Closes the gap that made optional inputs unusable: rendering rule 5.1(4)
made any unresolved placeholder an error while inputs had no `default`, so
an input marked `required: false` and referenced from the template failed
every render in which the caller omitted it — including the spec's own
section 4 example.
Section 10 already carried the derivation mechanism (`requirement: generate`,
resolution deliberately undefined), so a derived default needed a binding
rather than a new concept: the input's default names a declared prompt
dependency.
Spec:
- 5.1 rewritten as "Resolution and rendering". Resolution may be
non-deterministic and must report what it derived; rendering is
deterministic and must not derive. A tool that handles only supplied
values and static defaults is stated to be conforming.
- 6.1 (new) covers both declaration forms. Reference form is preferred, with
the reason stated — an inline prompt is anonymous, so unversioned,
unprovenanced and un-evaluable — and validators should warn when a
published package derives inline.
- A derived default may declare a static fallback `value`. Without one the
input stays unresolved, which is an error; derivation never silently
yields empty content.
- 4, 10, 18 (rules 11-13), 19 (two new MUST NOTs), 21 updated accordingly.
Reference CLI:
- New `resolve` verb reporting the origin of every value.
- `Resolution` dataclass and `resolve_inputs`; `resolve_values` kept as a
wrapper so existing callers are unaffected.
- `render` refuses with a specific error naming underivable inputs rather
than substituting empty text.
- Tests 3 -> 11. Example package lifecycle re-verified end to end.
INTENT.md is unchanged: splitting resolve from render preserves success
criterion 4 (deterministic rendering) as written.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Bjefh8NUiEiahN4JLwoSKM
Assistant: claude-code
Assistant-Model: opus
Assistant-Process: 388925@bnt-lap001
Assistant-Session: 3507023f-e0fd-4a1e-9d90-a0d4217d1502