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

Annotations already declare readOnly, idempotent, non-destructive, open-world behavior, so the safety profile is covered. The description adds genuinely non-obvious context: the 'visual' tool returns no image pixels and receives no photograph, and needs no authentication, which prevents a real misuse pattern. It stops short of describing the returned text structure, but the output shape is partly signaled by 'public text-only ... reference and its canonical links'.

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, front-loaded with the core action. The clause pair 'returns no image pixels and receives no photograph' is slightly redundant, a minor waste in an otherwise tight definition.

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?

With no output schema and no parameters, the description carries the load and does so adequately: it states the source, the text-only nature, the returned links, and the auth posture. A sentence on the shape of the 'canonical links' payload would make it fully self-sufficient.

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 per the rubric the baseline is 4. There is nothing for the description to add on parameter semantics, and it introduces no ambiguity.

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?

Names a specific verb (read) and resource (Marbella 1985 visual reference + canonical links), and immediately narrows scope by stating it is text-only and image-free. The negative clauses distinguish it from image-oriented siblings, though it does not scope itself against the many other get_* tools.

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?

Explicitly routes the caller: 'Use put_me_inside_cassie_hour for a scene-specific text prompt for the caller's own image-capable assistant.' This names the alternative and the condition that selects it, so the agent can disambiguate without inference.

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