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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds a useful list of returned counters but does not disclose return format, aggregation period, or any other behavioral details. No contradiction with annotations exists.

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, efficient sentence that front-loads the core scope and lists the returned metrics without any wasted words. Every part contributes to understanding the tool's behavior.

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?

For a simple one-parameter, read-only tool with strong annotations and no output schema, the description is nearly sufficient. The main gap is failing to differentiate from get_campaign_analytics and not stating any time-range or scope limitations, but the core calling information is present.

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 coverage is 100% because campaign_id is described as 'Campaign id'. The description does not add meaningful new meaning beyond the schema, only reinforcing that the tool targets one campaign, which fits the baseline 3 for a fully documented parameter.

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 what the tool returns: delivery and engagement counters for one campaign, specifically sent, failed, opens, clicks, and replies. However, it does not distinguish itself from the sibling get_campaign_analytics, which could cause an agent to be unsure which analytics tool to choose.

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 phrase 'for one campaign' implies use when the agent needs per-campaign counters, which is a clear usage context. But there is no explicit guidance about when not to use it or which sibling alternative (e.g., get_campaign_analytics) to prefer, leaving the choice partially to inference.

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