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

With no meaningful safety annotations beyond readOnlyHint=false and destructiveHint=false, the description carries the behavioral burden. It discloses that the file is stored, lists supported formats, sets a 100MB limit, and specifies the exclusive-or relationship between url and filePath. It could add what the API returns (e.g. media ID) or overwrite/idempotency behavior, but the provided details go beyond the structured fields.

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?

Four sentences with no filler: purpose first, then storage context, format/size constraints, exclusivity rule, and a final usage trigger. Every sentence earns its place and the most actionable guidance appears early.

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 3-parameter, no-output-schema tool, the description covers the essential call constraints: source, format, size, exclusivity, storage destination, and intended use. The main gap is the lack of any hint about the return value (e.g. whether it returns a media ID or URL), which is more important given there is no output schema.

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 the baseline is 3. The description adds genuine value by explaining the mutual exclusivity of url and filePath, which is not captured in the property descriptions, and by constraining acceptable inputs via formats and size. This justifies one point above baseline.

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 clearly states the verb and resource: uploading a media file from a URL or local path into BulkPublish for use in posts. It also gives supported formats and a size limit, making the scope concrete. However, it does not explicitly differentiate this tool from siblings like create_media_upload or create_multipart_upload, so it misses the top-tier sibling-distinguishing evidence.

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 provides a clear usage context: 'Use this when the user provides an image/video to attach to a post.' It also states the either-url-or-filePath constraint. It does not name alternatives or give explicit when-not-to-use guidance, so it stops one step short of a 5.

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