The last of the 1b split. Journey step 4 and `COHERENCE.md` §18: a
fresh `pmacs` greets the user with an empty buffer, an empty status
line, and no indication that `M-x` exists — the sole discovery
affordance in the product is knowing to press it.
Three findings shape the design:
- The existing step-2 ratchet pin collides with any welcome. It asserts
`status.is_empty()` while its own message says "reports no error" —
the same predicate only while nothing writes a non-error status at
startup. The framing corrects the assertion to its message's claim
and names that as the one existing assertion the stage changes,
rather than burying it in a diff.
- `C-h` is not free. It is bound to word-delete because non-kitty
terminals cannot disambiguate Ctrl+Backspace from Ctrl+H — both
produce byte 0x08 — so rebinding it to a help prefix would break
Ctrl+Backspace on every legacy terminal. §2's step-4 row calls it an
oversight; it is a deliberate trade with a stated rationale. The
help-prefix decision is deferred to the discovery arc with the
constraint recorded so it is inherited rather than rediscovered.
- A `*help*` buffer mechanism already exists over `src/help.rs`, so the
welcome can point at something real. Its two gaps are recorded rather
than inherited silently: it writes with delete/insert instead of
`set_generated_contents`, and it is found by name.
The welcome deliberately does NOT use `set_generated_contents`: that
lifts read-only, discards history and marks the buffer generated, all
wrong for the buffer step 5 requires the user to type into immediately.
Step 4 stays Partial — the row names a welcome, a cheat sheet and
`C-h`, and this closes the first plus a minimal second — so this is the
first 1b stage with no landed-evidence obligation on merge.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Lv428Fth9LRtffwJSsqH7T
