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

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered. The description adds genuinely new context by enumerating the exact metric fields returned and the app/environment scoping rule — valuable since there is no output schema. It does not cover behavior when the campaignId is unknown or not in the given app.

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?

Two sentences, zero filler, with the resource and the returned fields front-loaded before the scoping note. Nothing repeats the title or wastes tokens.

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, enumerating the stat fields in prose is exactly the right compensation, and scope is stated. Gaps remain around not-found behavior and whether campaignId is app-scoped, but for a read-only single-record lookup the description is otherwise sufficient.

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 67%: app and environment are already documented in the schema, and the description merely echoes that the result is scoped by them without adding format or default details. campaignId remains undocumented in both places, though the resource is unambiguous.

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?

States a specific resource (one campaign) and enumerates the statistics returned, which is far more than restating the name. It implicitly contrasts with list_campaigns by specifying a single campaign, but never names that sibling, so differentiation is left to inference.

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?

"Results are scoped to the selected application and environment" implies you must already know the app/environment context, but there is no explicit when-to-use guidance versus list_campaigns (to find the id) or get_analytics_overview / get_breakdown (for cross-campaign aggregates). Usage is implied rather than stated.

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