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

Annotations already declare this as a non-read-only, non-destructive, non-idempotent operation, so the description does not need to restate safety. It adds useful behavior: Cardboard copies each file into the project and prepares it like an upload from upload_media's card, and the result reports each file's media id or why it was not added. It does not mention limits such as the 10-file maximum, but the core behavior is well disclosed.

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 front-loaded and mostly efficient: it starts with the action and resource, then adds the upload_media comparison, result behavior, and document exclusion. It is somewhat dense in a single paragraph, but every sentence contributes useful information.

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?

There is no output schema, and the description compensates by explaining that the result names each file's media id or why it was not added. It also covers the key behavioral context: copying into the project, accepted media types, photo handling, and the document exclusion. For this tool's complexity, the definition is complete enough for correct invocation.

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 coverage is 100%, so parameter documentation is already strong. The description adds meaning beyond the schema by listing accepted media formats, clarifying that files must be attached to the chat, and noting that a photo joins as an image. It does not explain file_id or download_url semantics, but those are covered by the schema.

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 a specific verb and resource: adding video, audio, and photo files attached to the current chat into a project. It also distinguishes this from upload_media by explaining that the files are already in the chat and do not need to be picked again.

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 clear usage context: this is for media already attached to the chat, and it names upload_media as the related alternative. It also gives an explicit exclusion for documents such as briefs, scripts, and shot lists, which should remain in the chat. It does not explicitly cover the case of files not already in the chat, but the intended context is clear.

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