Measured: an R12 (AC1009) document has no OBJECTS section, so ezdxf exports
neither AcDbVariableDictionary/DICTIONARYVAR nor the seeded SCALE objects, and
drawing_save_as keeps AC1009. `_set_annotation_scale` reported `ok: True,
changed 1:1 -> 1:50` and the file reloaded as 1:1 -- the header-only write
that vanishes on reload, the class this task exists to remove, and a breach
of the backend's own R12 honesty convention (viewport_set_scale / lock).
The write is now refused with a ValueError naming R12 and "save as R2000 or
newer", after parse_scale (a malformed value is still named as such) and
before either dictionary is touched, so a refused call leaves the root
dictionary as it found it and drawing_settings still applies the sibling keys
(limits / grid / ortho survive R12). The refusal is listed with the others in
the contract and server docstrings. Pinned by two tests that save, reopen and
read the R12 file back.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
An ezdxf-authored drawing has no ACAD_SCALELIST entries, and
`_ensure_scale_entry` appended only the requested scale. AutoCAD repopulates
its default list only when the dictionary is *empty*, so the saved file
opened with a one-entry scale list and `SetVariable("CANNOSCALE", "1:1")`
failed with `Error setting system variable` -- the annotation scale could
no longer be changed in AutoCAD, while the tool reported `ok: True` and the
test pinned the degraded state (`len(keys) == 1`).
An empty list is now seeded with AutoCAD's own default metric list before
the requested scale is considered: the 17 entries a fresh AutoCAD 2026
drawing carries (`Documents.Add()` saved as DXF, MEASUREMENT 1), in that
order and under AutoCAD's own keys A0 ... A9, B0 ... B6. New entries take
the next key in that sequence (`_scale_list_key`) instead of being keyed by
their name; presence is still decided by group 300, so a non-empty
AutoCAD-authored list is never re-seeded or duplicated. Verified live: the
headless file now opens in AutoCAD 2026 with the 17 keys, CANNOSCALE 1:50
current, and switching to 1:1 and 1:100 works.
Tests: the fresh-drawing test asserts the seeded names and keys, that
setting 1:50 appends nothing (it is a default), that 1:25 lands under B7
once, and that the list survives save + reopen with 1:1 present; a new test
pins that *reading* the annotation scale creates nothing (the read side
stays pure, AutoCAD fills an empty list itself); the AutoCAD-keyed list test
now expects the A3 key. The `drawing_settings` docstring says what each
engine does and that AutoCAD refuses the live write on a paper-space layout
with no active viewport (measured).
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
The tuple/list branch put the win32com VARIANT built for SetVariable into the
returned dict. The system_set_variable tool returns that dict verbatim under
output_schema {"type": "object"}; pydantic cannot serialise a VARIANT, FastMCP
drops the structured content and the client sees "outputSchema defined but no
structured output returned" -- after AutoCAD had already applied the write, so
every raw point-variable write (LIMMIN, LIMMAX, GRIDUNIT, SNAPUNIT, INSBASE)
was a retry/undo trap on the live engine while the audit log said TOOL OK.
The VARIANT is now only the SetVariable argument; "value" carries the
coerced Python list. The fake-ActiveX test asserts the reply, and a new
Client(server.mcp) test drives the tool through the output schema so the
serialisation path is covered.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
`_ensure_scale_entry` decided "already present" with `scales.get(name)`, a
lookup by DICTIONARY key. AutoCAD saves ACAD_SCALELIST keyed A0, A1, ... with
the scale name only in the SCALE object's AcDbScale group 300, so on any
AutoCAD-authored drawing (whose default metric list already carries 1:1 ...
1:100, 2:1) the check never matched and every `annotation_scale` write
appended a second SCALE object with the same name.
Presence is now decided by iterating the list and reading each entry's
group-300 name (`_scale_entry_name`, which reads the DXFTagStorage subclass
ezdxf loads SCALE into). A genuinely new entry is still keyed by its name
(the plan's test contract); if that key is somehow taken it falls back to
the next free `A<n>` slot like AutoCAD.
Regression test seeds an A0/A1/A2-keyed list the way AutoCAD writes it and
asserts: an existing 1:50 is reused (no new key, exactly one object named
1:50), a missing 1:25 is appended exactly once and is idempotent, and the
file round-trips with a clean audit.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
Headlessly, grid/snap are stored on the active VPORT, CANNOSCALE in
AcDbVariableDictionary (+ an ACAD_SCALELIST entry), and LIMMIN/LIMMAX on
the model-space layout as well as the header — measured: the header alone
is overwritten at save. Registry-saved variables (AUTOSNAP, POLARANG, …)
are refused with capability registry_sysvar instead of vanishing.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
