Things MCP

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

Annotations provide readOnlyHint=true, and the description doesn't contradict this. It adds valuable context beyond annotations: the 'Uses AppleScript (macOS only)' disclosure about implementation and platform dependency, which isn't captured in annotations. However, it lacks details on rate limits, auth needs, or return 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 two sentences, front-loaded with the core purpose, followed by critical constraints. Every word earns its place: no fluff, clear and efficient structure.

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 moderate complexity (4 parameters, no output schema), the description is fairly complete. It covers purpose, usage rules, and platform constraints. However, without output schema, it doesn't describe return values or pagination, leaving a minor gap for a retrieval tool.

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., 'list' includes enum-like values). The description adds minimal semantics by mentioning the source types but doesn't provide extra syntax or format details beyond the schema. Baseline 3 is appropriate given high schema coverage.

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 ('to-dos from Things'), specifies the filtering options ('by list, project, area, or tag'), and distinguishes from siblings like 'get-recent-todos' or 'search-todos' by emphasizing exact source specification. It's specific and differentiated.

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 explicitly states 'Specify exactly one source', providing clear usage rules. It implies when not to use alternatives by focusing on filtered retrieval rather than search or recent items, and the platform constraint ('macOS only') adds context for exclusion.

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