Billing setup for one customer (ledger by default). No invoice retrieval.
| Name | Required | Description | Default |
|---|---|---|---|
| source | No | Read source; defaults to synced data ('ledger'). 'live' sweeps the API. | |
| customer_id | Yes | 10-digit Google Ads customer id. | |
| connection_context | No |
Changes observed during successful MCP inspections.
Input schema / properties / source / descriptionPrevious value: -"Read source; defaults to the Supabase ledger. 'live' sweeps the API."New value: +"Read source; defaults to synced data ('ledger'). 'live' sweeps the API."Input schema / properties / connection_contextAdded value: +{
+ "pattern": "^mctx_v1_[0-9a-f]{64}$",
+ "type": "string"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds real value by disclosing the default read source and explicitly bounding scope ('No invoice retrieval'), but it says nothing about what the returned setup contains or freshness/auth requirements beyond the ledger/live distinction.
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?
Two tight, front-loaded sentences with no filler. It is efficient, though the terse phrasing ('Billing setup for one customer') leans on the tool name to disambiguate that this is a 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?
For a read-only tool with annotations covering safety and no output schema, the description covers scope but not the shape of the returned billing setup. It is adequate but leaves a gap an agent would want filled given the missing output schema.
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 67%: customer_id and source are documented in the schema, while connection_context has only a pattern and no description. The description reinforces the source default but adds no syntax or meaning beyond the schema, so the baseline 3 fits.
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+resource: retrieving the billing setup for one customer. The parenthetical '(ledger by default)' and 'No invoice retrieval' sharpen scope, but no sibling tool is named for contrast, so it stops short of a 5.
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?
'No invoice retrieval' is a useful when-not exclusion, and the '(ledger by default)' note implies the synced-data read path. However, there is no explicit statement of when to call this versus other account/billing-adjacent tools, so usage is only implied.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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