Sight Selftest

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

With no annotations, the description carries the burden well: it discloses the side effect ('Loads the model if it isn't already') and enumerates the returned check structure. It does not mention cost, duration, or failure modes when checks fail, keeping it short of full transparency.

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 the action and the rationale, and every sentence adds information about scope, side effects, or output. The trailing return-value sentence slightly duplicates the existing output schema, which is the only waste.

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 zero-parameter diagnostic with an output schema, the description covers what it does, why it exists, and the model-loading side effect. It could be more complete by stating what a failed test implies or recommending a follow-up action, but nothing essential is missing.

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 tool takes zero parameters, so the baseline of 4 applies; there is nothing for the description to disambiguate.

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 and resource — run a self-test that describes bundled reference images and validates the outputs — and clarifies the goal ('proves the install loaded correctly'). It is clearly distinguishable from describe_image/describe_batch, though it never names those siblings directly.

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?

Usage is implied by 'proves the install loaded correctly', which suggests running it as a post-install verification, and it notes the side effect of loading the model. However, it does not tell the agent when to prefer this over the sibling sight_status or when not to run it.

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