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

Annotations cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true), so the description is not obliged to repeat it. It does add a genuinely important behavioral fact the annotations do not carry: the campaign is always created in PAUSED state, meaning no immediate spend. It omits failure/partial-creation behavior and authorization requirements, 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?

All content sits in one dense but front-loaded sentence that leads with the creation scope before enumerating constraints. No filler, though the parenthetical stacking of limits makes it scannable only on a second read.

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?

This is a 19-parameter, 10-required multi-entity mutation with no output schema, so the description carries a lot of weight. It covers the creative and targeting fields well, but leaves out how location and audience IDs are obtained, the interaction between bidding and target_cpa/max_cpc, and what is returned on success or partial failure.

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 only 11% across 19 parameters, so the description has to compensate and largely does: character limits for headlines (≤30) and long headline/descriptions (≤90), minimum counts (1–5 headlines, ≥1 landscape 1.91:1, ≥1 square 1:1), https URL format for images, and the meaning of the audience segment ID fields. Gaps remain for account, dry_run, max_cpc, and the coupling of target_cpa to TARGET_CPA bidding.

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 gives a specific verb plus the full resource bundle created: 'Create a Display campaign with one ad group and a responsive display ad'. That scoping distinguishes it cleanly from google_ads_create_search_campaign, google_ads_create_pmax_campaign, and google_ads_add_display_ad without needing to name them.

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?

Usage is only implied: 'Always PAUSED' hints that google_ads_enable_campaign is the follow-up step, and the sibling set implies display-specific creation. There is no explicit when-to-use vs. when-not guidance, no mention of prerequisites such as account access, and no routing to google_ads_find_locations or google_ads_find_audiences for the ID-based fields.

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