get_billing_info

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint true and destructiveHint false, covering the safety profile. The description adds the fact that it returns both the account and its status and that environment inspection is parameterized, but it does not disclose potential error cases, auth requirements, or what 'status' means. This is acceptable because annotations carry the main behavioral burden.

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 efficient sentences with the core purpose first and parameter documentation second. No filler, no repetition of annotation fields, and all content earns its place.

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 one-parameter, read-only tool with rich annotations and no output schema, the description is nearly complete: it states purpose, return subject, and parameter usage. It does not specify possible status values or behavior when no billing account exists, but these are minor gaps for an optional-parameter read tool.

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?

Despite 0% schema description coverage, the description fully explains the sole parameter: what environment represents, examples ('staging', 'production'), and the default behavior when omitted. This is more than the schema provides and leaves no ambiguity about how to invoke the tool.

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 object: 'Return the billing account linked to the project and its status.' This clearly conveys functionality and, by focusing on billing account rather than costs or logs, distinguishes it from siblings like get_cost_breakdown and query_logs. However, it does not explicitly name a sibling or draw a contrast, so it stops short of a 5.

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?

Provides no when-to-use guidance or exclusions relative to sibling tools. The only usage instruction concerns the optional environment parameter ('Omit to use the default environment'), which is parameter behavior, not tool-selection guidance. An agent must infer from the name and purpose when this tool is appropriate.

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