Cobrain defines 6 tools with explicit Zod schemas and descriptions. All tools have names starting with action verbs (read_, archive_, consolidate_, update_, log_, send_). Descriptions are present and reasonably detailed (avg ~120 chars). However, several parameters lack descriptions or have minimal guidance. Error handling uses helper functions (toolError/toolSuccess) but responses are generic text without recovery guidance. No output schemas documented. Parameter constraints are minimal, dates accept strings without format validation, arrays lack length bounds. Tool composition is reasonable (single responsibility), but some tools like archive_events and consolidate_event could benefit from clearer preconditions and side-effect documentation.

• Add explicit output schemas to all tools. E.g., read_memory_files should return {facts: string, events: string, lastUpdated: ISO8601} instead of generic text.
• Enhance error responses with classification and recovery hints. Replace toolError('Read error', error) with {isError: true, errorType: 'retryable'|'user_fixable'|'fatal', message: '...', suggestion: 'Try calling X with Y'}.
• Add format validation to date parameters: z.string().regex(/^\d{4}-\d{2}-\d{2}$/).describe('Date in YYYY-MM-DD format'). Add .min(1).max(100) to dates array in archive_events.
• Document idempotency and side effects in tool descriptions. E.g., 'archive_events: Idempotent. Calling twice with same dates is safe; second call returns 0 archived.'
• Add length constraints to text parameters. E.g., send_report text: z.string().max(4096).describe('Report text (max 4096 chars for Telegram compatibility)').