Amazing Marvin MCP

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

With no annotations provided, the description carries full burden but offers minimal behavioral context. It doesn't disclose what happens when no item is being tracked (returns null/empty/error), whether this requires authentication, or any rate limits. The mention of 'Amazing Marvin' provides some system context but not operational behavior.

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 a single, efficient sentence that gets straight to the point with no wasted words. It's appropriately sized for a simple retrieval tool and front-loads the core purpose immediately.

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?

For a simple read operation with an output schema (which handles return values), the description is minimally adequate. However, with no annotations and behavioral gaps (what happens when nothing is tracked), it doesn't provide complete context for reliable agent use. The output schema helps but doesn't compensate for missing behavioral 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?

The tool has only one optional parameter ('debug') with 0% schema description coverage. The description doesn't mention parameters at all, which is acceptable for a tool with zero required parameters. The baseline for 0 required parameters is 4, as the agent can invoke this without understanding parameters.

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 ('currently tracked item') with the system context ('from Amazing Marvin'). It's specific about retrieving the single currently tracked item, but doesn't explicitly differentiate from sibling time tracking tools like 'start_time_tracking' or 'stop_time_tracking'.

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 no guidance on when to use this tool versus alternatives like 'get_time_tracks' or 'time_tracking_summary'. It doesn't indicate whether this is for active tracking sessions only or if it returns null when nothing is being tracked.

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