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

Annotations already declare readOnlyHint true and destructiveHint false, so the description only adds the list of included metrics, which is useful but not extensive. It does not disclose return format, time ranges, or aggregation behavior, so it adds some context but falls short of rich behavioral detail.

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 sentence, front-loaded with the main idea, and includes a compact list of metrics. Every word contributes value; there is no fluff or repetition.

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?

While the description is clear about the purpose and metrics, the lack of parameter guidance and absence of an output schema leave gaps. The agent may not know how to specify the campaign or what the exact return structure is, though the listed metrics provide a partial picture.

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 schema has two parameters (campaign_id, campaign_name) with zero description coverage, and the tool description does not mention them at all. There is no explanation of how to identify the campaign, whether either/both parameters are needed, or their expected formats, leaving the agent without necessary guidance.

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 'Get' and the resource 'performance stats for a specific campaign', listing specific metrics (opens, clicks, replies, bounce rate). It distinguishes from sibling tools like get_dashboard_stats and get_bounce_stats by specifying campaign-level detail.

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?

Usage is implied rather than explicit: the description indicates this is for a specific campaign's stats, but it does not state when to use it over alternatives or include any exclusions. Sibling tool names provide contextual differentiation, but the description itself offers no direct guidance.

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