Get asset image

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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description reinforces "Read-only" while adding the return modality (MCP ImageContent) that annotations cannot express. It also discloses the size/quality trade-off (250px fast vs 1440px higher quality). It stops short of error behavior for invalid asset_id or unsupported size, so not a 5.

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?

Front-loaded with purpose and then the disambiguation, followed by compact Args/Returns sections. Slightly long for two parameters and the Args block partly restates schema fields, but every sentence contributes routing or format 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?

For a simple two-parameter read tool with no output schema, the description covers purpose, alternative routing, parameter meaning, and return type (ImageContent), which is everything an agent needs to call it correctly. Remaining gaps are edge-case error handling only.

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 0%, so the description must carry both parameters — and it does: asset_id is identified as a UUID and size is given concrete meaning (250px fast vs 1440px higher quality, default thumbnail), values absent from the schema. It adds no validation guidance (allowed values, failure mode on an unknown size), which keeps it below a 5.

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?

States a specific verb and resource ("Get a single asset's thumbnail") plus the output form (image block for inline display). It explicitly names the sibling get_asset_thumbnail as the JSON alternative, so an agent can distinguish the two without opening either schema.

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?

Gives both when-to-use (image-rendering clients: Open WebUI, Claude Desktop) and when-to-use-the-alternative (HTML gallery / base64 data URIs / Cowork skills → get_asset_thumbnail). This is an explicit routing rule, not an implication.

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