Set channel banner

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

Annotations already flag the write, open-world and idempotent profile, but the description adds genuinely non-obvious behavior: the banner is publicly visible and therefore requires prior user confirmation. That side-effect disclosure goes beyond what the annotations convey. It stops short of saying whether an existing banner is replaced or what a successful call returns, which is the remaining gap.

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?

Two compact sentences with no waste: the hard image constraints come first, then the approval requirement. Every clause carries operational information an agent needs before calling.

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 three-parameter mutation with no output schema, the definition covers the essentials: valid input format, visibility consequences and the confirmation handshake. It could be slightly more complete by stating what replaces the current banner and any per-account or quota limits, but nothing critical for calling it correctly is absent.

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 67%, and the one undocumented parameter, image_path, is exactly the one the description compensates for by specifying format, aspect ratio, minimum and recommended resolution, and size cap. The confirmation hint also gives the otherwise cryptically-named confirmation_token a workflow meaning. What is missing is any hint about error handling when an image fails the constraints.

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 ("Upload a channel banner") and pins down the channel-level scope, which naturally separates it from set_thumbnail and set_watermark. It never names those siblings explicitly, so an agent must infer the distinction from the resource name alone.

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 sentence "Public, so the user confirms first" implies a required two-step approval workflow, which is useful context. However, there is no explicit when-to-use or when-not-to-use guidance relative to alternatives like set_thumbnail or update_channel, leaving the routing decision implicit.

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