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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description contributes real extra behavior: some values are 'marked thin' and need caveating, views/engagement are aggregated across all accounts rather than per-account, and `findings` are derived numbers that may be wrong. It stops short of describing response shape or pagination/volume limits.

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?

Front-loaded with the per-account scope and metric list, then the cross-account exception, then presentation rules. It is dense and slightly run-on, but nearly every clause carries actionable information about output content or how to report it.

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, the description does the necessary work of enumerating returned metrics, the top-3-posts payload, the comparison basis, and the `findings` block. It still leaves the exact response structure and behavior when no accounts are visible unspecified, but is sufficient to call and interpret 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 coverage is already 100%, so the baseline is 3; the description earns above that by explaining that `days` defines a window that is automatically compared against the equivalent preceding window, which the schema does not say. It adds no extra detail on `profile_ids` beyond the schema's own text.

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 names the resource precisely (per-account engagement metrics: comments, public replies, automated DMs, new contacts, emails captured, top 3 posts) and states the comparison scope. It never names a sibling, so an agent cannot tell from this text alone why it should pick this over sprkly_get_analytics or sprkly_get_account_summary.

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?

Usage is only implied through the shape of the output (a rolling `days` window with prior-period comparison) and the instruction to treat `findings` as a starting point to verify. There is no explicit when-to-use, when-not-to-use, or named alternative among the many summary/analytics siblings.

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