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

With no annotations, the description carries the full burden, and it does disclose real behavior: the 10-minute future scheduling rule, server-side media fetching, and a 25 MB per-file cap. However, it says nothing about the publish outcome, permission/auth requirements, rate limits, or whether the created post is immediately live, leaving meaningful gaps for a creation 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 dense sentences with the core capability front-loaded and constraints following immediately. No filler, though 'media_urls are fetched server-side' could be marginally clearer about what that implies for the caller.

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 creation tool with no annotations and no output schema, the description covers scheduling and media adequately but omits what happens after creation (e.g., post identifier returned for later update/cancel) and any permission prerequisites. It is functional but not complete for the full create-post workflow.

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?

Beyond the schema's 75% coverage, the description adds semantics the schema lacks: scheduled_at must be at least 10 minutes in the future, and omission means draft; media_urls are fetched server-side with a size limit. It does not clarify the platforms parameter beyond what the schema already documents.

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 and resource ('Create a draft or scheduled post') and immediately clarifies the two operating modes via the scheduled_at flag. It does not explicitly distinguish itself from siblings like update_post or cancel_post, but the create semantics are unambiguous from the name and first sentence.

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?

It clearly tells the agent when to omit scheduled_at (draft) versus provide it (scheduled), and gives the timing constraint that governs that choice. It stops short of naming alternatives such as update_post for editing an existing post, so there is no explicit when-not guidance.

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