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

With destructiveHint=true, idempotentHint=true and openWorldHint=true already declared, the description adds real context: caption/media/destinations are preserved, and the call requires access to every destination plus subscription allowance. These permission and side-effect details go beyond the annotations. It stops short of describing what 'destructive' means here (e.g. whether the original time is lost) or the failure mode when allowance is exhausted.

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, front-loaded with what the tool does, then the preservation guarantee and the eligibility/permission constraints. No filler.

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?

No output schema exists, but the tool is idempotent and returns little of interest, so the description need not explain return values. Safety is covered by annotations and preconditions and permission requirements by the description, leaving only minor gaps around failure behavior and postId.

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 50%: scheduledAt is documented as a future ISO 8601 time with timezone, and the description repeats the 'future ISO 8601' framing. postId carries no description in either the schema or the description, so half the parameters remain undocumented and the description does not compensate.

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 (moves/reschedules), resource (existing scheduled post), and target (future ISO 8601 time), which cleanly separates it from create_post and cancel_post. The added preconditions on drafts and published posts further pin down exactly what the tool operates on.

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 when-not rule ('Drafts and published posts cannot be rescheduled') and implicitly scopes usage to already-scheduled posts. It does not name a sibling alternative (e.g. cancel_post or create_post) for the cases it excludes, so it stops short of a 5.

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