Listing statistics

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

Annotations already provide readOnlyHint=true, etc. The description adds behavioral context: limits (200 items, 270 days) and read-only nature. No contradiction with annotations.

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?

Three sentences with no fluff. First sentence states main purpose, second gives usage guidance with alternatives, third states limits. Front-loaded and efficient.

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 hints at the return structure (counters grouped by period) and lists the metrics. It covers usage and constraints well. Could be slightly improved by explicitly mentioning the response includes item IDs and periods, but overall complete enough.

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% with detailed param descriptions. The description adds minimal extra value beyond what schema already provides, such as clarifying that counters are 'shallow statistics' and listing the metric types. According to guidelines, baseline is 3 when coverage is high.

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?

The description clearly states the verb 'Returns counters' and the resource 'listings over a period', specifying the exact counters (unique views, contacts, favorites). It distinguishes from siblings by mentioning alternatives for extended analytics and calls.

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 says when to use this tool (metrics on specific item_ids grouped by day/week/month) and when not to use (extended analytics use items_post_item_analytics, calls use items_post_calls_stats). Also includes limits on listings and time depth.

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