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

Goes well beyond the annotations by disclosing that the campaign is ALWAYS created paused and cannot spend until later steps, that names must be unique in the account, and that budgets above 50/day require allowLargeChange. The MaxConversions prerequisite (UET tag, conversion goal, volume) is operational context no annotation carries.

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?

Five front-loaded sentences, each carrying a distinct constraint or routing hint, with the paused-by-default fact placed early where it matters most. A little of the wording duplicates schema content (uniqueness, bid strategy list), which is the only 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?

For a 10-parameter mutation tool with no output schema, the description covers the full creation workflow, budget sourcing, spend implications, and dryRun verification, which is what an agent needs to call it correctly. It stops short of saying what identifier is returned on success, the one remaining 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?

Schema coverage is 100%, so the baseline is 3; the description adds genuine meaning by framing dailyBudget vs sharedBudgetId as a mutually exclusive choice, explaining the time zone fallback, and giving trade-off guidance on the three bid strategies rather than just repeating the enum. Minor repetition of the name-uniqueness rule already in the schema keeps it from a 5.

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 search campaign') and immediately identifies the Microsoft Advertising platform via the title and the msads_* siblings referenced. It is cleanly distinguishable from msads_create_ad_group, msads_create_shared_budget, and generic create_campaign.

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?

Explicitly routes the agent: budget comes either from dailyBudget or a sharedBudgetId obtained via msads_get_budgets, and activation happens later through msads_set_status after ad group, keywords and ad exist. It also names when a shared budget is preferable and when MaxConversions is appropriate (needs UET tag + conversion goal, 30+ conversions/month).

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