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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds the HTTP route and the returned field set, but says nothing about pagination behavior, result caps, or ordering defaults beyond what the schema documents — useful but modest added 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?

A single front-loaded sentence with the key scope first, the return fields parenthetically, and the endpoint last. No wasted text; the trailing 'GET /contacts?list_id=...' is slightly truncated but harmless.

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?

With 6 parameters, 100% schema coverage, and no output schema, the description does the one thing it must — enumerate the returned fields (id, email, name, added by, subscription date) — while annotations and schema cover safety and paging. Complete enough to invoke 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 100% with clear enum documentation for status, order, and order_by, so the schema does the heavy lifting. The description only restates the optional state filter, adding no format or semantics beyond the schema — baseline 3.

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 (list contacts) with a clear scope constraint ('of one list') and enumerates the returned fields, which separates it from emailchef_get_contact and emailchef_list_blocked. It stops short of naming a sibling alternative explicitly, so it is clear but not maximally differentiated.

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?

'Of one list ... optionally by state' implies when the tool is appropriate and the state-filter option, but there is no explicit when-to-use vs. when-to-use-something-else guidance (e.g., get_contact for a single record, get_list_stats for aggregates). Usage must be inferred.

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