Date-time Tools MCP

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

With no annotations provided, the description carries full burden. It discloses the required date format (luxon format) and provides concrete examples, which is valuable. However, it doesn't mention error handling, whether the operation is reversible, or what happens with invalid inputs. The description adds context about format requirements but lacks comprehensive behavioral details.

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 with three bullet points that each serve distinct purposes: purpose statement, format requirements, and usage prerequisites. It's front-loaded with the core functionality. Minor improvement could be made by combining some format details, but overall it's efficient.

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 (date manipulation with format constraints), no annotations, and no output schema, the description does well by covering format requirements, examples, and workflow dependencies. It could be more complete by mentioning return format or error cases, but it provides sufficient context for basic usage.

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 baseline is 3. The description adds value by providing concrete examples of both parameters (date format example and update object example), which enhances understanding beyond the schema's technical definitions. However, it doesn't explain edge cases or parameter interactions.

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 with specific verb ('mutates') and resource ('date time string'), and distinguishes it from sibling tools by focusing on date manipulation rather than timezone conversion or current date retrieval. It specifies the exact operations (adding/subtracting days, hours, minutes, months, years).

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 explicit guidance on when to use this tool versus alternatives: it instructs to first invoke 'currentDateTimeAndTimezone' when users don't specify absolute dates (e.g., 'today', 'tomorrow'), creating clear workflow dependencies. This directly addresses when to use this tool versus the sibling tool.

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