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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is covered. The description adds genuinely useful behavioral context beyond that: the sample is capped at 5 rows and emails/phones are masked, which tells the agent not to expect real contact data. It doesn't mention rate limits or pagination, but for a single-record read that is minor.

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 payload (what you get back) is front-loaded in the first sentence, with the input instruction in a short second sentence. Every clause carries information — field list, price, freshness, sample size, masking — with no 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?

There is no output schema, but the description compensates by enumerating the returned contents and the masking of PII. With one required parameter and complete annotation coverage, an agent has everything needed to call this correctly and interpret the result.

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 coverage is 100% and the single parameter is fully documented in the schema. The description still adds meaning by naming the concrete host (publicleads.com) for the URL form and tying the value back to search_lists output, which the schema only calls 'the list page URL'.

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 (get details) and resource (one list from search_lists), then enumerates exactly what is returned: fields, price, freshness policy, and a masked 5-row sample. It explicitly anchors the input to the sibling search_lists, so an agent can tell it apart from search_lists, get_market_stats, and request_custom_list.

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 second sentence gives a clear invocation path: pass the 'list' value that search_lists returned, or the list's URL. This implicitly establishes the search_lists → get_list_details workflow. It stops short of stating when not to use it (e.g., versus request_custom_list for lists that don't exist), so it earns a 4 rather than a 5.

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