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

Beyond the readOnly/openWorld annotations, the description discloses pricing and metering behavior (US$0.001 per answer, first 100/month free) and the important edge case that unanswered questions are never metered. It also clarifies the returned figure is a published observation, not an estimate, forecast or advice.

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 core purpose is front-loaded and each sentence carries distinct information (what it returns, what the figure is not, rate/metering, unanswered-question rule). Dense but with no obvious filler; the pricing detail is the only part that could be trimmed.

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, the description carries the return-value burden and does so by listing the components of an answer (figure, both clocks, source, receipt, scope). Combined with the metering and unanswered-question rules, it is complete enough for an agent to call it 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 description coverage is 100%, so the two required parameters (subject_key, attribute) are already fully documented in the schema. The description's framing (one attribute of one subject) reinforces this but adds no syntax or format beyond the schema, making the baseline 3 appropriate.

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+resource: answering one question (the newest observed value of one attribute of one subject) from oddly's record, and enumerates what comes back (figure, both clocks, source, receipt, scope). It is unambiguous what the tool does, though it never names a sibling to differentiate from (e.g. record_subject_history) 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 rather than stated: the tool answers a specific point-in-time value, and the metering/unanswered-question notes hint at when it is and isn't appropriate. There is no explicit when-to-use versus alternatives such as record_subject_history or record_verify_receipt.

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