Two tools with reasonable descriptions but critical schema gaps. Tool names follow verb_noun pattern (cinemachine-add-extension, cinemachine-brain-ensure) but descriptions lack actionable detail on when to use each vs. the other. Input schemas visible but incomplete: GameObjectRef type is custom and undocumented; no output schemas provided. Parameters lack type constraints (extensionTypeName is free-form string with no enum of valid types). Error handling and recovery guidance absent. No evidence of idempotency markers or destructive operation warnings despite WRITE risk classification.

• Define GameObjectRef schema explicitly: is it a string (GameObject name/path), a UUID, or an object with {name, id} fields? Document in parameter description.
• Add output schema for both tools. cinemachine-brain-ensure should document: returns {brainId, cameraRef, isNewBrain}. cinemachine-add-extension should return {extensionId, extensionType, gameObjectRef}.
• Replace extensionTypeName free-form string with enum of valid Cinemachine extension types: ['CinemachineDeoccluder', 'CinemachineConfiner3D', 'CinemachineFollowZoom', 'CinemachineRecomposer', ...]. Or add a discovery tool list-cinemachine-extensions.
• Expand descriptions to 100-150 chars each. Include: WHAT it does, WHEN to call it (e.g., 'Call brain-ensure before add-extension'), and WHAT it returns. Example: 'Ensure a CinemachineBrain exists on the target Camera (required for any CinemachineCamera to drive rendering). Returns brain ID and camera reference. Call this first if you do not know whether a brain is already attached.'
• Add error recovery hints: 'If extension type is invalid, call list-cinemachine-extensions to see available types.' 'If GameObject not found, verify the reference path or use search-gameobject first.'