Happy Server MCP

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. 'Delete' implies a destructive mutation, but the description doesn't specify whether deletion is permanent, reversible, requires specific permissions, or what happens on success/failure. For a destructive operation with zero annotation coverage, this leaves significant behavioral gaps.

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 extremely concise - a single sentence that directly states the tool's purpose with zero wasted words. It's appropriately sized for a simple delete operation and front-loads the essential 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 destructive operation with no annotations and no output schema, the description is insufficient. It doesn't explain what happens after deletion (success confirmation, error cases), doesn't mention permissions or side effects, and provides no context about the todo system. Given the complexity of a delete operation, more completeness is needed.

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% (the 'id' parameter is fully documented in the schema), so the baseline is 3. The description doesn't add any parameter-specific information beyond what's already in the schema - it doesn't explain where to find the todo ID, format requirements, or provide examples.

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 ('Delete') and resource ('a Zen (todo) item'), making the purpose immediately understandable. However, it doesn't differentiate this tool from its sibling 'happy_zen_update_todo' or 'happy_zen_set_todo_done' which might also modify todo items, so it doesn't fully distinguish from alternatives.

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 like 'happy_zen_update_todo' or 'happy_zen_set_todo_done'. It doesn't mention prerequisites (e.g., needing an existing todo ID) or when deletion is appropriate versus updating status. No explicit when/when-not statements are present.

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