Pre-flight check campaign rows BEFORE creating. Read-only. Per-row verdict: will_create / will_create_with_changes / will_fail. Pass meta_account_id to also check spend guardrails.
| Name | Required | Description | Default |
|---|---|---|---|
| campaigns | Yes | ||
| meta_account_id | No |
Changes observed during successful MCP inspections.
Input schema / properties / campaigns / items / properties / geoLocationsAdded value: +{
+ "additionalProperties": true,
+ "description": "OPTIONAL specific places instead of whole countries (replaces countries when set). Get keys from search_locations. cities: [{ key, radius (km, 17-80; omit for the city only), country_code }], regions: [{ key, country_code }] (states), zips: [{ key e.g. \"IN:380015\", country_code }] (PIN/ZIP codes). Meta rejects overlapping places (e.g. a PIN inside a city radius). With a Special Ad Category: no zips, and cities need a radius of at least 25 km.",
+ "properties": {
+ "cities": {
+ "items": {
+ "properties": {
+ "country_code": {
+ "type": "string"
+ },
+ "key": {
+ "type": "string"
+ },
+ "radius": {
+ "type": "number"
+ }
+ },
+ "required": [
+ "key"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ },
+ "regions": {
+ "items": {
+ "properties": {
+ "country_code": {
+ "type": "string"
+ },
+ "key": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "key"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ },
+ "zips": {
+ "items": {
+ "properties": {
+ "country_code": {
+ "type": "string"
+ },
+ "key": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "key"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ }
+ },
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
readOnlyHint=true already covers the safety profile, so the 'Read-only' sentence is redundant. The description does add real behavioral context: the three per-row verdict outcomes and the fact that meta_account_id extends the check to spend guardrails. It omits what happens on malformed rows or how expensive the check is.
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?
Telegraphic and front-loaded: purpose, safety, output categories, optional parameter, in that order. The single 'Read-only' sentence duplicates the readOnlyHint annotation and earns little.
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 two-parameter dry-run tool with no output schema, the description supplies the essential return semantics (verdict categories) and the guardrail-check flag. Missing only edge-case behavior, such as how invalid rows are reported or whether all rows are evaluated before returning.
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?
No output schema exists and top-level parameters carry no schema descriptions, so the description must compensate. It does explain meta_account_id's effect (guardrail checks), which the schema leaves blank, but says nothing about the campaigns array beyond 'campaign rows' at the top level, relying entirely on the richly described nested properties.
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 (pre-flight check) and resource (campaign rows) plus the timing constraint 'BEFORE creating', which implicitly separates it from create_campaign and bulk_create_campaigns. It never names a sibling explicitly, so an agent must infer the routing itself.
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 context for use ('BEFORE creating') and a conditional enhancement ('Pass meta_account_id to also check spend guardrails'). It stops short of naming alternatives such as create_campaign or bulk_create_campaigns or stating when validation is unnecessary.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.