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

With no annotations, the description carries the full behavioral burden, and it does add real context: the server is hosted and cannot read local files, so media must be a public URL or base64, and omitting scheduledFor publishes immediately. It says nothing about authentication, per-platform partial-failure behavior, rate limits, or whether a scheduled post can later be cancelled, which is a notable gap for a multi-platform write tool.

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, no filler, and the core action is front-loaded ahead of the operational constraints. Each clause (media sourcing, immediate-vs-schedule) carries distinct information.

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 10-parameter mutation tool with no output schema and no annotations, the description covers the highest-risk ambiguity (media sourcing) and the scheduling switch, but leaves platform-specific metadata expectations, multi-platform failure semantics, and required-field behavior (caption/platforms/mediaKind) unaddressed. Adequate but with clear gaps.

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 80%, so the baseline is 3, but the description adds a cross-parameter relationship the schema never states: media is supplied through either mediaUrl/imageUrls or mediaBase64, an either/or choice. The scheduledFor guidance duplicates the schema's own "omit to publish immediately" text, so the gain is real but partial.

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 and publish (or schedule) a video or image post") plus the destination scope (connected platforms). It is trivially distinguishable from siblings like update_post, delete_post, and retry_post, since it is the only creation tool in the set.

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 conditional guidance: "Omit scheduledFor to publish immediately" versus supplying it to schedule, and constrains the media source (public URL or base64). It does not name alternatives (e.g. use update_post to modify an existing post) or mention prerequisites such as connecting accounts, so it stops short of a full when/when-not treatment.

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