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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds that engagement and last open/click data are returned, which is useful context absent an output schema, but says nothing about pagination behavior or result limits.

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 tight sentences: the primary purpose and returned data are front-loaded, and the sibling routing hint follows. Every clause carries information; no filler.

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 7 parameters but 86% schema coverage and no output schema, the description does enough by naming the returned status/engagement fields and pointing to get_lead for detail. It could still mention pagination or result-size expectations, but the essential calling information is present.

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 86%, and the schema documents tags, limit, cursor, search, status and engagement thoroughly. The description only alludes to status/engagement as returned fields, adding no filtering syntax or semantics beyond what the schema already provides, so baseline 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?

States a specific verb and resource (list leads of a campaign) plus the scope of returned data (status and engagement: emails opened/clicked, last open/click). It explicitly differentiates itself from get_lead, so an agent can pick between the list and the detail tool without reading schemas.

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?

Provides a clear routing rule: use this for listing leads with status/engagement, use get_lead for a lead's progress through the sequence. It gives no exclusions or edge-case guidance (e.g., very large campaigns, when to prefer filtering), but the alternative is named explicitly.

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