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

Annotations already declare readOnlyHint: true, so the description is not required to restate safety. It adds behavior beyond annotations: returns change against preceding period, follower series, and notes that providerId remains valid after handle changes. These are non-obvious behaviors an agent needs to know.

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 information-dense, with no filler. It leads with the core function, then parameter behavior, then usage guidance. Every sentence earns its place, making it detailed yet efficiently structured.

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 output schema exists, the description needn't enumerate return values, but it still lists key metrics. With annotations covering safety, all parameters defaulted and scoping explained, and alternatives named, an agent has everything needed to call the tool correctly.

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 fully explain parameters. It does: defines period values and default, explains the optional platform scoping with channelName/providerId, and clarifies providerId's stability. This is significantly more than the schema provides.

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 tool aggregates performance metrics for one or all channels, and explicitly distinguishes it from sibling tools get_post_metrics and get_best_time_to_post. It names the specific metrics returned, making the purpose unambiguous.

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 provides explicit instructions on when to use the tool (e.g., 'how did LinkedIn do this month?'), how to scope by platform, and when to pass channelName vs providerId. It also tells when not to use it by pointing to alternatives, leaving no ambiguity.

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