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

Annotations indicate readOnlyHint=false and destructiveHint=true, but the description adds valuable behavioral context: 'Each actual change is recorded on the lead's timeline' and describes the aggregated notification and email behavior, including that reassigning the same owner does not trigger another notification. This goes beyond the annotations and helps the agent understand side effects and user-facing impacts.

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 somewhat long but every sentence provides useful guidance: purpose, batching rule, assignee requirements, unassign method, and side effects. It is front-loaded with the core action and then provides necessary operational details. It is not overly verbose given the amount of information needed for correct usage.

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 mutation tool with an output schema and two parameters, the description covers all essential aspects: what to pass, how to batch, who qualifies as assignee, how to unassign, and what side effects occur (timeline recording, notifications). It also points to a sibling for eligible assignees. Nothing an agent needs to call it correctly 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 coverage is 100% and both parameters already have detailed descriptions (e.g., 'The member userId to assign to, or "me"... Omit (or pass null) to clear the assignee.'). The description repeats these details but adds no new parameter-specific information beyond the schema. The batching instruction (up to 50) is also already in the schema's maxItems. Therefore, the description adds minimal extra parameter meaning.

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 action: 'Assign one or more leads of the current team to a member, or clear the assignee.' This is a specific verb (assign) with a specific resource (leads) and an additional action (clear). It distinguishes itself from siblings like set_lead_tags or update_lead by focusing on the assignment/ownership change.

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 provides explicit usage rules: 'Pass every lead id in a single call (up to 50) — do not loop one call per lead.' It also specifies prerequisites (assignee must be an active non-viewer member, see list_lead_settings.assignableMembers) and explains how to unassign (omit/null). It does not explicitly name alternative tools for the same operation, but it points to a sibling for prerequisite info, and the 'do not loop' instruction is a clear when-not-to-do.

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