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

Goes well beyond the annotations (readOnlyHint=false, destructiveHint=true): it explains that each actual change is written to the lead's timeline, that the assignee receives one aggregated in-app notification plus at most one email per batch depending on their preferences, and that re-assigning the same owner is a no-op for notifications. This clarifies the practical meaning of the 'destructive' hint (clearing an assignee) and discloses side effects the agent could not otherwise anticipate.

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?

Front-loaded with the action and its two modes, followed by batch constraint, validation, and notification consequences in descending order of importance. Dense but every sentence carries operational information; the notification sentence is the longest and only marginally relevant to selection, costing a point.

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 small two-parameter mutation tool with annotations and an output schema, the description covers scope, batching, validation, idempotency, and side effects. The remaining gap is failure behavior: it does not say what happens with invalid or foreign-team lead ids, or whether partial assignments succeed, which matters for a destructive batch write.

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%, with leadIds (maxItems 50) and assigneeId ('me'/null) already documented in the schema, so the description mostly restates those semantics. It does add one piece of meaning beyond the schema: the assignee must be an active member, with list_lead_settings.assignableMembers given as the validation source. That extra constraint is useful but narrow, so the 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 with scope: 'Assign one or more leads of the current team to a member, or clear the assignee.' Both the batch-assign and unassign modes are named up front, and no sibling tool overlaps this operation, so an agent can identify it immediately.

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?

Gives strong operational guidance: batch all lead ids into one call (up to 50) rather than looping, the assignee must be an active member with a pointer to list_lead_settings.assignableMembers, 'me' means self, and omit/null clears the assignee. It doesn't name a competing tool to use instead, but no sibling performs assignment, so there is little alternative-selection ambiguity left.

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