Three read-only tools with clear, domain-specific descriptions (avg 180 chars). All tools have explicit input schemas with type definitions. However, parameter descriptions are minimal or absent: 'date' and 'weeks_ahead' lack constraint documentation (format, range). No output schema is documented, LLMs cannot predict response structure. Error handling converts SisrunError to RuntimeError without recovery guidance. No tool annotations (readOnlyHint present semantically but not declared).

• Add parameter descriptions to schema: 'date' → 'ISO 8601 date (YYYY-MM-DD) for the week to fetch. Navigating far from current week costs one request per week hop.' 'weeks_ahead' → 'Number of weeks ahead to fetch (0 - 8, default 1). Larger values cost more requests.'
• Document output schema in tool descriptions. E.g., 'Returns JSON with keys: week_start (ISO date or null), workouts (array of {date, status, modality, planned_km, ...}), warning (optional string if detail panels missing).'
• Enhance error messages with recovery hints. E.g., catch ValueError for invalid date and return 'Invalid date format. Use YYYY-MM-DD (e.g., 2024-01-15).' Catch SisrunError and suggest 'Check credentials in ~/.sisrun/credentials or SISRUN_EMAIL/SISRUN_PASSWORD env vars.'
• Add tool annotations to server.py: @mcp.tool(readOnlyHint=True, idempotentHint=True) for all three tools to signal to clients that they are safe to call repeatedly.
• Move credential loading to server initialization with explicit error if missing, rather than lazy loading in _get_client(). Log credential source (env var vs file) for audit trails without exposing secrets.