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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is clear. The description adds value by indicating the tool returns subscription tier, limits, and usage, which gives a clue about the response contents. However, it does not disclose any other behavioral traits such as error conditions or auth requirements.

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 a single, tightly written sentence that front-loads the action ('Get') and is free of filler. It conveys the core purpose efficiently without wasting words.

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 very simple, zero-parameter read-only tool, this description is largely sufficient. It names the key returned aspects (tier, limits, usage). There is no output schema, so a bit more detail on the structure of these fields could have been helpful, but the low complexity keeps the description reasonably complete.

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 tool has zero parameters, and the schema coverage is 100% (trivially, since no parameters exist). The description does not need to elaborate on parameter meanings, and no additional semantics are required. The baseline for zero-parameter tools is 4.

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 clearly states the verb 'Get' and the specific resource 'subscription status' with the details 'tier, limits, and usage'. This unambiguously distinguishes it from sibling getters like get_project or get_user_info, which target different resources.

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 provides no explicit context on when to use this tool versus alternatives, nor does it mention exclusions or prerequisites. It simply states what it does, leaving the agent to infer usage from the tool name and sibling context.

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