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

With no annotations, the description carries the full behavioral burden. It does disclose two useful traits -- the placeholder and its prompt are preserved for provenance, and its status flips to 'generated' -- but omits whether the replacement is reversible, what happens to any previously linked asset, and how the required expectedVersion optimistic-lock behaves on conflict. For an unannotated mutation tool, that leaves significant behavioral gaps.

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 action front-loaded and the side effect on status clearly appended. The '§11.7, §18.2' spec references add little for an agent deciding how to call the tool, but the rest is free of filler.

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 four-parameter mutation with no annotations, no output schema, and zero schema description coverage, the definition should explain the version-check contract and the preconditions on assetId. Neither is covered, so an agent could invoke it without understanding failure modes or ordering constraints.

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 0% across four required parameters, so the description must compensate and largely does not. It implies the meaning of placeholderId and assetId through the prose, but says nothing about projectId scoping or the role of expectedVersion, which is the least self-explanatory parameter in the set.

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 uses a specific verb and resource pair: 'point a placeholder at a real uploaded/generated asset,' which is unambiguous about the operation. It does not explicitly distinguish itself from related siblings such as timeline.add_placeholder or asset.upload, which is the only thing separating it from a 5.

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 phrase 'real uploaded/generated asset' implies the assetId must already exist from a prior upload or generation step, which hints at a precondition. However, there is no explicit when-to-use guidance, no statement of when this should not be used, and no mention of the expectedVersion concurrency requirement or what happens on a version mismatch.

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