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

Annotations cover the safety profile (readOnly=false, destructive=true, openWorld=false), so the bar is lower, and the description still adds substantive behavior: project linkage, propagation of currency and hourly rate to the client's time, and a plan-limit constraint. It doesn't state whether the operation is reversible or what happens when the free-plan limit is hit, so it falls short of a 5.

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 short sentences, front-loaded with the core action, then useful domain context, then the quota caveat. No filler, though the linkage sentence and the rate sentence could be merged without loss.

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 an 8-parameter mutation tool with no output schema, the description covers the domain model and a quota constraint but omits what a successful call returns (e.g., the new client identifier) and whether any parameters are required. It is adequate but leaves meaningful gaps for an agent composing the call.

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 63%, so roughly a third of the 8 parameters (notes, phone, address, and partially others) carry no documentation anywhere. The description adds domain meaning for currency and hourlyRate by explaining how they propagate to projects and time, but leaves the remaining parameters to the schema. Baseline 3 is appropriate.

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?

"Adds a client" is a specific verb+resource, and the following sentences clarify what a client is in this domain (linked to projects, carries currency and hourly rate). It doesn't explicitly distinguish itself from siblings like update_client or archive_client, but the resource naming is unambiguous enough for selection.

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 description gives a real precondition — the free plan allows only 2 active clients — which tells the agent when this call may fail or be inappropriate. However, it names no alternative (update_client, restore_client) and states no when-to-use vs. when-not-to-use rules beyond the quota.

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