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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds genuine behavioral value beyond that: it enumerates the return contents (monthly/hourly compute estimate, pricing coverage, per-namespace/stack breakdown) and discloses the important limitation that costs are compute-only list-price estimates, not the customer's actual bill.

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 tightly written sentences: purpose first, then return contents, then the critical estimation caveat. Every sentence carries distinct information with no repetition or 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?

There is no output schema, and the description compensates by describing the return payload and its limitations. For a read-only, single-parameter tool with full schema description coverage and clear annotations, the definition is sufficient to call correctly.

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 a single parameter whose description already explains it is an Ankra cluster UUID discoverable via list_clusters. The description adds no additional parameter meaning, so the baseline of 3 applies.

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 clear scope: 'Get the estimated cloud infrastructure cost for the current cluster.' However, it does not differentiate itself from cost siblings such as get_stack_cost, get_fleet_cloud_cost, get_object_cost, or get_namespace_cost_history, so an agent must infer which cost tool to pick.

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?

Usage is implied (fetch cluster-level compute cost estimates) but there is no explicit when-to-use guidance, no exclusions, and no named alternative among the many cost-related siblings. The caveat about estimates vs. actual bill is useful context but does not route the agent.

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