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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered. The description's added value is the return shape: each rule carries its window, its suggestion, and a live count of unreviewed rows. That is genuinely useful since there is no output schema, but ordering, whether ended rules appear by default, and what 'suggestion' means operationally are left unstated.

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?

A single sentence with no filler, and the resource identification comes first. The trailing clause ('how many unreviewed rows it is suggesting for right now') is slightly clunky but carries real information rather than padding.

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 read-only, single-optional-parameter list tool this is close to adequate, and the description partially compensates for the absent output schema by describing the returned fields. Still missing: whether ended rules are excluded by default, result ordering, and any pointer to the suggestion-review workflow that the tool's output feeds.

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 one optional parameter, include_ended, and schema description coverage is 100%, so the schema fully documents it. The description never mentions the parameter or the default behavior around ended rules, so it adds nothing here — the baseline 3 for high coverage applies.

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 identifies the resource as 'rules the person set ahead of time' and even sketches the returned fields, so the subject matter is clear. However, it never states an explicit verb (list/retrieve) and gives no signal distinguishing it from siblings like purch_get_rule, purch_add_rule, or purch_end_rule, leaving the agent to infer this is the collection lister.

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 guidance on when to call this versus purch_get_rule (single rule), purch_add_rule (create), purch_end_rule (retire), or purch_accept_suggestions (act on the suggestions this tool reports). The 'unreviewed rows it is suggesting' phrase hints at a downstream workflow but never names the follow-up tool or the condition that triggers it.

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