local_describe_image

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

With no annotations, the description fully carries the burden of behavioral disclosure. It states that the image is read server-side, never enters Claude's context, only text is returned, and the tool never generates or edits images. The guardrail on scope (image->text only) is clearly communicated.

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 separate sections for usage guidance, function, guardrail, and arguments. It is moderately long but every sentence adds value. Slight redundancy in the first paragraph could be trimmed, but overall it is clear and focused.

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 description covers purpose, usage, behavior, and parameters adequately. Although an output schema exists (not shown), the description mentions the response is text. Given three parameters and no annotations, the description is sufficiently complete for an agent to use the 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 0%, so the description must compensate, and it does. For `path`, it specifies the image format and server-side reading. For `question`, it notes optionality and guide for description. For `max_words`, it states maximum response length. This adds meaningful context beyond the schema's type and default values.

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 the tool's function: describing an image or answering a question about it using a local vision model. It distinguishes itself from alternatives by instructing the agent to prefer this tool over reading the image itself when only a description is needed. The verb+resource combination is specific and unambiguous.

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 advises when to use the tool—for description, OCR, or specific questions about an image, and not for including the image in context. It provides context about server-side reading and privacy. However, it does not explicitly mention when not to use it or compare it to sibling tools, which are all non-vision tools, so the differentiation is implicit.

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