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

The annotation set already marks this as read-write, idempotent, and non-destructive. The description adds a genuinely useful behavioral guarantee: only provided fields are updated, so missing fields are not overwritten. This goes beyond the structured 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 short sentences, no filler. The main action is front-loaded, the partial-update caveat follows immediately, and the lookup guidance is at the end.

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 simple partial-update tool, the description covers what the tool does, how it treats missing fields, and how to obtain the required leadId. The only minor gap is that it does not specify whether a provided tags array replaces or merges with existing tags, but the schema's maxItems constraint and 'only provided fields are updated' wording keep this sufficient.

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?

With only 25% schema description coverage, the description compensates by naming the two content parameters (notes and tags) and clarifying that they are optional in effect ('Only provided fields are updated'). The leadId purpose is implied via the lookup instruction, and workspaceId is described in the schema.

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 states a specific action ('Update') on a clear resource ('user-level metadata (notes and tags) on a lead'), which distinguishes it from sibling tools like update_lead_contact_info. The parenthetical enumerates exactly which fields are affected.

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?

It gives a concrete prerequisite: use campaignstack_search_leads or campaignstack_get_lead to obtain lead IDs. It does not explicitly contrast with alternative update tools, but the field scope makes the intended use clear.

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