get_deployment_cost

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

Annotations already mark the operation read-only and idempotent, and the description adds meaningful behavioral context: admin API key requirement, failure mode for unknown deployment_id ('not_found'), and the fact that costs include billing markup. These details go beyond the structured annotations and accurately specify observable behavior.

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?

The description is dense but every sentence contributes: return fields, authentication, error behavior, and routing to related tools. The trailing 'Read-only.' is redundant with annotations but harmless; overall the structure is front-loaded and efficient.

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 simple one-parameter tool with no output schema, the description covers return fields, auth requirements, error semantics, and related sibling tools. It does not detail response formatting, but the listed fields and existing annotations are sufficient for correct invocation in most cases.

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?

The input schema already describes deployment_id as coming from get_deployment, so the schema carries most of the burden. The description adds clarity by defining the id as referring to a single deployment and instructing the agent to get the active deployment first, which enriches the parameter meaning without contradicting 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?

The description states a specific verb ('Get'), the exact resource ('current-month cost details of one deployment by id'), and enumerates the fields returned. It is clearly distinguishable from siblings like get_billing_info and get_deployment because it names per-deployment cost and the required id.

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 explicitly says when to use the tool ('to find the active deployment first' with get_deployment) and identifies an alternative for a different concern ('get_billing_info for the organization's plan and subscription state'). It also includes a precondition: an admin API key is required.

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