tally

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

No annotations are supplied, so the description carries the full behavioral burden. It does disclose real traits: aggregation by store tag, a count per group, and busiest-first ordering — enough to tell the agent this is a read-only aggregate rather than a mutation. However, it never states whether stores with zero open items appear, whether the data is live or cached, or that it is strictly non-mutating, which are the gaps an annotation would normally cover.

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: the first front-loads the literal output contract, the second supplies the usage motive. Neither sentence is filler, and the parenthetical ordering note is compact rather than restated in prose.

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 zero-argument read tool with an output schema present, the description covers purpose, output shape, ordering, and usage context — return-value details are correctly delegated to the output schema. The only shortfall is unstated handling of empty or zero-count store groups, a small ambiguity for an aggregation tool.

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 no parameter semantics to explain and the baseline of 4 applies. The description correctly implies there are no filters or scope arguments — the entire open list is always aggregated.

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?

"Show the open list grouped by store tag, with a count per store (busiest first)" names a specific verb (show), a specific resource (open list), and the exact output shape (grouped counts, descending order). That distinguishes it from a flat item listing such as list_items or a scheduling action such as plan_run without needing either schema.

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?

The second sentence positions it as "the quick 'how long is each store's list' view before planning a run," which gives a concrete when-to-use context and implicitly routes the agent to plan_run as the next step. It stops short of explicit exclusions (e.g., don't use this when you need per-item detail), so it lands just below the top band.

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