0004. The model edits text and has no tool catalog

Context

The obvious design hands the model the same actions the editor dispatches: clip/trim, keyframe/add, a catalog of a hundred tools. OpenReel's agent does this. Models are measurably worse at choosing among many tools than at writing code, and a tool catalog has to be kept in sync with the vocabulary.

Decision

The model reads the file, replaces strings in it and writes it back. Its instructions are a prompt that explains the vocabulary and the conventions; the lint tells it what it got wrong. Actions are for the editor's gestures only.

Consequences

• The model can do anything the vocabulary allows in one edit, including restructuring, which no tool catalog expresses well.
• A model edit replaces the tree: the executor's log and history are cleared (replaceTree), so a gesture in flight must be folded first (0003).
• The quality of the prompt is a product surface; it lives next to the example that was written from it.

Alternatives

A tool per action: rejected for the reasons above. A hybrid where the model emits actions for small changes: not worth two code paths.