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 known without the description. The description adds the non-obvious fact that it returns a letter grade and actionable recommendations, but it does not disclose any additional behavioral traits (e.g., required auth, rate limits, or latency). It adds some context but stays within the annotation coverage.

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, front-loaded sentence that states the purpose first and then enumerates outputs. It contains no redundant phrases or obviously wasted terms. Every clause contributes to the agent's understanding of what the tool does and what it delivers.

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?

Without an output schema, the description appropriately explains the return content (grade, scores, deliverability, insights, recommendations). It does not mention error conditions, pagination, or the reliance on api_key, but the api_key is present in the schema and the operation is a safe read, so a competent agent can infer authentication needs. This is slightly incomplete but sufficient for a single-campaign analysis tool.

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 covers 100% of parameters with descriptions, so it already documents api_key, campaign_id, and cost_per_email. The description does not add any parameter-specific meaning beyond the schema, and the mention of 'cost per email in dollars' is already present in the schema. No extra semantic depth is provided, so a baseline 3 is appropriate.

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 ('Deep-dive analysis') and the resource ('a single campaign'), and enumerates a specific list of outputs (letter grade, performance scores, deliverability health, insights, recommendations). It explicitly scopes to 'single campaign', which distinguishes it from sibling tools like analyze_latest_campaigns (plural) and audit_campaign_draft.

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 description implies usage for analyzing one campaign's performance but does not explicitly say when not to use it or mention any alternative tools. While 'single campaign' sets a clear context, it lacks an explicit routing statement such as '0use this instead of analyze_latest_campaigns' or 'when you have a specific campaign, not a list'.

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