags the refactor is worse than none.

Output

• A short, boundary-focused context file inside the subsystem directory
• Stale or central-doc-duplicating content removed or relocated

Verification

• Doc lives inside the subsystem it describes
• Content is boundaries and invariants, not implementation detail or transient notes
• Every referenced file path verified to exist
• No duplication of central docs — one home per fact
• Doc updated in the same change set as the refactor that affected it

Failure Modes

• Context dumping — pasting session notes or progress logs into a context doc; that is a handoff, not context.
• Central duplication — the same fact in the central README and the module doc, guaranteed to diverge.
• Path rot — referenced files moved since the doc was written; validate paths on every touch.
• Novel-length context — if it doesn't fit on a screen, agents won't load it when they need it.