---
name: mz-adapter-guide
description: >
  Correctness invariants + architecture: adapter, coordinator, pgwire, peek
  paths, timestamp oracle. Trigger: questions about these subsystems —
  "how does coordinator work", "what are read holds", "explain peek path",
  "how does timestamp selection work", "why does this query block". Also
  edits in src/adapter/, src/pgwire/, src/timestamp-oracle/.
---

# Adapter Guide Skill

When working on the adapter layer or related crates, always read and follow the
guidance in `doc/developer/guide-adapter.md` before making changes. That
document contains correctness invariants, architectural notes, and a list of
optimizations that have been tried and rejected for correctness reasons.

Read `doc/developer/guide-adapter.md` now.

When working on the timestamp oracle (`src/timestamp-oracle/`), also read the
module-level docs in `src/timestamp-oracle/src/lib.rs` and
`src/timestamp-oracle/src/batching_oracle.rs` for the `TimestampOracle` trait
contract and the batching/linearizability invariants.

When you or the user discover that an approach is incorrect or heading in a
wrong direction, suggest distilling the learning into
`doc/developer/guide-adapter.md`. Add it to whichever section fits best — a
new correctness invariant, a new subsection under an existing invariant, a
rejected optimization, or a new top-level section if needed. Describe what was
tried, why it's wrong, and any relevant context. This keeps the guide up to
date and prevents future re-discovery of the same pitfalls.