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

Annotations already declare readOnlyHint/non-destructive/closed-world, so the bar is lower, yet the description adds real value: it reads actual platform config, evaluates only ENABLED channels, and surfaces a non-obvious caveat that a later library upload does not repair a creative saved without a Meta video_id. It stops short of describing the exact blocker/report structure.

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-loads the core purpose in the first sentence and follows with the per-channel evaluation logic and a specific gotcha. The video_id caveat is dense but earns its place; no filler sentences.

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 read-only one-param tool with no output schema, the description adequately covers inputs (wizard campaign), what it evaluates per enabled channel (ads, audience, offer, budget, connection), and outputs (blockers). The precise return shape is only loosely described, a minor gap.

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?

With a single parameter at 100% schema coverage, the schema already documents campaign_id fully. The description adds only the 'draft campaign' framing, not new syntax or constraints, so the baseline 3 is appropriate.

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 ('Check whether a draft campaign is ready to launch, per channel') and clarifies it reads real platform config. An agent can distinguish it from launch_campaign (performs the launch) or get_campaign_by_wizard_id (fetches config) without opening the schema.

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 pre-launch validation context is clear from 'ready to launch' and 'reports blockers,' strongly implying it is called before launch_campaign. However, it never explicitly names launch_campaign as the follow-up action or states exclusions, so the routing is implied rather than spelled out.

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