Habitica MCP Server

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states the action is a purchase but doesn't cover critical aspects like whether it deducts currency, requires authentication, has rate limits, or what happens on failure. This is a significant gap for a transactional tool.

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, efficient phrase with zero waste. It's appropriately sized and front-loaded, making it easy to parse quickly without unnecessary elaboration.

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 complexity of a purchase transaction with no annotations and no output schema, the description is incomplete. It lacks details on behavioral traits, return values, error handling, and how it integrates with sibling tools like 'get_shop' or 'get_inventory', leaving the agent under-informed.

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 both parameters ('itemKey' and 'quantity'). The description adds no additional meaning beyond what the schema provides, such as explaining what 'itemKey' refers to or valid quantity ranges, meeting the baseline for high coverage.

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 '购买商店物品' (buy store items) states a clear verb+resource action, indicating the tool purchases items from a store. However, it doesn't distinguish from sibling tools like 'buy_reward' or specify what types of items are available, leaving the purpose somewhat vague.

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. It doesn't mention prerequisites (e.g., having sufficient currency), exclusions, or how it differs from similar tools like 'buy_reward', leaving the agent with no usage context.

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