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

Annotations already declare readOnlyHint=true and idempotentHint=true, but the description adds substantial behavioral context: newest-first ordering, pagination via 'compare returned against total', the existence of empty campaigns ('leadsTotal 0'), and the caveat about generic titles. None of this contradicts the annotations; it enriches the agent's understanding of edge cases and data quality.

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 long but every sentence carries actionable information: purpose, sorting, pagination, entry fields, sibling routing, and data caveats. It is front-loaded with the main function and sort order, then structured logically. No redundancy or 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?

Given the tool's simplicity (one optional parameter) and the presence of an output schema, the description covers all necessary aspects: purpose, usage context, data fields, sibling tool routing, pagination, and data-quality warnings. 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?

The schema covers 100% of parameters (only 'limit'), and the description adds beyond it: default value 50, interpretation via 'returned against total', and the implication that older campaigns may be omitted. This clarifies how to use the parameter and what the response means, going beyond the schema's basic description.

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 verb ('list') and resource ('campaigns (past lead searches)') with a clear scope: 'in this workspace that the user takes part in'. It differentiates from siblings by naming what each alternative does and when to use them (e.g., 'list_next_steps ... is the answer when the user asks for recommendations rather than numbers').

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?

Explicitly says when to use: 'Use it to see which ICP cohorts have already been tried before proposing a new one.' It also lists sibling tools and the conditions for choosing them ('Pass an id to get_campaign for its ICP, ... list_next_steps for what the campaign still needs a human to do'). This gives clear when-to and when-not-to guidance.

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