How long an agent has behaved the same way (free)

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), but the description adds substantive context: the metric is a CUSUM over payments/USD/payees, a break is a change not a harm, and the false-break rate is published. This is genuine behavioural disclosure beyond the structured fields.

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 primary measure is front-loaded, which is good, but the definition packs multiple nested parentheticals and jargon into a dense block. Every clause is informative, yet the run-on structure makes it heavier than it needs to be.

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 correctly compensates by enumerating the returned fields and their meaning (run_days, break date/feature, heartbeat classification with dispersion index and gap CV) and cites definition IDs. Only the absence of routing guidance to alternatives keeps it from being fully complete.

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?

There is a single parameter with 100% schema description coverage ('Agent token id, slug or bound wallet'), so the schema carries the semantics. The description adds nothing about the agent argument, making this baseline adequate rather than enriched.

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 names the resource concretely — the behaviour clock for one ranked agent — and enumerates the returned measures (run_days, last break date/feature, 30-day heartbeat). It is clear what the tool produces, though it does not explicitly contrast itself with siblings like agent_record or since_last.

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?

There is no statement of when to reach for this tool versus the many sibling metrics tools (agent_independence, since_last, metric_history). The reference to a published false-break rate hints at documentation but gives no usage conditions or exclusions.

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