Examplary MCP Server

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

With no annotations provided, the description carries full burden for behavioral disclosure. It mentions 'start processing it' which implies an asynchronous operation, but doesn't specify processing time, success/failure indicators, permissions required, or what 'processing' entails. For a creation tool with zero annotation coverage, this leaves significant behavioral gaps.

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 zero wasted words. It's appropriately sized for the tool's apparent complexity and front-loads the essential information.

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 7 parameters with minimal schema documentation (14% coverage), no annotations, and a creation operation, the description is incomplete. While an output schema exists (which reduces need to describe return values), the description doesn't address parameter meanings, processing behavior, or usage context sufficiently for this complex 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 only 14% (1 of 7 parameters has a description), so the description must compensate but doesn't. It mentions no parameters at all, leaving 7 parameters undocumented. The description fails to explain what 'url', 'type', 'name', 'size', 'contentType', 'expires', or 'externalId' mean in this context.

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 action ('Add a source material and start processing it') and purpose ('for later use in an exam'), providing a specific verb+resource combination. However, it doesn't explicitly distinguish this from sibling tools like 'postSource_materialsidSlice' or 'getSource_materials', which would be needed for a perfect score.

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 minimal guidance by mentioning the purpose ('for later use in an exam'), but offers no explicit when-to-use rules, no alternatives, and no prerequisites. It doesn't help the agent decide between this tool and related tools like 'postSource_materialsidSlice' or 'getSource_materials'.

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