14 tools with mixed quality. Naming is strong (verb-first, clear intent). Descriptions are present and detailed (100-200 chars typical), exceeding baseline. Schemas are well-structured with enums and constraints visible in code. However, critical gaps: (1) draw_path has no items schema for points array, LLM cannot infer point structure; (2) draw_rect, draw_line, draw_arc, draw_text lack minItems/maxItems on color params; (3) no output schemas documented for any tool; (4) no error handling guidance (e.g., what if ADC read fails? what if I2C scan times out?); (5) no idempotency hints on write operations. GPIO tools are stronger than display tools. Overall: solid naming and descriptions, but incomplete schemas and missing error recovery patterns.

• Document output schema for every tool. For i2c_scan, specify: returns {addresses: [int]} or {devices: [{address: int, name?: string}]}. For read_pins, specify: {values: {[gpio: int]: int}} or array of {gpio, value}.
• Add items schema to draw_path.points: {type: 'array', items: {type: 'object', properties: {x: {type: 'integer', minimum: 0, maximum: 171}, y: {type: 'integer', minimum: 0, maximum: 319}}, required: ['x', 'y']}}.
• Add error handling to descriptions. E.g., configure_pins: 'Returns error if gpio not in safe list or mode=ADC on non-ADC pin. Call get_gpio_capabilities first to verify.' i2c_scan: 'Returns empty array if no devices found or timeout after 1s.'
• Add idempotency hints to write tools. E.g., write_digital_pins: 'Idempotent, calling twice with same pins/levels has same effect as once.' set_pwm_duty: 'Idempotent, safe to retry.'
• Constrain color parameters in schema, not just description. Add minimum: 0, maximum: 255 to r, g, b properties in draw_rect, draw_line, draw_arc, draw_text.