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

Annotations only declare readOnlyHint=false, so the description carries the burden and adds nothing: it does not say the update is partial (unspecified fields left unchanged), whether the clip must be a text clip, whether a track lock blocks it, or what is returned. For a mutation with a nested position object, this is thin.

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?

A single front-loaded sentence with zero filler and the mutable fields trailing the verb+resource. It is efficient, though the brevity comes at the cost of the behavioral and usage detail the other dimensions need.

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?

With no output schema, minimal annotations, a nested position object and only 33% schema coverage, the description is not complete enough: partial-update semantics, unit conventions and the non-text-clip failure mode are all unaddressed.

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 33% and only clip_id/project_id are documented in the schema; the description usefully groups the remaining undocumented parameters by naming content, position and timing. However it never explains that timing maps to start_time_ms/duration_ms, that units are milliseconds, or that one of x/y is optional relative to the other.

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 (update) and resource (existing text clip) plus the fields it can change (content, position, timing), which is far more informative than the title alone. It does not distinguish itself from the close sibling studio.update_clip, leaving the agent to infer that this is the text-overlay-specific variant.

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 word 'existing' weakly implies the clip must already exist and points away from studio.add_text_overlay, but there is no explicit when-to-use / when-not-to-use guidance and no mention of studio.update_clip as the generic alternative. An agent choosing between the two update tools gets no help.

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