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

Annotations already provide readOnlyHint=true and destructiveHint=false; the description reinforces this with 'Read-only preflight' and 'This tool does not send email or launch the campaign,' then adds detail beyond the annotations about what is actually verified (audience persistence, exclusion semantics, routing, em-dash safety). No contradiction with 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?

Three sentences, each load-bearing: front-loaded purpose and workflow position, then the verification scope, then a single-sentence non-action disclaimer. There is no filler, no restatement of schema field names, and no redundant security boilerplate.

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?

For a tool with 7 simple-typed parameters, 3 required, an output schema present, and full schema parameter documentation, the description covers purpose, workflow timing, verification scope, and safety profile. The only unstated element is how validation failures surface, but the output schema carries the return-structure burden, so nothing essential is missing.

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 100%, and the schema already documents all seven parameters including the exclusion-array semantics. The prose only paraphrases the parameter concepts (expected playlist/contact list, normalized-email exclusions, saved recipient snapshots) without adding syntax or format detail, so the baseline of 3 applies.

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 pairs a specific verb-resource construction ('Read-only preflight for a campaign draft') with an exact workflow position ('before using DropTrack Send Test'). It further disambiguates by enumerating the verification scope (draft state, audience persistence, subject, signoff, Reply-To/test-recipient routing, em-dash safety) and explicitly negating sending/launching, so an agent can distinguish it from retrieval, creation, and send siblings.

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 gives explicit when-to-use context, placing the tool as a preflight immediately before DropTrack Send Test, and states the operational prerequisites (expected playlist and contact list). It does not explicitly name alternative validation or read-only siblings (e.g., droptrack_get_campaign_details) or give when-not-to-use exclusions, so it stops short of full alternative routing.

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