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 the implementation method ('Uses AppleScript') and platform limitation ('macOS only'), which aren't covered by annotations. However, it doesn't describe behavioral aspects like return format, pagination, or error handling.

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 with two sentences that each add distinct value: the first states the core functionality, the second provides important implementation context. There's zero wasted language, and information is front-loaded appropriately.

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 operation with readOnlyHint annotation and no parameters, the description covers the basic purpose and platform constraints adequately. However, without an output schema, it doesn't describe what 'projects' data is returned (e.g., fields, structure), leaving the agent uncertain about the response format. The macOS limitation is important but doesn't fully compensate for the missing output information.

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 schema fully documents the absence of inputs. The description doesn't need to add parameter information, so it appropriately focuses on other aspects. A baseline of 4 is appropriate for zero-parameter tools when the schema coverage is complete.

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 projects') and resource ('from Things'), making the purpose immediately understandable. It distinguishes from siblings like 'get-project-by-id' by specifying 'all projects' rather than a single one. However, it doesn't explicitly differentiate from other list tools like 'get-areas' or 'get-todos' beyond the resource name.

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 when to choose 'get-projects' over 'get-project-by-id' for specific projects, or 'get-areas' for different resource types. The macOS-only note is a platform constraint, not usage guidance relative to sibling tools.

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