PLAN.md

@@ -721,6 +721,70 @@ between `compact` and `checkpoint`; it is out of this scope because it wants
 its own design pass, and because the free list must not add a second instance
 of the same shape.
 
+### The spec runner starts reading `expectEvents`
+
+354 of the 487 cases declare `expectEvents` and the runner read none of them,
+so a case could send the wrong command entirely and still be counted a pass as
+long as the result came back right. The old `pass` column was an upper bound by
+construction and said so; it is now an assertion that the engine answered
+correctly **and** was asked the right question. **Scorecards recorded before
+this are not comparable with ones recorded after.**
+
+The totals moved 168/124/195 → 194/97/196 across the commits, but the path
+matters more than the endpoints: turning the assertion on cost 34 passes, and
+every one of them was a defect the result column could not see.
+
+What it found, in the order it found them:
+
+1. **The runner dropped `collectionOptions`.** Every collection entity was
+   built as `db.collection(name)`, so the 15 entities declaring
+   `writeConcern: {w: 0}` never got it — **every "unacknowledged write" case in
+   the corpus was running an acknowledged write.** They passed because the two
+   produce results a `$$unsetOrMatches` expectation accepts either way. Only
+   the command on the wire distinguished them, and nothing read the command.
+2. **The wire version disagreed with the version string.** `buildInfo` said
+   4.4.0, the handshake said maxWireVersion 8, which is 4.2. A driver believes
+   the wire version: it refused *client-side* to send `hint` on an
+   unacknowledged delete or findAndModify, and withheld `comment` from
+   getMore, listCollections and listDatabases. 16 cases. The 8 was not
+   arbitrary — it was tied to keeping drivers off the streaming hello protocol
+   — but that turned out to rest entirely on omitting `topologyVersion`, which
+   is checked in the driver and is the whole mechanism. A test now asserts the
+   two numbers agree, since drifting apart silently was the actual defect.
+3. **`$$unsetOrMatches` was changing root-ness.** The operator wraps a value,
+   it does not reposition it; the runner matched what stood behind it as a
+   nested document. 25 cases, all of them results the engine had right.
+4. **An event's command is not the shape the driver sends.** A sort is held as
+   a JS `Map`, so `Object.keys` on it is empty and every expected key read as
+   missing. It hides well: EJSON prints a Map exactly like a document, so the
+   event dump reads as evidence the matcher is wrong about something else.
+
+Two assertions are declined, both enumerated in the runner and in
+`scorecard.txt`, and neither can hide anything the engine did:
+
+- **`maxTimeMS`** — the harness's own doing. Every client carries CSOT
+  `timeoutMS`, which overwrites `maxTimeMS` with the remaining budget, so the
+  value on the wire is ours. Refused unconditionally rather than only when it
+  would fail, so it cannot become a pass by coincidence. One case, and dropping
+  `timeoutMS` instead would cost far more — it is what replaced the outer race
+  that once produced ~190 phantom timeout FAILs.
+- **`cmap`/`sdam` event types, `ignoreExtraEvents`, `hasServiceId`,
+  `hasServerConnectionId`** — none occurs in this corpus; reported unsupported
+  where asserted rather than waived.
+
+**Left failing on purpose: `bypassDocumentValidation: false`, 4 cases.**
+mongodb@7.5.0 strips the field unless it is exactly `true` on the bulk and
+findAndModify paths (`lib/bulk/common.js:292`,
+`lib/operations/find_and_modify.js:19`) while sending it correctly for single
+-document operations, so 4 sibling cases pass and 4 fail on a difference that
+is entirely the driver's. The field is built client-side and never reaches the
+engine. A refusal was written and thrown away: made unconditional it also
+skipped the 4 that legitimately pass, and made conditional it would be a
+skip-when-it-would-fail rule, which is the shape that turns a scorecard into
+flattery. Four undeserved entries in the fail column is the cheaper error, and
+this note is the correction. Revisit when the driver is bumped — which already
+has to be its own commit with its own re-recorded scorecard.
+
 ---
 
 ## 6. Deferred designs (grill each at its milestone)
@@ -759,10 +823,11 @@ of the same shape.
     the anchor rewritten — resuming at it returned updated documents twice,
     caught by draining a collection being updated underneath.
 
-  Still open in M1: the doc-level free list, sessions plumbing (`lsid`
-  accepted), and command-monitoring (`expectEvents`) in the spec runner. The
-  eight reclamation bugs above were cleared first, as preconditions for the
-  free list rather than as work of their own.
+  Still open in M1: the doc-level free list and sessions plumbing (`lsid`
+  accepted). The eight reclamation bugs above were cleared first, as
+  preconditions for the free list rather than as work of their own;
+  command-monitoring (`expectEvents`) landed next, so that the free list and
+  sessions are measured by an instrument that is no longer known to overstate.
   **A prerequisite the free list must honour**, recorded here while it is
   still being designed: *an offset that was ever a record start must remain a
   record start.* `doc_bytes` reads a `u32` length prefix in place, so an