Things MCP

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

Annotations declare readOnlyHint=true, which the description aligns with by using 'Get' (a read operation). The description adds value by specifying the implementation method ('Uses AppleScript') and platform constraint ('macOS only'), which aren't covered by annotations. However, it doesn't detail behavioral aspects like performance, error handling, or output format.

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 short sentences that front-load the core purpose ('Get all tags from Things') and follow with implementation details. Every word earns its place, with no wasted text or 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?

For a simple read-only tool with 0 parameters and annotations covering safety, the description is adequate but minimal. It lacks output details (no schema provided) and doesn't explain the scope of 'all tags' (e.g., if filtered or paginated). The macOS constraint is helpful, but more context on behavior would improve completeness.

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 appropriately doesn't discuss parameters, maintaining focus on the tool's purpose and constraints without redundancy.

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 ('Get all tags') and resource ('from Things'), making the purpose understandable. It distinguishes from some siblings like 'add-todo' or 'update-project' by focusing on retrieval, but doesn't explicitly differentiate from other get operations like 'get-areas' or 'get-projects' beyond the resource type.

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 mentions 'macOS only' as a platform constraint, but doesn't explain when to choose this over other tag-related operations (none exist in siblings) or other retrieval tools like 'get-areas' or 'get-projects' for different data types.

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