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

Annotations already declare destructiveHint=true, openWorldHint=true, and idempotentHint=false, so the safety profile is partly covered. The description goes beyond them by disclosing that the retweet is PUBLIC and that the user must confirm first — a genuine behavioral consequence the annotations do not convey. It stops short of describing rate limits or the no-op-vs-error result of an undo on an un-retweeted post.

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, zero filler. The primary action is front-loaded, the undo path follows, and the confirmation warning is the final emphasis where it matters most.

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 mutation with no output schema, the description covers the action, the inverse action, and a public-visibility warning, which is most of what an agent needs. It does not mention the idempotencyKey retry semantics that the schema defines, which is a notable omission for a non-idempotent write, but the schema carries that detail.

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 100%, so tweetId and undo are already documented in the input schema. The description confirms the meaning of tweetId and undo: true but adds no format, constraint, or edge-case detail (e.g., behavior of undo when no retweet exists, or how accountId selects the connected account). Baseline 3 is appropriate when the schema does the heavy lifting.

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 (Retweet) plus the resource (a post on X) and names the exact identifier parameter (tweetId), and also covers the inverse operation via undo. An agent can distinguish it from adjacent X actions like bookmark_on_x or follow_on_x 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?

Explicitly tells the agent how to invoke the inverse operation (undo: true) and adds a real precondition: confirm with the user because the action is public. It does not name or contrast with sibling X tools, so it falls just short of full when/when-not routing, but the usage context is clear.

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