google_ads_device_analyze

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so description carries full burden. It declares the tool is read-only. Describes return structure including edge cases: 'cpa is None when conversions == 0', insights fire under conditions like 'spend and zero conversions, worst/best CPA ratios > 1.5x, and Mobile CTR less than half of Desktop CTR', and returns 'message' field with empty devices list when no device-segmented data exists. No contradictions.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Description is a single dense paragraph covering purpose, return structure, edge cases, usage guidelines, and sibling differentiation. It is efficient and front-loaded with the core purpose. Could be improved with bullet points for readability, but no wasted sentences.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given no output schema, the description thoroughly explains the return structure, edge cases (cpa None, empty devices, insight triggers), and provides usage guidance. Covers all necessary context for an AI agent to use it correctly alongside sibling tools.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so baseline is 3. Description adds context for the period parameter by advising on window selection based on use case (recent changes vs trends). Does not repeat schema's fallback behavior for customer_id but adds value beyond schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Clearly states the tool compares Google Ads campaign performance across device segments (Desktop/Mobile/Tablet) and specifies return structure. Distinguishes from sibling tools like google_ads_bid_adjustments_update and google_ads_device_targeting_set by noting they modify bid adjustments or targeting, not analyze performance. Also differentiates from google_ads_schedule_targeting_list for hour-of-day targeting.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly states when to use: for comparing device performance, and provides alternatives: 'For applying device bid modifiers use google_ads_bid_adjustments_update or google_ads_device_targeting_set; for the raw ad-schedule criteria use google_ads_schedule_targeting_list.' Also gives guidance on period parameter: 'Use a shorter window (LAST_7_DAYS / LAST_14_DAYS) when diagnosing recent changes; use LAST_90_DAYS for trend baselines.'

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.