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

Annotations already indicate this is a non-read-only, non-destructive write operation. The description adds meaningful context beyond annotations: per-platform limits, enforcement at publish time, unsupported platforms, and how the returned upload_id is consumed. It does not cover failure behavior or idempotency semantics, but the schema handles idempotency.

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 purpose and workflow are front-loaded, and each sentence is information-dense. The platform-limit list is long but specific and relevant; it is arguably more detailed than strictly necessary for invoking this tool, since limits are enforced at publish time.

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 four-parameter creation tool with full schema coverage, annotations, and no output schema, the description is complete enough: it explains purpose, prerequisites, ordering, platform constraints, unsupported platforms, and how the returned upload_id is used downstream.

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 the schema documents workspace_id, child_upload_ids ordering/min/max, cover_index, and idempotency_key. The description reinforces that upload IDs are passed in display order, but adds little parameter detail beyond what the schema already provides.

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: 'Groups multiple already-uploaded media items into a single carousel post.' It clearly distinguishes this tool from siblings by describing an intermediate assembly step before create_post_draft publishes the carousel.

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 the required workflow: upload media first via create_video_upload or create_video_upload_from_url, pass upload IDs here in display order, then use the returned upload_id with create_post_draft. It also names platforms that do not support carousels, giving clear exclusions.

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