Single tool with adequate schema but critical gaps in description quality and parameter documentation. Tool name lacks action verb. Description is 156 chars (within range) but lacks WHEN/WHY guidance. Input schema present with types and descriptions, but parameters lack actionable constraints. No output schema documented. No error handling guidance. Fails multiple baseline checks for A/B/C tier tools.

• Rename tool to 'solve_csp_map_coloring' or 'find_map_coloring_solution' to start with action verb and clarify intent.
• Document output schema: 'Returns {"solution": {var_name: value, ...} | null}. Null if unsatisfiable. Example: {"A": "red", "B": "blue"}'.
• Add constraints to 'domains' parameter: 'Dict[str, List[str]]. Keys must match variable names. Values must be non-empty lists of strings (e.g., colors). Required.'
• Add error handling examples: 'If unsatisfiable, returns {"solution": null, "reason": "No valid assignment"}. Try: (1) expand domains, (2) remove constraints, (3) verify edges reference valid variables.'
• Expand tool description to 100-150 chars with WHEN guidance: 'Solves map coloring and general binary CSPs using AC-3 arc consistency + MRV backtracking. Use when you have variables with domains and inequality constraints. Returns assignment or null if unsatisfiable.'