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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds context about the diagnostics returned, but does not disclose behavioral details such as required inputs, result shape, or edge cases. It adds some value without contradicting 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 two sentences with no filler: the first states what the tool does and lists diagnostics, the second states when to use it. It is front-loaded and appropriately sized for the tool's role.

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?

Given seven parameters, no output schema, and no parameter descriptions, the description is not complete enough for an agent to call the tool correctly with confidence. It provides a useful high-level purpose but omits required input meaning, optional filter semantics, and output expectations, and it does not clarify how 'expert' differs from 'advanced' or 'basic' insights.

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 description coverage is 0%, so the description must compensate for explaining parameters, but it does not. None of the seven parameters (projectId, startDate, endDate, campaignId, minSendVolume, maxSendVolume, heatmapTimezone) are explained, though the send-time heatmap category loosely hints at heatmapTimezone. This leaves the agent without meaningful parameter 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 uses a specific verb and resource ('Get expert diagnostics') and lists concrete diagnostic categories: campaign fatigue, subject-line keywords, send-time heatmap, monthly trend, audience health. This makes the tool's function clear, but it does not explicitly distinguish it from sibling tools like sm_get_insights_basic or sm_get_insights_advanced.

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 'Use to explain why performance is moving' gives a clear use case for the tool. However, it does not mention when not to use it or suggest alternative sibling tools, so there is no exclusion or comparison guidance.

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