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

Annotations already provide readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds additional context on top: it is explicitly read-only, 'sends nothing and changes nothing,' scopes to 'this account's leads,' and clarifies that search_leads exposes the same underlying data. The overlap with annotations is acceptable because the extra behavioral context (pagination and scoping) adds value.

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 sentences with no wasted words: purpose first, safety second, alternative third. The tool is easy for an agent to scan and route on quickly.

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?

This is a simple paginated list tool with optional filters, and the annotations already carry the read-only/idempotent profile. The description fully covers the pagination model, the filtering options, and when to switch to search_leads. No output schema exists, but the expected result shape is not needed to invoke the tool correctly.

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 only 50%, so the description needs to compensate. It partially does: 'Page through' conveys the limit/offset pagination model, and 'optionally filtered by campaign and status' maps directly to campaign_id and status. It does not document specific status values, but the schema provides the min/max structure for limit and the example for status.

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 and resource: 'Page through this account's leads', optionally filtered by campaign and status. It also explicitly distinguishes itself from search_leads, so an agent can tell this simple list tool apart from the richer filtering tool without opening the sibling definitions.

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 gives explicit when-to-use versus when-not-to-use guidance: 'For richer filtering (geography, source, tags, contact history, SMS eligibility), use search_leads — the same data with the audience-building filter vocabulary.' This leaves no ambiguity about which sibling to choose.

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