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

Annotations already establish readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: metrics are populated for Twitter/Instagram but only publish status + URL are returned for LinkedIn/Threads/TikTok, which prevents misreading empty metrics as zero engagement. Auth, rate limits, and error behavior remain undescribed.

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?

Two sentences, zero waste, with the core action front-loaded and the platform-coverage caveat following. Both sentences carry load: the first defines the tool, the second prevents a misinterpretation of the output.

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?

An output schema exists, so return-value structure need not be re-explained, and the description instead supplies the one thing that matters most for correct interpretation: which platforms actually return engagement data. For a single-required-param read tool, this is 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 description coverage is 0% and the single postId parameter carries no description, so the schema does not explain it. The name 'postId' is fairly self-describing, but the description adds nothing about expected format, where to obtain the ID, or validity constraints, so the description does not compensate for the coverage gap.

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?

Specific verb (Fetch) + resource (engagement metrics: likes, comments, shares, impressions) + scope (a published post across every platform it was sent to). This clearly distinguishes it from get_post, get_publish_status, and get_channel_analytics, which an agent can tell apart without opening any schema.

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?

The 'for a published post' framing and the per-platform return caveat give a clear sense of when this tool is appropriate versus draft-facing tools. However, it never names an explicit alternative (e.g. get_channel_analytics) or an exclusion, so the routing is implied rather than stated.

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