Things MCP

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

Annotations include 'openWorldHint: true', which suggests flexibility, but the description adds useful behavioral context: it discloses that the tool supports both creation and updates, requires an auth-token for updates, and handles nested structures. However, it doesn't mention potential side effects, error handling, or rate limits, leaving some behavioral aspects unclear.

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 appropriately sized and front-loaded, starting with the core purpose. Sentences are efficient, but the last sentence could be more concise by combining update instructions. Overall, it avoids redundancy and each sentence adds value, though minor improvements in flow are possible.

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?

Given the tool's complexity (handling creation and updates of nested structures) and lack of output schema, the description is moderately complete. It covers key usage aspects but doesn't explain return values or error cases. With annotations providing some context and schema covering parameters, it meets basic needs but could benefit from more detail on outcomes.

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%, so the schema fully documents parameters. The description adds minimal semantics beyond the schema: it reiterates that 'data' should be an array with 'type' and 'attributes', and notes auth-token is required for updates. This provides slight clarification but doesn't significantly enhance understanding beyond the schema's detailed descriptions.

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 tool's purpose: 'Create complex projects and to-dos using the Things JSON command. Supports nested projects with headings, checklist items, and to-dos.' It specifies the verb ('create'), resource ('projects and to-dos'), and distinguishes from siblings like 'add-project' or 'add-todo' by emphasizing JSON-based creation with complex nested structures.

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 clear context for usage: 'For updates, include "operation": "update" and "id" fields, and provide auth-token.' This indicates when to use this tool for updates versus creation, though it doesn't explicitly name alternatives like 'update-project' or 'update-todo' for updates, nor does it specify when to use this over simpler sibling tools like 'add-project' for basic operations.

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