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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true. The description adds real value beyond that: it enumerates the exact returned fields (totals, deltas, engagement rate, platform/content breakdowns, series, data-quality flags, top posts) and flags 'Free' cost. This is meaningful behavioral context that annotations alone would not convey.

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 purpose, followed by a compact enumeration of return contents, then usage guidance and cost. No filler sentences, though the return-field list is dense and could be tightened.

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 work of describing the return shape via its field enumeration, which is the key missing structured data. Combined with the usage cue and cost note, it is nearly complete for an analytics read tool. Slightly less than full because the days window semantics (7/30/90) and source-specific behavior are not explained.

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 only 33%, but the enum for source and the const values for days are self-documenting in the schema, and targetId carries its own pattern and description. The description adds the semantic distinction that the target can be either a connected brand or a managed account, which is useful but modest. Baseline 3 given the partial coverage.

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?

States a specific verb (return) and resource (analytics snapshot) with the two valid target types (Social Brand or hosted managed account). Distinguishes itself from siblings like get_social_post or list_social_posts by scope, though it never explicitly names an alternative.

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?

Explicitly says 'Use this before making performance claims or content recommendations,' which gives clear context for invocation. No when-not-to-use conditions or named alternatives, so it stops short of the top score.

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