threads_create_image_post

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only states that it creates and publishes a post, but does not mention authentication requirements, rate limits, what happens on failure, or whether the image is fetched from the URL server-side. It also doesn't describe the response structure beyond relying on the output schema.

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 concise, with a clear first sentence and a compact Args list. It includes the internal 'ctx' parameter, which is not part of the user-facing schema, adding a small noise. Overall, it is well-structured and front-loaded with the main action.

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?

The tool has an output schema, so return values are presumably covered elsewhere. However, for a mutation tool with no annotations, the description lacks essential context such as authentication, whether the post publishes immediately, and any constraints on the image URL. It is minimally viable but leaves gaps in operational understanding.

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 input schema has zero descriptions for image_url and text, and only a minimal description for reply_control via the $defs. The description compensates by listing each parameter with brief semantics: 'URL of the image to post', 'Optional text content', 'Who can reply - ...'. While not deeply detailed, it adds meaningful context beyond the schema's bare field names and enum.

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 states 'Create and publish a post with an image to Threads', which is a specific verb+resource+scope. It clearly distinguishes from sibling tools like threads_create_post and threads_create_video_post by focusing on image posts.

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?

The description implies usage for image posts via the tool name and the image_url parameter, but it does not explicitly compare with alternatives or state when to use this tool over others. For example, it doesn't say 'use this for images, use threads_create_post for text-only posts.' Thus, usage is implied but not explicit.

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