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

With no annotations, the description carries the full behavioral burden for a mutation tool, yet it does not state side effects on existing refs, permission/auth needs, or reversibility. The legacy-compatibility note overlaps with the schema's alsoSetPrimaryMediaId description, so little new behavioral context is added.

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 tight sentences, with the core purpose front-loaded and the role enumeration immediately useful. No filler or redundant phrasing.

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 schema is rich and fully documented, which offsets the missing output schema, but for a nine-parameter mutation tool with zero annotations the description is thin on consequences and edge cases. It is minimally adequate but leaves gaps an agent would want filled.

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 all nine parameters are already documented, giving a baseline of 3. The description's mention of roles and legacy media ids restates what the schema already provides rather than adding syntax or format detail.

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 ("Add a fine-grained media reference to a shot") and enumerates the exact role values, so an agent understands the operation immediately. It does not explicitly distinguish itself from close siblings like update_shot_media_ref or delete_shot_media_ref, leaving that to the name.

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?

Usage is only implied by the verb and the role list; there is no explicit when-to-use versus update_shot_media_ref or add_media_overlay, and no stated prerequisites. The one contextual hint (legacy compatibility) is a behavior note rather than routing guidance.

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