Katzilla MCP

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

Annotations already cover read-only, non-destructive, idempotent, and open-world hints, so the description adds valuable context beyond these. It discloses that the tool 'updates real-time' (indicating freshness), describes the return format ('Katzilla envelope { data, quality, citation }'), and explains quality metrics ('freshness/uptime/confidence') and citation details ('source URL, license, and a SHA-256 data hash for audit'). This enriches behavioral understanding without contradicting annotations.

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 in the first sentence, followed by source and update frequency, and then details on the return format. Every sentence adds essential information without redundancy, making it efficient and well-structured for quick understanding.

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 the tool's simplicity (0 parameters, annotations covering safety and behavior, and an output schema implied by the description), the description is complete. It explains what the tool does, its source, update frequency, and return format with quality and citation details, providing all necessary context for an agent to use it effectively without gaps.

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 input schema has 0 parameters with 100% coverage, so no parameter documentation is needed. The description does not mention any parameters, which is appropriate. It adds value by explaining the output structure and data sources, compensating for the lack of input complexity. Baseline is 3 for high schema coverage, but the description's output details elevate it slightly.

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 explicitly states the tool's purpose: 'Get the current ETH price in USD and BTC from Etherscan.' It specifies the verb ('Get'), resource ('current ETH price'), and distinguishes it from sibling tools like 'crypto__etherscan-balance' or 'crypto__etherscan-gas' by focusing on price data rather than balances, gas fees, or transactions.

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 clear context for usage: 'Source: Etherscan (Etherscan Terms), updates real-time.' This indicates when to use it (for real-time ETH price data from Etherscan) and implies it's for cryptocurrency price queries. However, it does not explicitly state when not to use it or name alternatives among siblings, such as 'crypto__coinpaprika' for other crypto prices.

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