Estimate the cost of a job before starting it

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, so the safe-read profile is covered. The description adds a billing-specific reassurance ('without ... charging anything'), which is useful but largely reinforces what the annotations say; it says nothing about estimate staleness, currency, or permissions.

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 padding, with the core guarantee (no start, no charge) front-loaded before the usage conditions.

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?

Covers the safety and usage profile well for a 3-param tool. With no output schema, the description could have stated the shape of the returned cost (units/currency), which is a minor remaining gap.

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 each parameter documented (source enum, total_records range/multiple, email_verification boolean), so the baseline of 3 applies. The description adds no parameter-level detail beyond what the schema provides.

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: 'Return what a job would cost without starting it or charging anything.' The scope negation ('without starting it') implicitly separates it from the sibling job-execution tools, though no sibling is named.

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 two concrete conditions for use: 'before spending on behalf of someone' and 'when the user asks how much a list will cost.' Clear triggering context, but no explicit exclusions or named alternatives (e.g., versus job_status or check_balance).

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