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

Annotations already declare readOnlyHint=true, destructiveHint=false and idempotentHint=true, so 'Changes nothing' mostly restates structured data. The description does add something beyond annotations by sketching what comes back (totals plus decision pages with a plain-language reason and the case), but it omits pagination mechanics and page-size behavior.

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 sentences, front-loaded with the core purpose and the returned data, closed with a short safety caveat. The middle is a dense comma list, but every clause carries content.

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 has to convey return shape and does so at a high level, which is genuinely useful. It stops short of explaining cursor paging (before / nextBefore), relative page sizes, or how filters combine, which an agent needs to use this 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 83%, so the schema already explains days, rule, route, stage and before. The description only repeats the 7/30/90 window and gestures at paging ('pages of decisions', 'nextBefore'), adding no format or edge-case detail beyond the field docs. Baseline 3 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 gives a specific verb ('Read') and a concrete resource (router decisions), and enumerates the two output shapes: aggregates by outcome/day/rule and paged decision records. It is clearly distinguishable in scope from the sibling rules-config tools (summer_router_rules_read, _history, _update), though it never names those siblings explicitly.

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 pick this tool over summer_router_rules_read, _history or _test, and no prerequisites or exclusions. The only guidance-adjacent line, 'Changes nothing', describes safety rather than selection conditions.

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