Things App MCP

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

The description adds valuable behavioral context beyond the annotations. While annotations only provide 'openWorldHint: true', the description discloses that the tool requires authentication ('Requires the to-do ID and your Things auth-token'), which is crucial operational information not captured in annotations. It also clarifies the scope of updates ('Supports changing title, notes, dates...'), helping the agent understand what modifications are possible.

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 perfectly concise and front-loaded. The first sentence establishes the core purpose and requirements, while the second efficiently enumerates the supported update fields. Every word earns its place with zero redundancy or unnecessary elaboration, making it easy for an agent to quickly understand the tool's capabilities.

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 complex mutation tool with 23 parameters and no output schema, the description provides good contextual coverage. It clearly states authentication requirements, identifies the resource being modified, and outlines the scope of possible updates. The main gap is the lack of information about return values or error conditions, which would be helpful given the absence of an output schema. However, the description adequately covers the essential operational context.

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?

With 100% schema description coverage, the input schema already documents all 23 parameters thoroughly. The description adds minimal parameter semantics by listing categories of updatable fields ('title, notes, dates, tags, checklist, list assignment, and status'), but this mostly restates what's already evident from the schema. The baseline score of 3 is appropriate since the schema does the heavy lifting.

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 ('Update an existing to-do in Things') and resource ('to-do'), distinguishing it from sibling tools like 'add-todo' (creation) and 'update-project' (different resource). It specifies the exact scope of what can be updated (title, notes, dates, tags, etc.), making the purpose unambiguous.

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 context by stating it's for updating existing to-dos and listing the supported fields, but doesn't explicitly state when to use this versus alternatives like 'add-todo' or 'update-project'. It mentions the required parameters (to-do ID and auth-token) which provides some usage prerequisites, but lacks explicit guidance on tool selection scenarios.

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