Four tools with basic schemas and descriptions, but significant gaps in parameter documentation and output schema clarity. All tools are READ_ONLY file operations on .pen files. Naming follows verb_noun pattern (pencil_*) but descriptions are terse (avg 65 chars, below 194-char baseline). No parameter descriptions visible in schema definitions. Output schemas not documented. Error handling minimal, no recovery guidance or actionable error messages. Tool composition is reasonable (each does one thing), but parameter constraints and validation rules are absent.

• Add detailed parameter descriptions to all tools. E.g., 'path (string): Absolute or relative path to a .pen file (ZIP or JSON). Supports ~ expansion. Required.'
• Document output schemas for each tool. E.g., pencil_extract_tokens returns {colors: [{name, hex, usage_count}], fonts: [{name, weight, size}], spacing: [{name, value}], variables: [...]}, or similar.
• Enhance error messages with recovery hints. E.g., 'File not found: /path/to/file. Ensure the path is correct or call pencil_list_files() to discover available .pen files.'
• Add constraints to numeric parameters. E.g., max_depth: integer, minimum 1, maximum 20, default 5.
• Implement per-item error reporting in pencil_batch_validate. Return {results: [{path, valid: bool, errors: [string]}]} so agents can identify and retry only failed files.