Eliminate the external kicad-sch-api dependency by migrating all MCP
tools to the internal SchDocument class built on sexp_tree.py. This
fixes three serialization bugs (dropped global labels, TypeError on
local labels, mis-quoted property private keywords) and removes ~1,900
lines of workaround code.
New modules:
- sexp_tree.py: S-expression parser and round-trip serializer
- sch_document.py: schematic read/write/mutate API
- lib_resolver.py: symbol library search and resolution
- sch_helpers.py: shared load/validate/expand helpers
Migrated all 9 tool files, resources, and tests. Removed 5 workaround
functions from sexp_parser.py. 531 tests pass, ruff + mypy clean.
snap_to_grid() used 2.54mm default grid for symbol position,
silently rounding sub-2.54mm stub lengths up and causing shorts
on tightly-spaced connectors. Now uses 1.27mm fine grid.
add_label bypasses kicad-sch-api serializer entirely — generates
s-expression strings and inserts them directly into the .kicad_sch
file via atomic write. Fixes two upstream bugs: global labels silently
dropped on save (serializer never iterates "global_label" key), and
local labels raising TypeError (parameter signature mismatch in
LabelCollection.add()).
add_power_symbol now falls back to sexp pin parsing when the API
returns None for custom library symbols (e.g. SMF5.0CA). Extracts
shared resolve_pin_position() utility used by both add_power_symbol
and batch operations.
Batch labels also fixed — collected as sexp strings during the batch
loop and inserted after sch.save() so the serializer can't overwrite
them.
kicad-sch-api has two parsing gaps: get_symbol_definition() returns
None for non-standard library prefixes (e.g. Espressif:ESP32-P4),
and there is no sch.global_labels attribute for (global_label ...)
nodes. This adds a focused parser that reads directly from the raw
.kicad_sch file as a fallback, integrated into the connectivity
engine, pin extraction, and label counting tools.
New modules:
- patterns/ library: decoupling bank, pull resistor, crystal oscillator
placement with power symbol attachment and grid math helpers
- tools/batch.py: atomic file-based batch operations with dry_run
- tools/power_symbols.py: add_power_symbol with auto #PWR refs
- tools/schematic_patterns.py: MCP wrappers for pattern library
- tools/schematic_edit.py: modify/remove components, title blocks, annotations
- resources/schematic.py: schematic data resources
43 new tests (99 total), lint clean.
