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

Annotations already declare readOnlyHint/openWorldHint, but the description adds non-obvious state semantics — a TikTok reads 'sent' until TikTok names the video — and a rendering note about MCP Apps hosts. These are behavioral details the annotations do not convey, though no auth or rate-limit context is given.

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?

Four tight sentences, front-loaded with what is returned and the sibling exclusion. The MCP Apps card note is slightly niche but still earns its place as rendering behavior.

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 supplies the return shape (one line per network with the listed fields), the default-parameter behavior, and an edge case for TikTok status. Complete enough to call 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 100% and the single parameter is already documented in the schema; the description's 'without it, the most recent published post' essentially repeats that. Baseline 3 applies since the schema carries the parameter semantics.

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?

Names a concrete resource (one post's results) and enumerates the returned fields (where it went, status, views, likes, link), and explicitly distinguishes itself from get_metrics. An agent can pick this over the sibling without opening either 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?

States the exact question it answers ('how did my post do?') and names the alternative tool it is NOT (get_metrics), plus explains the optional postId default. Explicit when-to-use and when-not-to-use routing.

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