按项目聚合会话

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description usefully discloses the aggregation output (running/unread counts, last activity), but says nothing about ordering, pagination, or whether projects with zero sessions are excluded.

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 compact sentences: the first states the aggregation and its output fields, the second states the intended use. Nothing is redundant, and the core purpose 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?

There is no output schema, so the description correctly compensates by enumerating the aggregated fields returned. Combined with annotations covering read-only safety and a fully documented 2-parameter schema, the definition is nearly sufficient; only ordering/pagination and edge-case behavior remain unstated.

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 100%, so limit and min_sessions are already fully documented in the schema, including their defaults. The description adds no format, ordering, or interaction detail beyond that, so the 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 names a specific verb+resource (aggregate pi-web sessions by project directory) and enumerates exactly what is aggregated: session count, running count, unread count, last activity time. This clearly separates it from piweb_list_sessions, which lists sessions rather than grouping them, though no sibling is named 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?

The phrase 「用来先看『我的活儿都压在哪个目录』」 implies an exploratory/overview use case, which gives the agent some routing signal. However, it offers no explicit when-to-use conditions, no when-not, and does not point to alternatives such as piweb_list_sessions or piweb_list_unread for narrower questions.

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