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

Annotations already declare non-read-only, non-destructive, open-world behavior. The description adds genuinely new traits: campaigns are created in PAUSED state (so nothing serves until explicitly activated) and a dry_run preview mode is available. It does not mention account/permission requirements or what the dry run returns, which keeps it short of a 5.

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 sentences, front-loaded with the create action and the PAUSED default, then the optional budget, then the sequencing advice. Every clause carries information an agent needs; no filler or restatement of the title.

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 10-parameter mutation tool with no output schema, the description covers the critical unknowns: default paused status, optional budget fields, dry-run preview, and the downstream tool chain. Remaining gaps (return payload of a dry run, account/currency resolution) are minor rather than blocking.

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 50%, with name, dry_run, end_time, objective, and lifetime_spend_cap undocumented in the schema. The description recovers meaning for objective, the two budget fields, and dry_run's preview intent, but says nothing about name constraints, end_time, start_time, language, folder, or account selection. That is useful but partial compensation.

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 ('Create a Snapchat campaign') and immediately adds the key qualifier that it is created PAUSED with an objective. It also names the follow-on siblings (snapchat_create_adsquad, snapchat_create_ad, snapchat_duplicate), so an agent can place it in the workflow without opening any 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?

Gives clear routing guidance: use this to create, then snapchat_create_adsquad and snapchat_create_ad for children, or snapchat_duplicate to copy an existing campaign, plus the instruction to offer dry_run=true first. It does not contrast with snapchat_launch_campaign, which is the nearest ambiguous alternative, so the when-not case is left implicit.

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