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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=true, destructiveHint=false), and the description adds genuinely new context: per-item credit cost, the four item outcomes, and the caveat that 'clear' is not a certification. It also documents idempotent replay behavior with its 409/422 failure modes, which the annotations say nothing about. That is solid added value, though it stops short of describing result volume or ordering.

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?

Front-loaded with the core action and the hard cap, then the gating requirement and cost, then the semantics. It is dense with no filler, but the per-item status explanation and idempotency clause make it longer than a single-scan read; a slightly tighter grouping would help.

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, so the description carries the return-value burden and does so by enumerating all four per-item statuses and warning about the false reassurance of 'clear'. Combined with auth scope, cost, and idempotency semantics, an agent has everything needed to call it 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%, so the baseline is 3, but the description earns an extra point by tying 'threshold' to what 'clear' actually means and by spelling out the idempotency_key replay contract with concrete 409 (still running) versus 422 (items differ) outcomes. The remaining parameters (list, group, limit, active_only) are left entirely to the schema.

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 with explicit scope: 'Screen up to 50 names against the sanctions lists in ONE call' plus the endpoint. The batch framing plus the 50-name cap lets an agent distinguish it from the single-name sibling sanctions_screen without opening either schema.

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?

Gives real preconditions: the sanctions scope is required, batch calls do not draw on the free trial allowance, and each item costs 3 credits. It implies but never explicitly names sanctions_screen as the alternative for single-name screening, so the routing guidance stops just short of fully explicit.

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