CDP MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes a critical behavioral constraint ('standalone messageDefs created here CANNOT be referenced from a campaign by resourceId — the server rejects shared references with E0420'), which is essential for correct usage. However, it doesn't mention other potential behavioral aspects like permissions needed, rate limits, or whether the operation is idempotent.

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?

The description is efficiently structured with four sentences that each add value: stating the purpose, providing the parameter format, giving a critical warning with error details, and specifying the appropriate usage context. There's no wasted text, and the most important information (the warning) is prominently placed.

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?

Given that there's an output schema (which handles return values) but no annotations and 0% schema description coverage, the description does well on purpose and guidelines but falls short on parameter documentation. The critical behavioral warning compensates somewhat, making it mostly complete for safe usage but incomplete for parameter understanding.

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?

The schema description coverage is 0%, meaning parameters are completely undocumented in the schema. The description only vaguely mentions 'Pass as a JSON string list' without explaining what the 'body' parameter should contain or what format the JSON should have. It doesn't address the 'tenant_id' parameter at all, leaving significant gaps in parameter understanding.

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 clearly states the specific action ('Create standalone message definitions') and resource ('message definitions'), distinguishing it from the sibling tool 'cdp_update_campaign' by explicitly contrasting standalone vs. campaign-bound usage. It provides precise differentiation beyond just the verb and resource.

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?

The description explicitly defines when to use this tool ('for message templates that are independently managed') and when not to use it ('For campaign-bound emails, instead put the messageDef object INLINE in the campaign's 'messageDefs' array via cdp_update_campaign'), including a named alternative tool. It also provides a specific error code (E0420) that helps avoid misuse.

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