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

Beyond the annotations, the description adds meaningful behavioral detail: it explains default asset behavior, the optional asset='body' selection, and that 'Images are bounded, resized, and compressed on demand.' Despite readOnlyHint=false, the text clearly indicates a non-destructive read operation, and the behavior does not contradict the annotations.

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 compact and front-loaded with the core purpose, then efficiently covers usage timing, constraints, defaults, and output behavior. Every sentence contributes uniquely and no redundant boilerplate is present.

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?

The tool has an output schema, fully described parameters, and relevant annotations, and the description fills in the remaining context: when to invoke it, what the returned content type is, and how assets are processed. An agent has everything needed to select and call this tool correctly.

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 coverage is 100%, so each parameter already has a clear description. The tool description adds modest value by explaining the default asset ('the note's stored source preview') and reinforcing that URL input is not accepted, but it largely relies on the schema for parameter meaning.

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 opens with a specific verb and resource: 'Return an image already associated with a stored note as native MCP image content.' It clearly differentiates this tool from text-only search/list siblings by noting that image retrieval is for visual inspection and that search/list responses remain text-only.

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 gives explicit guidance: 'Use this after search or list when visual inspection would help' and warns 'do not call it for every note.' It also clarifies a key constraint, 'It never accepts a URL,' which prevents a common misuse.

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