Read an image source

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

Adds beyond annotations by specifying supported image formats and that provenance is included. Annotations already indicate read-only, open-world, idempotent, non-destructive behavior; description complements with format and provenance details.

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?

Two sentences, no redundant words. Core function in first sentence, critical usage condition in second. Perfectly front-loaded.

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 tool with one parameter and no output schema, description covers purpose, parameter, formats, provenance, and prerequisite. Sibling tools exist but could be contrasted more. Still fairly complete.

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?

Describes source as 'allowed local path or public URL', which adds meaning beyond the schema's plain string definition. However, 'allowed' is vague and no examples are given. With 0% schema coverage, the description compensates partially.

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?

Description clearly states the tool returns an image (PNG, JPEG, GIF, WebP) from a local path or public URL with provenance. This distinguishes it from siblings like read_web_source which likely return non-image content.

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?

Mentions that the AI must support image content to interpret the result, providing a usage condition. Does not explicitly exclude alternatives or mention when not to use, but the context is clear enough.

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