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Spell metadata kwargs๏
๐ก Intermediate ยท Lesson 06
Spell metadata via bind kwargs (landed 2026-07-19): any extra keyword on bind() threads into the Spell's own kwargs channel and lands on spell.metadata - tag your registrations with ownership, tiers, or agent breadcrumbs. Native bind values are unstealable: declared parameters capture their names before **kwargs collects.
Before you run๏
Use the Intermediate guide for prerequisite concepts. Run from a checkout with Melder installed and Python 3.14 free-threading selected. The collection download includes the level's local helper modules.
Run the saved script๏
python UX_and_AIX_experiences/02_intermediate/06_spell_metadata_kwargs.py
py -3.14t UX_and_AIX_experiences/02_intermediate/06_spell_metadata_kwargs.py
Public surface๏
bind(**extras) -> Spell.metadata, find_spell_by_spell_id
Code๏
1"""
2TIER: intermediate (06)
3GOAL: Spell metadata via bind kwargs (landed 2026-07-19): any extra
4 keyword on bind() threads into the Spell's own kwargs channel and
5 lands on spell.metadata - tag your registrations with ownership,
6 tiers, or agent breadcrumbs. Native bind values are unstealable:
7 declared parameters capture their names before **kwargs collects.
8SURFACE EXERCISED: bind(**extras) -> Spell.metadata, find_spell_by_spell_id
9"""
10import melder as md
11
12
13class PaymentsApi:
14 pass
15
16
17def main() -> None:
18 book = md.Spellbook()
19 spell_id = book.bind(
20 spell=PaymentsApi, existence="unique",
21 owner_team="payments", tier="gold", reviewed="2026-07-19",
22 )
23 spell = book.find_spell_by_spell_id(spell_id)
24 assert spell.metadata == {
25 "owner_team": "payments", "tier": "gold", "reviewed": "2026-07-19",
26 }
27 print("spell born with metadata:", spell.metadata)
28
29 try:
30 book.bind(spell=PaymentsApi, existence="unique", spell_id="jacked")
31 print("collision unexpectedly accepted")
32 except TypeError as err:
33 print("native Spell params stay sovereign:", type(err).__name__)
34
35
36if __name__ == "__main__":
37 main()
Check the outcome๏
The script contains its own assertions or demonstrated refusal paths. Run it to evaluate those checks against your installed version. The code above is taken directly from the saved file; no run output is invented here.