Estimate credits for a run

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

Beyond the readOnlyHint/openWorldHint annotations it discloses the cost model ('1 credit = 1 profile scanned'), that nothing is spent, that no API key is required, and that the response reports the cap it assumed. These are exactly the behavioral facts an agent needs and none of them live in the annotations.

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 tight sentences, front-loaded with the core guarantee (no spend) followed by the parameter relationship and the auth note. No filler.

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 side-effect profile, auth requirement, and output shape (min/max plus assumed cap) despite there being no output schema. It leaves open how the estimate relates to actual spend or how slug defaults affect the number.

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?

Top-level schema coverage is 0% for slug and input, so the description has to compensate. It usefully explains that the input matches launch_discovery and that creditsCap is optional (with the assumed cap echoed back), but it says nothing about the slug playbook enum or which nested fields matter for a specific playbook.

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+resource (estimate a run's credit cost) and scopes the output (min/max) while naming the sibling it contrasts with (launch_discovery). An agent can distinguish it from every other sibling without opening the 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 clear context: use it when you want cost information 'without launching or spending anything,' and it names launch_discovery as the input-compatible alternative. No explicit when-not or prerequisite ordering (e.g. 'call before launch_discovery') is stated, so it stops short of a 5.

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