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

Annotations already declare readOnly, idempotent, non-destructive, and openWorld, so the safety profile is covered. The description adds genuine output-level behavior: per-stage conversion rates, an identified biggest drop-off point, and generated recommendations — more than the annotations convey. Minor gap: no statement about what happens with an invalid or unsent campaign_id.

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?

A single front-loaded sentence that moves from the funnel stages to the derived outputs, with no filler. It is slightly dense (three claims in one sentence) but every clause earns its place.

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 one required parameter, no output schema, and annotations already covering safety, the description adequately explains what is returned (stage conversions, drop-off, recommendations). The only missing piece is failure behavior for non-sent campaigns or invalid IDs.

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% for the single campaign_id parameter, and the description only reinforces that the campaign must be a sent one. Baseline 3 applies since the schema already documents the parameter fully; no format or lookup hint is added beyond 'sent campaign'.

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 verb (visualize) and resource (engagement funnel) and enumerates the exact stages: sent → delivered → opened → clicked. It does not differentiate itself from near-sibling analytics tools such as analyze_campaign, campaign_health_dashboard, or compare_campaigns, so an agent must infer the boundary.

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 a sent campaign' implies the prerequisite (the campaign must already have been sent) and scopes usage to post-send analysis. However, it never names an alternative tool or states when to prefer analyze_campaign or campaign_health_dashboard, and no behavior for unsent/draft campaigns is given.

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