read_image

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

With no annotations, the description fully discloses behavior: images are not cached, every call re-reads from disk, a byte cap exists (default 5 MiB), and it returns an MCP image content block plus JSON metadata.

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 well-structured with a brief first sentence followed by technical details. While slightly verbose, each sentence adds value and the structure is easy to parse.

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 the simple input schema (1 parameter) and presence of output schema, the description covers all essential aspects: purpose, usage context, caching behavior, size limit, and path format. No gaps remain.

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?

The only parameter 'path' has no schema description (0% coverage), but the description adds that it is 'absolute or relative to project root', providing crucial context beyond the schema's type definition.

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 'Read an image file and pass the bytes through to the model', specifying the verb and resource. It distinguishes from the sibling 'read' tool by noting 'for any other file type use `read`.'

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?

Explicit guidance on when to use ('when the model needs to actually see the image') and when not ('for any other file type use `read`'). Also provides context on caching and size limits.

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