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

With no annotations, the description must carry the behavioral burden; it implies a read-only listing and gives a dedupe motivation, which is useful. But it never states result limits, pagination, ordering, or what happens when the list is large — material gaps for a listing tool with zero annotation coverage.

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 tight sentences, zero filler, with the action and the motivating workflow constraint front-loaded.

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?

For a one-optional-param read tool with no output schema and no annotations, the definition covers purpose, trigger condition, and the one parameter via schema. The only meaningful omission is return behavior such as result caps or whether the full client list is returned.

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 `query` parameter is fully documented as an optional substring match on name or email. The description adds no extra semantics beyond that, so the baseline 3 applies.

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 existing clients"), immediately distinguishing it from the sibling write tool create_client. It doesn't mention the other list sibling (list_invoices), but the resource noun makes the split obvious.

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 says to call this before create_client to avoid duplicate customer records, which names the alternative and the ordering condition. It stops short of saying when not to use it (e.g., when a client ID is already known), so not a full 5.

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