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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the agent knows it's a safe read. The description adds no extra behavioral context (e.g., what 'extended' includes, any auth requirements). It doesn't contradict annotations, but it also doesn't enrich them beyond the minimal claim.

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 brief and front-loaded, but the second sentence ('Gets extended information about the users subscription') essentially repeats the first, adding redundancy without new content. A single sentence would have been sufficient.

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?

Given the minimal description, no output schema, and a single undocumented optional parameter, the tool's behavior is underspecified. It doesn't explain what 'extended information' includes, how to query a specific account, or what the response might contain. This is inadequate even for a simple getter.

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?

There is one optional parameter 'account' with 0% schema description coverage, and the description doesn't explain its meaning or how it affects the result. The description entirely fails to compensate for the schema gap, leaving the parameter's semantics completely unspecified.

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 'Get User Subscription Info' with a verb and resource, indicating it retrieves subscription details. It adds 'extended information' to differentiate from simpler user info, but it doesn't explicitly contrast with siblings like elevenlabs_get_user_info, so it's clear but not fully distinguishing.

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?

No mention of when to use this tool versus alternatives. The sibling list includes elevenlabs_get_user_info and other get_* tools, but the description provides no context on selecting this one. No exclusions or prerequisites are given.

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