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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the additive mutation nature is known. The description adds valuable behavioral context: the tool uses the configured posting schedule, refuses a channel with no times and adds nothing for it, and defaults to the first connected account unless platform_account_ids is passed. It stops short of describing return values or partial-failure behavior across multiple channels.

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?

The description is front-loaded with the core action and follows with tightly scoped prerequisites and targeting behavior. Every sentence adds useful information, and there is no repetition or 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?

For a mutation tool with four parameters including a nested object, the description covers purpose, operational constraint, prerequisite, and account targeting. It omits potential return values or error handling beyond the no-posting-times case, but with no output schema and strong annotations, it is nearly complete.

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 100%, so the schema already documents each parameter thoroughly. The description adds meaning beyond the schema by explaining the default account selection behavior for platform_account_ids and the prerequisite for Instagram media on the platforms parameter, though it does not cover variance_minutes or all parameter nuances.

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?

The description opens with a specific verb and resource: 'Add a post to the next available queue slot.' It immediately distinguishes this from alternative scheduling tools by noting it uses the configured posting schedule and routes to add_queue_times when no schedule exists. An agent can tell it apart from schedule_post or add_queue_times without opening schemas.

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?

It explicitly states a prerequisite (channel with no posting times is refused; use add_queue_times first) and gives a clear condition for platform_account_ids. However, it does not compare directly against siblings like schedule_post or publish_post, so the when-to-use versus those alternatives is left implicit.

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