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

Annotations already flag destructiveHint=true and idempotentHint=false, but the description adds materially new behavior: publication is irreversible and public once the time arrives, Auto-DM rules survive unscheduling, platforms are added/removed by list diffing, and a passed confirmed time is rejected rather than silently moved.

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?

Dense but front-loaded: the core action and the confirmation requirement come first, followed by timing rules and then platform-set semantics. A few sentences (the relative-vs-absolute margin rule) are layered and require a second read, but none are 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?

Given destructive writes, nested platform entries and an available output schema, the description covers the preconditions, timing constraints, rejection behavior and platform diffing an agent needs. Return values can be left to the output schema.

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 nested schema already documents scheduled_at and timezone well, so the description's added value is operational: the UTC basis (server now via retrieved_at), the 10-minute floor, the 15-minute margin for relative requests, and exact sending of confirmed absolute times. It does not cover natural_posting or timezone behavior, leaving some schema-documented fields without narrative.

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 ('Update the scheduled time and/or platform set for a SCHEDULED post') and scopes it to posts already in SCHEDULED status. It is clearly separable from schedule_post, unschedule_post and get_schedule, which it names.

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 routes the agent: use unschedule_post to cancel all platforms, get_schedule to inspect current state, and a non-empty platform_schedules is mandatory here. It also states the precondition of explicit user confirmation and that a replacement time is the user's choice, not the tool's.

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