Preflight media against platform rules

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safe, non-mutating profile is covered. The description adds useful context about what is checked and that it runs before post creation, but says nothing about what failing validation produces (errors vs warnings), reversibility, or rate limits, which is the main remaining gap.

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?

A single front-loaded sentence with a colon-delimited list of the concrete rule categories. Every clause carries information and there is no padding, though it is terse enough that it cannot afford to omit anything important.

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?

There is no output schema and no detail on the shape of the validation result (pass/fail, warnings, per-channel breakdown), and the parameters are undocumented in both schema and description. For a pre-creation gate that the agent must interpret, this is minimally adequate rather than 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% across four parameters, so the description must carry the burden. It loosely alludes to the inputs ('text and media', 'selected channels', 'asset types'), which partly maps to text, url/path, and channelIds, but it never explains the url-vs-path distinction or the expected format for channelIds.

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?

The description states a specific verb (validate) plus the resources (text and media) and the target (selected channels), and enumerates the concrete checks: text limits, required metadata, asset types, and the YouTube Shorts orientation rule. That is far more informative than the name alone. It does not explicitly distinguish itself from the sibling media_probe, which keeps it from a 5.

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 phrase 'before creating a post' gives clear situational context and implies this is a pre-step to buffer_create_post. It stops short of stating exclusions or naming media_probe as the alternative, so it lacks full when-not guidance.

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