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

Annotations already declare destructiveHint=true, readOnlyHint=false and openWorldHint=true; the description adds real value beyond them by disclosing the plan/entitlement prerequisite and the timestamp validity constraint. It still omits what happens if the post is already scheduled or published (overwrite vs. error) and any rate limits.

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 tight sentences that front-load the action and follow with prerequisites and the timestamp constraint; nearly every clause carries information. Slightly redundant with the schema's own note about the timestamp being in the future.

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 two-parameter mutating tool with no output schema, the description covers purpose, entitlement requirement, and the key input constraint. Missing only edge-case behavior (rescheduling/idempotency, error conditions), which the annotations' destructive flag makes somewhat important.

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% and both parameters are documented in the schema, so the baseline is 3. The description restates the future-UTC requirement already present in scheduledDateTime's schema description, adding no syntax or format detail beyond it.

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 (schedule) and resource (a Postel draft) and clarifies the target platform is derived from the post. It is distinguishable from publish-post (immediate) and create-post, though it does not explicitly name the sibling it differs from.

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 a clear precondition (a plan that includes scheduling) and a hard constraint (scheduledDateTime must be a future UTC ISO-8601 timestamp), which tells the agent when this call will succeed. It stops short of stating exclusions, e.g., how it relates to publish-post or whether an already-scheduled post should be updated instead.

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