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

Annotations already declare readOnlyHint=false and destructiveHint=false, but the description adds the non-obvious behavior that "all" expands to every eligible network and that omitted or unsupported networks return in a skipped list with a reason. That partial-success semantics is real behavioral context beyond the annotations; it stops short of covering permissions or duplicate handling.

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?

Three compact sentences, each carrying a distinct fact: drafting behavior, the "all" expansion and skip semantics, and the publishing gate. The media-sourcing sentence is slightly tacked on but still earns its place by preventing invalid media URLs.

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 5-parameter mutation tool with a fully documented schema and no output schema, the description covers the state change (draft, not published), the fan-out behavior, and the media source restriction. The skipped-result detail is the only return-value information given and it is the critical one.

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% and the schema already documents each field, including per-network sub-properties. The description only adds meaning for the "networks" value "all" and for the skipped return, which is marginal added value over the schema baseline.

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 ("Saves a new post as a draft") and names the product, PersonaXpand. It distinguishes itself from the publishing siblings by explicitly saying nothing goes out until schedule_post or publish_post_now.

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 explicitly names the alternatives (schedule_post, publish_post_now) and the condition that selects them, plus a constraint on media sourcing that points to list_media, get_image_result and the import tools. An agent knows when to call this tool versus its siblings.

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