Things App MCP

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

Annotations already declare readOnlyHint=true, so the agent knows this is a safe read operation. The description adds useful context about platform dependency ('macOS only') and implementation detail ('Uses AppleScript'), which aren't covered by annotations. However, it doesn't describe return format, pagination, or error behavior.

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 with two sentences that each earn their place: the first states the core functionality, the second adds critical platform/implementation context. No wasted words, perfectly front-loaded.

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 simple read-only tool with no parameters and good annotations, the description is adequate but has gaps. It doesn't explain what 'tags' are in the Things context or describe the return format (especially important since there's no output schema). The macOS limitation is helpful 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 0 parameters and 100% schema description coverage, the baseline is 4. The description appropriately doesn't discuss parameters since none exist, and it adds value by explaining the tool's scope ('all tags') and platform constraints.

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 verb 'Get' and resource 'all tags from Things', making the purpose specific and understandable. However, it doesn't explicitly differentiate from sibling tools like 'get-areas' or 'get-projects', which also retrieve specific data types from the same system.

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 'search-todos' or 'get-todos', nor does it mention prerequisites such as macOS requirement beyond the AppleScript note. It lacks explicit when/when-not usage instructions.

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