Things MCP

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

Annotations provide openWorldHint=true, indicating flexible input handling. The description adds valuable context beyond this: it discloses the tool 'Uses the Things URL scheme' (implementation detail affecting behavior) and lists specific supported fields, giving practical insight into what can be set. No contradiction with annotations.

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 front-loaded with the core purpose ('Create a new to-do in Things'), followed by a concise list of supported fields and a key implementation note. It avoids redundancy, though the list of fields is somewhat lengthy but necessary for clarity.

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 (17 parameters, no output schema) and rich schema coverage, the description is reasonably complete. It covers purpose, supported fields, and a behavioral note. However, it lacks details on error handling, response format, or interactions with sibling tools, leaving minor gaps.

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%, with each parameter well-documented in the schema (e.g., format for 'when', max lengths). The description adds no additional parameter semantics beyond listing field names, so it meets the baseline of 3 where 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 explicitly states 'Create a new to-do in Things' with a specific verb ('Create') and resource ('to-do'), clearly distinguishing it from sibling tools like 'update-todo' (modifies existing) or 'get-todos' (reads). It lists supported fields (title, notes, dates, tags, etc.) to further clarify scope.

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 for creating to-dos but doesn't explicitly state when to use this vs. alternatives like 'add-json' (for batch creation) or 'update-todo' (for modifications). No guidance on prerequisites (e.g., needing Things app) or exclusions is provided.

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