Single tool 'diff_namespaces' has critical definition gaps. Tool name lacks action verb (should be 'compute_diff' or 'get_namespace_diff'). Description is minimal (8 words, well below 10-char baseline). Input schema present but parameters 'before' and 'after' lack descriptions entirely, only type 'object' with no guidance on expected structure. No output schema documented. No error handling guidance. Tool appears to accept arbitrary JSON objects with no validation hints, format constraints, or examples of valid input structure. This violates pattern:tool-description (every parameter needs description) and pattern:constrained-input (no guidance on what fields 'before'/'after' should contain).

• Rename tool to 'compute_namespace_diff' or 'get_namespace_diff' to start with action verb and clarify intent.
• Expand tool description to 100 - 200 chars: 'Computes the difference between two namespace state snapshots, identifying added, modified, and removed variables. Pass two snapshots (each a dict of variable names to {type, repr} objects) to detect state changes between execution steps.'
• Add descriptions to 'before' and 'after' parameters: 'before: Namespace snapshot before changes (dict mapping variable names to {"type": str, "repr": str}). Obtain via take_snapshot().' and similar for 'after'.
• Document output schema in tool description or as a separate schema field: 'Returns {has_changes: bool, added_count: int, modified_count: int, removed_count: int, added: dict, modified: dict, removed: dict}'.
• Add error handling: validate that 'before' and 'after' are dicts with 'type' and 'repr' keys per variable; return actionable error like 'Invalid snapshot format: expected {"var_name": {"type": str, "repr": str}, ...}' if structure is wrong.