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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered structurally. The description adds genuinely new behavioral context beyond them: the shape of the returned data and the fact that rules are rendered as human-readable prose rather than raw criteria. It does not mention whether all lists are returned or any ordering/limits, which keeps it at 4.

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?

Two sentences, front-loaded with the resource and its returned fields, then the routing information. Every clause earns its place by either defining the resource or naming an alternative tool, and the illustrative rule example does real work in clarifying the vague phrase "rules in words".

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?

Because there is no output schema, the description bears the burden of explaining return values, and it does so adequately by naming the id and name fields plus the rules summary. It's complete for a simple zero-parameter read tool, with minor gaps around ordering, volume, and whether lists are paginated.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The description correctly signals that no arguments are needed by describing the listing as workspace-wide.

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 ("The workspace's saved lead lists") and immediately enumerates what comes back: id, name, and rules in words. The parenthetical example of a rule ("Interested, Eastern time, not called in 7 days") makes the resource concrete and distinguishes it from lead-returning siblings.

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 routes the agent forward: read the leads on a list with list_leads_in_list, or pass list_id to search_leads to search within it. That covers the main follow-on decisions clearly. What's missing is a direct when-to-use framing (discovery step before any lead query) and any when-not condition, so it stops just short of full guidance.

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