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

With no annotations, the description carries the full behavioral burden. It usefully discloses that an admin key is required and that trend_opt_out=true opts the account out of future aggregated trend statistics that do not currently exist. However, it does not describe the response, whether the change is reversible, or what false means beyond implication.

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 short and front-loads the admin-key requirement, followed by the parameter effect and the reading alternative. The "see Terms" and "none exist today" asides are slightly tangential but do not bloat the definition.

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 mutation with no output schema or annotations, the description covers authentication, the setting's effect, the current absence of aggregated statistics, and the sibling tool for checking the setting. It is largely complete, though it could mention the update response or reversibility.

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%, so the description must compensate for the single boolean parameter. It explains that true opts the account out of contributing to future aggregated trend statistics and notes that none exist today, adding real meaning beyond the bare boolean schema. It does not explicitly define false, but the boolean inversion is clear enough.

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 identifies the resource (account settings) and the required admin key, and the parameter explanation makes clear that the tool changes the trend_opt_out setting. It does not explicitly say "updates" or "sets," but the purpose is inferable from the tool name and the per-setting explanation, and it distinguishes itself from get_usage.

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?

It gives clear context that this is an admin-key operation and explicitly points to get_usage for reading the current setting, which implies the division of labor between viewing and updating. It does not state explicit exclusions or when not to use it, but the alternative is named.

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