[jyviko]

Adds a rule to AGENTS.md §4b, Root causes, not point solutions:

• If a fix turns into try-then-fallback, a retry, a chain of methods tried in turn, or a branch for one case, that's a code smell. Find the construction that's wrong and fix it as a whole.
• Fillets and chamfers follow the generic rolling-ball blend that is replacing SMLib's fillet code step by step (hub Port smlib#76: generic blend step 1, the tangent end as an event of the trace (G2 end rib in t = √s) #2243). A failing case points to the part of that one construction that is wrong for it, and never gets a special case.
• Before designing a geometry fix, search the literature for the problem.
• Before building, check open PRs, issues and the area's hub for contributors working on something similar, and build on their work.

Text only; no code changes.

🤖 Generated with Claude Code

https://claude.ai/code/session_01DtL5M41G8Nua7HvuFPZkmJ

[bherbruck]

Approved by the automated first-pass review: CI green, mergeable, no CI/build/dependency file changes, no red-flag patterns in added code (process/network/env/unsafe outside FFI/blobs/hidden unicode), 0 known-mismatch entries added. Logic is gated by CI and the difftest merge queue.