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

Annotations indicate this is a non-read-only operation (readOnlyHint: false) and not destructive (destructiveHint: false). The description adds a note about duplicate behavior, which clarifies response semantics but does not disclose the tool's side effects (e.g., whether an upload target is persisted, whether a confirm step is required, or any permission requirements). The opening phrase 'A presigned target plus the URL' is more about the response than the action, so it provides minimal behavioral detail beyond what annotations already convey.

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 short (two sentences plus an endpoint), but it is not well-structured: it leads with an output description rather than the tool's action, then interleaves a conditional response detail, and finally appends the HTTP method and path. The key information (what the tool does) is buried and could be expressed more directly. It is concise in length but not in clarity.

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 description omits critical context: what to do with the returned presigned URL (i.e., how to upload the bytes), whether a confirmation step (community_confirm_post_image_upload) is required, how the contentHash affects behavior beyond the duplicate flag, and the full response structure. Without an output schema, the agent cannot reliably interpret the response. The tool's complexity is moderate, but the description leaves significant gaps.

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 only 50% (mimeType and contentHash have descriptions; fileName and sizeBytes do not). The description adds no explicit parameter explanations; it only indirectly references contentHash via the duplicate deduplication note. It does not compensate for the undocumented fileName and sizeBytes parameters, leaving the agent to infer their meaning from names and constraints alone.

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 title clearly states the action ('Request an upload target for a post image'), and the description includes the REST endpoint, so an agent can infer what the tool does. However, the description's first sentence describes the output rather than the action itself, and it does not explicitly differentiate this from sibling tools like assets_create_upload_url or assets_create_text_upload_url. The purpose is adequately clear but not crisply stated.

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 gives no guidance on when to use this tool versus alternatives such as assets_create_upload_url or community_confirm_post_image_upload. It does not mention the two-step flow (request then confirm) or any conditions that would make this the correct choice. There is no when-to-use or when-not-to-use information.

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