add_text

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

With no annotations the description carries the full burden, and it discloses meaningful traits: it renders via the system text engine with RTL support, auto-places on a free track above V1 unless trackIndex is set, and — importantly — the text clip is not editable afterward. It omits error behavior when no free track exists and what the call returns.

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 clauses with the verb and resource front-loaded; the engine note, placement rule, and edit limitation each add distinct information with no 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 17-parameter mutation tool with no annotations and no output schema, the description covers purpose, placement, and immutability well, but says nothing about the return value (e.g., created clip handle) or failure modes such as no available track.

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 82%, so baseline is 3, but the description adds real semantics for trackIndex (default is a free video track above V1) which the schema leaves entirely undocumented, and frames the font parameter as 'any installed font' with RTL support.

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 text title to the timeline', plus the rendering engine used (system text engine, installed fonts, RTL). It does not explicitly contrast with close siblings like add_text_captions or add_captions, so sibling differentiation is left to the agent.

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?

Placement guidance ('on a free video track above V1 unless trackIndex is given') implies how it is used, and the note that edits require remove-and-re-add clarifies a workflow constraint. But there is no explicit when-to-use-this-vs-alternatives guidance relative to the caption/graphics tools.

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