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

Annotations only say readOnlyHint=true; the description adds real behavioral context not in structured data — the two alpha profiles preserve transparency and are REFUSED unless the sequence carries an alpha source (cut-out layer element or kept Switch X alpha track). That refusal rule is exactly the kind of precondition an agent needs. It does not describe the response shape, but that is a minor gap for a read-only listing.

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?

Front-loaded with the core purpose and the routing instruction, then the alpha caveat. The parenthetical detail about ProRes 4444 / RGBA PNG zip is slightly heavy but each clause carries actionable meaning, so waste is minimal.

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 zero-parameter, read-only listing with no output schema, the definition supplies everything needed: the full valid value sets, the sequencing relative to lab_start_export, and the alpha-source precondition. No material omission remains.

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?

The tool takes zero parameters, which sets the baseline at 4. The description still adds meaning by enumerating the two value families (7 profiles, 3 quality presets) the caller will choose from, information the empty schema cannot supply.

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 ('List the available export delivery profiles ... and quality presets') and enumerates the exact valid values. It is clearly distinguishable from siblings such as lab_list_exports/lab_get_export (existing exports) and lab_start_export (performing the export).

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?

Explicitly instructs 'Call this before lab_start_export to pick a valid profile/quality', naming the sibling and the condition that selects it. It lacks any when-not guidance (e.g., that it is unnecessary once a profile is already known), so it stops short of a full 5.

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