Add intro/outro

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

With no annotations, the description carries the full burden and does it well: accepted formats and size/duration limits, duplicate semantics ('the same file twice returns the existing item'), and the returned object shape { id, name, kind, durationSec, duplicate, restored }. It also scopes setDefault to new projects. This is unusually rich behavioral disclosure for a mutation tool.

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?

Three tight sentences with no filler, front-loaded with the core action and its constraints before the routing note about set_project_bumpers. Every clause carries 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?

No output schema exists, so the description's inline return shape is a genuine asset, and with no annotations it adequately covers limits, idempotency, and defaults. It stops short of stating permission/auth requirements or what happens if both url and uploadId are omitted (all 5 params are optional).

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 the baseline is 3, but the description adds real meaning beyond the schema: the url-vs-uploadId mutual alternative and the new-projects-only scope of setDefault. It does not explain imageSeconds, which is left entirely to 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?

States a concrete verb (add) plus the resource (video/image bumper) and the two accepted input sources (public url or uploadId). An agent can distinguish this from rename_bumper, list_bumpers, or set_project_bumpers without opening a schema.

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?

It explicitly routes the 'make this the default' case: setDefault affects NEW projects only, and existing ones require set_project_bumpers. That names an alternative and the condition selecting it. It does not, however, spell out when to use add_bumper versus list_bumpers/restore_bumper, though those are largely self-evident from the name.

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