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

Annotations already declare readOnlyHint=true, idempotentHint=true and openWorldHint=false, so the safety profile is fully covered. The description adds no behavior beyond that — nothing about what the trial status represents, whether it is scoped to the caller's account, or what happens if there is no trial.

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?

There is no waste in length, but the content is a duplicated path string rather than informative prose; the second copy of the sentence earns nothing.

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 tool with no output schema and two undocumented parameters, the description should explain what the endpoint returns and what the query object accepts. Instead it defers entirely to describe_operation, leaving the agent without enough to call it confidently.

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 0% and the description says nothing about the two parameters. The free-form 'query' object (additionalProperties: {}) is entirely undocumented anywhere, so an agent has no idea what query keys are accepted.

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 is the raw path 'GET /api/subscription/trial-status' repeated twice, which restates the name/title rather than explaining in plain language what trial status is returned (trial expiry, eligibility, days remaining?). It never distinguishes this from siblings like get_subscription_status or get_subscription_billing_check.

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 when-to-use guidance, no prerequisites, no alternatives. The only sentence beyond the path, 'describe_operation provides native request schemas,' is a pointer to another tool, not a usage rule.

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