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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds value beyond them: it enumerates returned fields (platform, handle, id, default flag), explains the default-account semantics when a post names no account, notes multiple accounts per platform, and warns that not every network is live yet. That is substantive behavioral context an agent cannot get from the annotations.

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?

Front-loaded with the action and the imperative prerequisite, then return shape, then selection guidance, then a caveat. Four sentences with no filler; each adds a distinct, actionable fact.

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?

With no output schema, the description correctly carries the burden of describing returned fields and default-account semantics, and it flags the platform-availability caveat. It stops short of describing ordering of results or what an empty list means, which would fully close the loop.

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?

The tool takes zero parameters, so the baseline is 4; the description instead adds meaning to the output by explaining that "accounts" can be passed to create_post/queue_post/schedule_post to select one. Nothing about an input schema needs elaboration.

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 ("List all connected social media accounts") and implicitly separates itself from list_feeds/list_posts/list_presets by scoping to connected accounts. An agent can identify the resource and its scope without opening the schema.

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 an explicit ordering rule: "ALWAYS call this before create_post," and names the downstream tools (create_post / queue_post / schedule_post) that consume the result. The only missing piece is an explicit when-not, which is largely moot for a prerequisite listing tool.

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