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

Annotations only cover the safety profile (not read-only, not destructive, open-world); the description goes well beyond them, disclosing consequential platform behaviors such as photos being cropped to the first photo's shape in Instagram/LinkedIn carousels, LinkedIn converting photos into a PDF carousel, per-network media-count limits, and timezone interpretation of scheduledAt.

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 opening sentence front-loads purpose and modes effectively, and the dense platform detail is largely justified by 18 parameters and eight nested settings objects. It is delivered as one long undifferentiated paragraph, so scanning is harder than it needs to be and a few clauses restate schema content.

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?

For a high-complexity, 18-parameter mutation tool the platform semantics are covered thoroughly, including the partial error path for Reddit flair. The remaining gap is that, with no output schema, the description never says what a successful call returns (post id, per-account results), which an agent needs to chain follow-up calls.

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 100%, so the baseline is 3, but the description adds real conditional meaning the schema does not encode — which networks require media, which settings objects apply to which target, and platform-specific quirks (Tumblr photo caps, Hashnode Pro requirement, Google Business 1,500-character limit).

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 and resource ('Create a social media post') and immediately enumerates the three operating modes: schedule, publish immediately, or save as draft. The per-network elaboration makes it unmistakable against siblings like update_post or delete_post.

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?

Gives explicit routing guidance: 'use upload_media first for reliable hosting' and 'use list_pinterest_boards' for the board id, plus the conditional rule that media is REQUIRED for Instagram/TikTok/YouTube/Pinterest except drafts. The mode selection (draft vs publishNow vs scheduledAt/useNextSlot) is spelled out rather than inferred.

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