(likely cosmetic) The UNSUPPORTED remedy says 'create a manual OPENANT.md override file' but not what it must contain — and seven near-miss override shapes are skipped silently (only a missing key inside a parsed fence warns)

[gadievron]

Summary (likely cosmetic)

The UNSUPPORTED remedy says "create a manual OPENANT.md override file" but
not what the file must contain — and the override loader skips seven
near-miss shapes silently (no warning): prose-only, an uppercase JSON fence tag, an untagged fence, an unclosed fence, a BOM before YAML
frontmatter, a leading blank line before frontmatter, and an empty file.
Only one failure mode warns (a missing key inside an otherwise-parsed fence).

Mechanism (at ad2bb7e)

1. context/application_context.py:106 — the remedy line: "To analyze this
   repository, create a manual OPENANT.md override file." No shape stated.
2. The loader (check_manual_override, :661-714): .md via a json fence
   (the re.search at :695) or YAML frontmatter (the re.match at
   :701), .json directly (:687-689); the except at :710 warns on
   parse errors — but a file whose fence/frontmatter did not
   match falls through both ifs to the return None at :713 with no
   warning (the only continue, at :685, is the file-absent branch).

Executed at ad2bb7e

$ python3 override_matrix.py
json fence                   -> parsed type=library [silent]
YAML frontmatter             -> parsed type=library [silent]
.openant.md lowercase        -> parsed type=library [silent]
CRLF file                    -> parsed type=library [silent]
BOM + json fence             -> parsed type=library [silent]
prose only                   -> None               [silent]
uppercase JSON fence tag     -> None               [silent]
untagged fence               -> None               [silent]
unclosed fence               -> None               [silent]
BOM + YAML frontmatter       -> None               [silent]
leading blank line           -> None               [silent]
empty file                   -> None               [silent]
fence missing purpose        -> None               [WARNED]

override_matrix.py — full script

#!/usr/bin/env python3
"""The override-file acceptance matrix: which shapes parse, which warn, which
silently skip. Run from the OpenAnt checkout root."""
import os, sys, json, tempfile, io, contextlib
sys.path.insert(0, "libs/openant-core")
from pathlib import Path
from context import application_context as ac

fence = chr(96) * 3
body = {"application_type": "library", "purpose": "probe"}
cases = [
  ("json fence",                 "OPENANT.md", "# ctx\n" + fence + "json\n" + json.dumps(body) + "\n" + fence + "\n"),
  ("YAML frontmatter",           "OPENANT.md", "---\napplication_type: library\npurpose: probe\n---\n"),
  (".openant.md lowercase",      ".openant.md", fence + "json\n" + json.dumps(body) + "\n" + fence + "\n"),
  ("CRLF file",                  "OPENANT.md", ("---\napplication_type: library\npurpose: probe\n---\n").replace("\n", "\r\n")),
  ("BOM + json fence",           "OPENANT.md", "\ufeff" + fence + "json\n" + json.dumps(body) + "\n" + fence + "\n"),
  ("prose only",                 "OPENANT.md", "# My app\nThis is a library.\n"),
  ("uppercase JSON fence tag",   "OPENANT.md", fence + "JSON\n" + json.dumps(body) + "\n" + fence + "\n"),
  ("untagged fence",             "OPENANT.md", fence + "\n" + json.dumps(body) + "\n" + fence + "\n"),
  ("unclosed fence",             "OPENANT.md", fence + "json\n" + json.dumps(body) + "\n"),
  ("BOM + YAML frontmatter",     "OPENANT.md", "\ufeff---\napplication_type: library\npurpose: probe\n---\n"),
  ("leading blank line",         "OPENANT.md", "\n---\napplication_type: library\npurpose: probe\n---\n"),
  ("empty file",                 "OPENANT.md", ""),
  ("fence missing purpose",      "OPENANT.md", fence + "json\n" + json.dumps({"application_type": "library"}) + "\n" + fence + "\n"),
]
for label, fn, content in cases:
    d = Path(tempfile.mkdtemp(prefix="mx.", dir=os.environ.get("TMPDIR")))
    (d / fn).write_text(content)
    err = io.StringIO()
    with contextlib.redirect_stderr(err):
        ctx = ac.check_manual_override(d)
    outcome = ("parsed type=" + str(getattr(ctx, "application_type", None))) if ctx else "None"
    warn = "WARNED" if err.getvalue().strip() else "silent"
    print(f"{label:28s} -> {outcome:18s} [{warn}]")

The ask (two halves)

1. The remedy line names the required shape — a fenced JSON block or YAML
   frontmatter declaring application_type and purpose (a one-line fix at
   :106).
2. A discovered override file that fails to load warns. Every silent shape
   in the matrix falls through the same two missed ifs to the one
   return None, so a single warning on that path covers all seven — the
   way the missing-key parse error already warns. (A maintainer who instead
   widens the matcher — the BOM-before-frontmatter and leading-blank-line
   cases are matcher quirks — makes those shapes parse, which equally
   removes their silence.)

Falsifier

The remedy naming the shape, and the fall-through path at the loader
warning (or the matcher widened so the quirk shapes parse). Authored at
filing time; no falsifier existed in the source record.

Prior art

None on the message or the loader's silence. An earlier one-line version of
this note landed in #720's thread (the UNSUPPORTED raise is that issue's
trigger); this issue supersedes it — the silent-skip set measured here is
broader than that note's "prose-only", and the remedy belongs to this file,
not that mechanism.

Fix-direction: neither — diagnostics and wording; no finding changes.