unphurl-mcp

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 and does so comprehensively. It explains the verification requirement (email must be verified before API key works), time constraints (24-hour expiration), free credits allocation (20 pipeline check credits), what's always free (known/cached domains), and configuration requirements (adding API key to MCP server).

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 well-structured and front-loaded with the core purpose, followed by important behavioral details. While comprehensive, it could be slightly more concise - some information about free credits and known domains, while useful, might be trimmed. Most sentences earn their place by providing critical operational context.

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 tool with no annotations and no output schema, the description provides exceptional completeness. It covers the return value (API key), post-creation requirements (email verification), time constraints, free credits, what operations require credits, configuration steps, and relationships to other tools. This gives the agent everything needed to use this tool effectively.

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 100%, so the schema already documents all parameters thoroughly. The description doesn't add any meaningful parameter semantics beyond what's in the schema (email format, first name usage, company optionality). This meets the baseline expectation when schema coverage is complete.

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 a new Unphurl account') and resource ('account'), distinguishing it from sibling tools like 'create_profile' which likely manages user profiles rather than account creation. It goes beyond just restating the name by specifying what the tool actually accomplishes.

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 explicit guidance on when to use this tool (for initial account creation) and when to use alternatives: use 'resend_verification' if verification link expires, and use 'purchase' tool for buying credits. It also clarifies this tool doesn't require an API key, unlike other tools that do.

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