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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds a genuinely new behavioral fact the annotations do not carry: that reads are free and incur no credit charge, which is decision-relevant for a credit-metered platform.

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 short sentences with no filler. The field inventory is stated first and the cost caveat second, so the highest-value information is front-loaded.

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 parameters, full annotation coverage, and an output schema handling return values, the description covers what an agent needs to select and call this tool. Minor ambiguity remains around whether "access state" and "role" describe the caller or a broader account, but the output schema fills that gap.

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 there is nothing for the description to disambiguate; the baseline applies. The enumerated output fields are a bonus rather than a necessity given the input schema is empty.

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 uses a specific verb ("Show") against a clearly scoped resource: the caller's access state, role, UTC term, and credit counters. That inventory of fields lets an agent distinguish it from the task/report siblings at a glance, though it never explicitly names a contrasting tool such as research_info.

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?

"Reads cost no credits" implicitly frames this as the cheap way to check account state, which is useful decision input, but the description never says when to call it versus alternatives or states any prerequisite. Usage is inferred rather than directed.

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