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

Annotations only flag readOnly=false, destructive=true, openWorld=true; the description goes further by explaining the side effect concretely — a draft is created for the account, the script/voice/notes are stored, and the result appears in list_pending_reels and the calendar. It also explains what is returned (desktop-app links, Codex, download pages), which annotations can't convey. It stops short of saying what is overwritten when a pieceId is supplied, which matters given destructiveHint=true.

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?

It's a single dense paragraph that front-loads the operating condition before the action, which is defensible but delays the core verb. Nearly every sentence carries new information (scope, side effects, return value, the when-not), with minimal waste.

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 10 parameters, no output schema, and a destructive write, the description covers the gaps that matter: where the record lands, what the caller receives back, and which environment this tool is for. An agent can decide and call correctly from this plus the fully described schema.

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 100%, so the baseline is 3; the description earns a bump by tying meaning to specific parameters — 'stores the script, the voice and the notes as a pending video' and 'creates a draft for the account' clarify the roles of voice, notes and accountId. It adds context rather than repeating field text.

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 states a concrete verb and resource — saving an approved reel/video plan as a pending video in Ignix — and names the sibling that produces the plan (get_reel_playbook) and the ones the result surfaces in (list_pending_reels). It's clearly distinguishable from generate_video or plan_video_edit because it explicitly says the render happens later on the user's computer.

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 an explicit precondition (chat cannot run commands — web or mobile), an explicit prerequisite (user has approved the script), and an explicit when-not ('Not needed where you can run commands: there, make the video right away'). The alternative path is named rather than left to inference.

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