upc_session_status

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

Annotations already declare readOnly/non-destructive/openWorld, so the bar is lower, and the description still adds real value: it discloses that state is 'local' (not a live network verification), exposes a freshness signal ('last verified time'), and gives an explicit security guarantee ('never returns credentials'). What it omits is what state values exist and what triggers a re-verification.

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 front-loaded sentence with two clauses, both of which carry information (what is reported, and the credential-safety boundary). Nothing is redundant or buried.

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-required-parameter read tool this is close, and with no output schema the description does hint at the return shape (state plus timestamp). However, it leaves the meaning of the 'system' selector and the possible session states unstated, so an agent cannot fully predict the response per parameter value.

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 0% for two parameters, and the description compensates for neither. The 'system' enum (shiguang, card_balance, library, timetable, service_portal) is undocumented and the odd const 'session_ref: self' is never explained, leaving the agent to guess what scoping the call performs.

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?

States a specific verb ('Report') and resource ('local session state'), plus the returned datum ('last verified time'). It is clearly distinguishable from domain siblings like upc_timetable_week or upc_card_balance, though the description never explicitly says how it relates to them.

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 when-to-use guidance, no prerequisites, and no mention of alternatives. An agent must infer that this is a pre-flight auth/session check rather than a data-fetching call; nothing in the text states that condition.

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