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

The readOnly and idempotent annotations already cover the non-destructive nature, and the description reinforces a pure summarization behavior. It additionally clarifies the scope ('one website') and the kind of data included, which goes slightly beyond the 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?

The description is a single, compact sentence with no redundant phrases. It front-loads the core purpose and then efficiently lists the included metrics, making it easy to scan.

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?

With no output schema, the description compensates by naming the principal metrics returned. It does not specify grouping, timezone handling, or exact formatting, but for a summary analytics tool the enumerated metrics provide adequate context for most agents.

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?

The input schema already provides full descriptions for both parameters, including defaults and source for website_id. The description adds contextual alignment by mentioning 'over a period' and 'one website', but it does not need to repeat parameter details since schema coverage is complete.

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 a specific action ('Summarise') and resource ('one website's chat activity over a period'), and enumerates the concrete metrics returned: conversations, messages, leads, escalations, and visitor countries. This distinguishes it from sibling tools that operate on raw conversations, leads, or daily reports.

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?

The description implies usage when an aggregate summary of chat activity is needed, and the period parameter is referenced. However, it does not explicitly contrast with alternatives like get_daily_report or list_conversations, leaving some ambiguity about when to prefer this tool.

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