ChartMogul MCP Server

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

No annotations are provided, so the description carries full burden. It mentions the tool updates existing events and returns the updated object, but lacks details on permissions, error handling, rate limits, or whether changes are reversible. For a mutation tool with zero annotation coverage, this is insufficient.

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 front-loaded with the core purpose, followed by usage hints and return information in three concise sentences. It avoids unnecessary repetition, though it could be slightly more structured for clarity.

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 no annotations, 0% schema coverage, no output schema, and nested parameters, the description is incomplete. It lacks details on behavioral traits, full parameter documentation, error cases, and output structure, leaving significant gaps for an AI agent.

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 0%, with 1 parameter ('data') documented only as an object with no properties. The description adds value by specifying 'subscription_event object with fields to update' and examples like 'effective_date', but does not fully compensate for the schema gap or provide detailed parameter semantics.

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 ('Update existing subscription event') and resource ('for Custom API data sources'), with specific examples of common updates. It distinguishes from siblings like 'create_subscription_event' by specifying 'existing' and from 'list_subscription_events' by focusing on modification rather than listing.

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 implies usage for updating subscription events in Custom API data sources, with examples of common fields. However, it lacks explicit guidance on when to use this tool versus alternatives like 'update_customer' or 'update_plan', and does not mention prerequisites or exclusions.

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