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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), yet the description adds genuinely new behavior: it needs no key, takes no input, reads no photo, and spends nothing. Auth requirements and cost are exactly the traits annotations do not carry, so this adds real value.

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 imperative 'Use this FIRST', then the conditions, then the return behavior, then the guardrail against misuse. Every sentence earns its place with no filler.

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 no-input tool with an output schema and rich annotations, the description covers the remaining gaps: what is returned (a real stored sample labelled SAMPLE plus key instructions), that it is free and reads nothing, and how it differs from the real assessment path. Nothing needed to call it correctly 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?

Zero parameters, so the baseline is 4. The description reinforces this with 'takes no input', consistent with the empty schema and additionalProperties=false, leaving nothing ambiguous.

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?

States a specific verb (try/return) and resource (a stored sample fixRAgent assessment) and explicitly names what it is not, routing to the sibling 'assess_property_photo with a key' for real photos. An agent can distinguish it from both siblings without opening any schema.

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?

Gives explicit triggering conditions ('Use this FIRST when the person has just connected fixRAgent, has no key yet, or asks what fixRAgent does') and a clear exclusion ('Do not present the sample as an assessment of the person's own photo; for their photo, use assess_property_photo with a key'). When-to-use, when-not, and the alternative are all present.

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