HubSpot 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 states the action ('Subscribe') which implies a write/mutation operation, but doesn't mention any behavioral traits like permission requirements, whether this is reversible (though 'communications_unsubscribe_contact' exists as a sibling), rate limits, or what happens on success/failure. This leaves significant gaps for an agent to understand the tool's behavior.

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 a single, clear sentence that states exactly what the tool does without any unnecessary words. It's perfectly front-loaded with the core functionality and wastes no space on redundant information.

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 mutation tool with 3 parameters (including complex legal basis parameters with enums), 0% schema description coverage, no annotations, and no output schema, the description is inadequate. It doesn't explain the legal basis parameters, doesn't mention behavioral aspects like permissions or side effects, and doesn't clarify the relationship with sibling subscription tools.

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 none of the 3 parameters are documented in the schema. The description mentions 'contact' which loosely relates to 'contactId', but provides no information about the two legal basis parameters or their significance. This fails to compensate for the complete lack of schema documentation.

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 action ('Subscribe') and resource ('a contact to all email communications'), making the purpose immediately understandable. However, it doesn't explicitly differentiate from sibling tools like 'communications_update_preferences' or 'communications_update_subscription_status', which might handle similar subscription-related operations.

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 provides no guidance on when to use this tool versus alternatives. There are multiple sibling tools related to communications and subscriptions (e.g., 'communications_update_preferences', 'communications_update_subscription_status'), but the description doesn't explain how this tool differs or when it should be preferred over them.

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