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

Goes well beyond annotations (readOnlyHint=false, destructiveHint=false, idempotentHint=false) by disclosing that the result 'lands as a draft' rather than publishing, that it is filed under an auto-created 'your own posts' campaign, and that approval plus publish/schedule are required for the post to go live. It also explains the image is attached as-is with no text overlaid.

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?

Front-loaded with the core action and efficient throughout, but the heavy parenthetical nesting ('a campaign Rebbel keeps for these automatically — no campaignId needed') makes a single dense paragraph that is slightly harder to scan than it needs to be.

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 no output schema, it covers the full lifecycle: what gets created, its draft state, where it is stored, and the required follow-up steps. Combined with fully covered parameters, nothing needed to call it correctly is missing.

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%, so every parameter is already documented — baseline 3. The description reinforces relationships (mediaLibraryAssetId comes from upload_brand_image, why there is no campaignId) but adds little syntax beyond what the schema already states.

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 — 'Creates a post from the user's own exact copy' — and pins the differentiator ('used verbatim, never rewritten by an LLM'). It implicitly separates itself from create_post/draft_first_post by declaring no brand guide or strategy is needed, so an agent can route 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?

Gives a clear when-to-use condition (the user supplies their own exact copy) and then the full follow-up workflow: 'call approve_post, then publish_post or schedule_post to actually post it.' It also names the alternative path implicitly by noting no campaignId is required, so the agent knows it does not need create_campaign first.

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