Amazing Marvin MCP

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

No annotations are provided, so the description carries the full burden. It states the action ('Mark a task as completed') but lacks details on behavioral traits such as permissions required, whether the action is reversible, error handling, or rate limits. The mention of 'timezone_offset' hints at time-sensitive behavior but doesn't explain its impact. For a mutation tool with zero annotation coverage, this is a significant gap.

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: the first sentence states the purpose clearly, followed by a structured 'Args:' section for parameters, and ends with usage guidance. Every sentence adds value without redundancy, making it efficient and well-organized.

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 (3 parameters, mutation operation) and the presence of an output schema (which handles return values), the description is mostly complete. It covers purpose, parameters partially, and usage guidelines, but lacks behavioral details due to no annotations. For a tool with output schema, this is adequate but could be improved with more transparency.

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 0%, so the schema provides no parameter details. The description adds meaning for 'item_id' (Task ID to mark as done) and 'timezone_offset' (Timezone offset in minutes from UTC with an example), but omits 'debug' entirely. This partially compensates for the coverage gap but leaves one parameter undocumented, aligning with the baseline for incomplete compensation.

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 ('Mark') and resource ('a task as completed') with the system context ('in Amazing Marvin'), making the purpose specific and understandable. However, it doesn't explicitly differentiate from siblings like 'batch_mark_done' beyond mentioning it as an alternative for multiple tasks, which is covered more in usage guidelines.

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 vs. alternatives: it specifies 'For completing multiple tasks, use batch_mark_done(task_ids) instead.' This clearly defines the scope (single task completion) and names the alternative tool for batch operations, helping the agent choose correctly.

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