Read Image

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

Annotations already declare the operation is read-only and non-destructive, so the bar is lower. The description adds valuable behavioral context beyond the annotations: default preview sizing of 1600 px, the experimental nature of values above 1600 in ChatGPT, and the guarantee of returning native MCP image content. It does not fully describe failure behavior or output-size edge cases, but the schema covers those partially.

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 uses only three sentences, each earning its place: purpose, sizing behavior, and alternative routing. It front-loads the core purpose and avoids redundant restatement of the tool name or schema details.

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 read-only preview tool with fully documented parameters and annotations, the description is complete. It clarifies the output type (native MCP image content), supported formats, preview sizing limits, and the available sibling tools for pixel-level work. No output schema exists, but the description sufficiently covers what the agent needs to know.

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 100%, so the schema already documents path, workspace_id, max_dimension, and return_original with detailed constraints. The description adds no new parameter-specific meaning beyond what the schema provides, so the baseline of 3 applies.

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 states a specific verb-resource pair: 'Read a workspace-local JPEG, PNG, or WebP as native MCP image content.' It clearly differentiates from the closely related siblings image_info, read_image_crop, and read_image_tile by naming them as alternatives for pixel-level detail rather than whole-image previews.

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 explicitly tells the agent when not to use this tool: 'For pixel-level detail, prefer image_info plus read_image_crop/read_image_tile.' It also implies the correct use case through 'Safe default previews' and the mention of returning native MCP image content. This is explicit enough for an agent to route correctly.

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