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

Annotations already declare readOnlyHint/idempotentHint/non-destructive, so the safety profile is covered. The description adds real behavioral context beyond that: metrics are network-dependent and 'some nothing', results are broken out by day with change deltas, and the day window is constrained to 7/30/90. It could go further on empty-result handling or auth, but it adds value.

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 core scope is front-loaded in the first clause, which is good, but the trailing 'Free. Free.' is duplicated filler with ambiguous meaning and dilutes an otherwise compact two-sentence description.

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?

With no output schema, three optional parameters, and moderate schema coverage, the description covers the essentials (what is returned, granularity, window) but leaves gaps: no mention of authentication/connected networks requirement, what happens when a network reports nothing, or the shape of the 'change' field. Adequate but not 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?

Schema coverage is 67%; post_id and channel_id are already documented as coming from social_post/social_posts and social_channels. The description compensates for the undocumented `days` enum by explaining it as the lookback window, and clarifies the scope each ID selects, which is meaning beyond the raw schema.

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 states a concrete resource and result: per-day metrics (followers, impressions, likes) for a channel over 7/30/90 days or for a single published post, including change values. That distinguishes it from siblings like social_posts or social_post, which deal with post content rather than numbers. It is not a tautology of the title 'Read social numbers', though the phrasing is a bit informal.

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 makes the channel_id vs post_id selection reasonably clear by tying each to a scope ('How a channel did...' vs 'one published post'), and the days enum is spelled out. However, it names no alternative sibling tool, gives no explicit 'do not use this for X' guidance, and offers no prerequisites such as connecting a network first.

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