list_participants

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

With no annotations, the description carries the full burden, but the word "List" plus a read-only shape makes the safety profile reasonably inferable. It does add real behavioral value by disclosing the membership boundary — only participants who have actually sent messages, not every known identity — but says nothing about ordering, pagination, or whether scope is relay-wide or room-scoped.

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 zero filler. The scope qualifier is placed immediately after the verb and resource, so the most useful constraint is read first.

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?

An output schema exists, so return values need not be explained, and the absence of parameters removes most documentation burden. However, the description leaves open whether the listing is relay-wide or room-scoped and whether results are truncated, which matters for a discovery tool in a large relay.

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 the baseline of 4 applies; there is nothing for the description to disambiguate at the argument level. The scope clause in the description is the only parameter-like semantic and it is already covered.

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 and resource ("List all known participants") with a qualifying scope clause ("who have sent messages through the relay"). It is clear on its own, but it never distinguishes itself from adjacent tools such as get_room_state, which plausibly also surfaces participants.

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 guidance on when to call this versus get_room_state, list_rooms, or list_room_tools, and no stated prerequisites or exclusions. Usage is only weakly implied by the word "List".

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