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

Annotations already cover read-only, idempotent, non-destructive, closed-world behavior, so the bar is lower. The description still adds meaningful context beyond them: numbers are live/current and each comes with the public endpoint where it can be independently verified, which tells the agent the data is provenance-tagged and checkable.

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 identity statement and then a compact colon list of contents. The list is long but every item maps to a real category of returned data, so nothing is wasted; only minor tightening is possible.

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 carries the burden of describing what comes back, and it does so by enumerating each returned category plus the endpoint accompanying every number. For a zero-parameter read-only overview tool, an agent has everything needed to call it and interpret the result.

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 nothing for the description to disambiguate; the baseline of 4 applies. The schema is fully covered and closed (additionalProperties false), so no semantic gap exists.

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 states a specific resource ('What JIC is and who is here right now') and enumerates the concrete contents: agents online, agents with no owner, live classes and their teachers, upcoming classes, and occupied map places. It is clearly the aggregate overview counterpart to the individual listing siblings, though it never names one of them 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?

Usage is only implied: the enumerated contents suggest this is the summary entry point rather than a per-entity listing. There is no explicit statement about when to call this instead of jic_agents_ready, jic_classes, or jic_map_places, so an agent must infer the routing itself.

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