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

Goes well beyond readOnlyHint=false/openWorldHint=true: it discloses the resulting state of every created entity ("Everything is created PAUSED"), the side effect that attached files are uploaded and creatives generated, and the required human-confirmation gate before going live. It also clarifies override precedence for copy_from_campaign, which is a behavioral contract, not just a parameter name.

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 what gets built, then targeting options, then the preference rule and the dry-run workflow — a sensible order with no filler sentences. It is dense and parenthetical-heavy, but nearly every clause carries decision-relevant information.

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 27-parameter, no-output-schema orchestration tool this covers the essentials: what is created, default paused state, targeting shortcuts, copy semantics, and the two-phase dry-run protocol. Return values are implied by "show the plan," and with no output schema an agent mostly needs the call sequence and side-effect profile, both of which are present.

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 only 41% across 27 parameters, so the description does real work on the highest-risk ones: it enumerates the targeting dimensions (countries/ages/gender/os/audience segments), explains that ads drives one ad per item with media/creative reuse, and defines copy_from_campaign's scope plus override semantics. It does not add meaning for bid, bid_strategy, optimization_goal, daily_budget, account, profile_id or the time fields, leaving those to bare schema names and enums.

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 a decomposed resource set: "campaign + ad squad (goal, daily budget, bidding, targeting) + one ad per item in ads (uploads attached files, creates creatives)." An agent can immediately distinguish it from the granular siblings snapchat_create_campaign, snapchat_create_adsquad and snapchat_create_ad.

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 an explicit routing rule ("Prefer this over the step-by-step tools") and a mandatory operating procedure ("Always call with dry_run=true first, show the plan, then call again with dry_run=false after the user agrees"). It also names the follow-up path for going live ("turning it on later needs snapchat_set_status + confirmation") and spells out the two copy alternatives, including when copy_from_campaign is preferable ("no need to read its settings first").

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