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

The annotations already flag destructiveHint=true and idempotentHint=true, and the description adds genuinely useful partial-failure semantics: each field saves independently, and unusable values are reported with reasons while the rest persist. However, it never addresses the destructive profile the annotations declare, such as whether re-calling overwrites previously chosen music, branding, or pace. The per-field error reporting is a real contribution beyond schema and annotations but leaves the mutation risk unexplained.

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 sentences, front-loaded with the purpose and the timing cue before the field list. The opening sentence is long and parenthesis-heavy, packing four parameters and two defaults into one clause chain, but every element carries information and nothing is redundant.

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 12-parameter tool with a nested address object and an output schema, the description covers all the meaningful field groups and the failure mode, so an agent can call it without guessing. Minor gaps remain: parameters like name, beds, baths, price, and description are only gestured at as "listing facts," and the overwrite behavior implied by destructiveHint is 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 description coverage is 100%, so the baseline is 3 and the schema already documents every parameter including the nested address object and both enums. The description adds some default-value information the schema lacks (default song, default branding) and restates the photo-limit constraint on videoPhotoCount. It does not describe the loosely named "listing facts" the way it enumerates the other fields.

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 names the resource (the draft's optional basics) and enumerates exactly what can be set: song, branding, videoPhotoCount, pace, and address/listing facts. The timing relationship to start_video is stated explicitly. It does not differentiate from sibling setters such as set_music, set_pace, or set_contact_card, which appear to overlap with these fields.

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?

It gives clear context for use ("Optional choices before start_video"), signaling these are pre-render settings and that none are mandatory. It also supplies defaults (Reel-E's first library song, saved brand kit when one exists), which tells the agent it can omit optional parameters. It stops short of naming alternatives or describing when a finer-grained setter would be preferable.

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