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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavior: newest-first ordering, default 20-per-page, and that email filtering yields at most one lead. It doesn't explain pagination termination or whether a total count is exposed, leaving a gap for a list tool.

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, no filler: what it does and ordering first, then the two filter modes, then the practical use case. Well front-loaded and every sentence earns its place.

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?

Adequate for a four-parameter, zero-required list tool with full schema coverage and safety annotations, with no output schema requiring return-value explanation. The only implicit piece is pagination behavior, such as how to know when results are exhausted.

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 100%, so page, limit, email, and campaignId are already documented. The description reinforces email semantics (at most one result) and restates the 20-per-page default, but adds nothing about how page and limit interact — baseline 3 applies when the schema does the heavy lifting.

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 ("Lists the leads in the workspace") plus ordering and page size, and names the concrete end goal (finding the ID of a lead you added earlier). An agent can distinguish this from list_campaigns and add_leads by resource alone.

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 concrete conditions: exact-email filter to look up a single lead, campaign filter to list one campaign's leads, and using it to recover a lead ID. It stops short of explicit when-not guidance or naming an alternative sibling, so it's clear context rather than full routing.

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